Publications by authors named "Lawrence Paszat"

189 Publications

21-Gene Assay and Breast Cancer Mortality in Ductal Carcinoma in Situ.

J Natl Cancer Inst 2020 Dec 28. Epub 2020 Dec 28.

Department of Radiation Oncology, Toronto, ON, Canada.

Background: The inability to identify individuals with ductal carcinoma in situ (DCIS) who are at risk of breast cancer (BC) mortality have hampered efforts to reduce the over-treatment of DCIS. The 21-gene Recurrence Score (RS) predicts distant metastases for individuals with invasive BC, but its prognostic utility in DCIS is unknown.

Methods: We performed a population-based analysis of 1,362 individuals of DCIS aged ≤75 years at diagnosis treated with breast-conserving therapy. We examined the association between a high RS (defined a priori as > 25) and the risk of BC mortality by using a propensity score-adjusted model accounting for the competing risk of death from other causes, testing for interactions. All statistical tests were two-sided.

Results: With 16 years median follow-up, 36 (2.6%) died of BC and 200 (14.7%) died of other causes. The median value of the RS was 15 (range = 0-84); 29.6% of individuals had a high RS. A high RS was associated with an 11-fold increased risk of BC mortality (HR = 11.27 95%CI = 3.00 to 42.33, p<.001 in women ≤50 years of age at diagnosis treated with BCS alone, culminating in a 9.4% (95%CI= 2.3 to 22.5) 20-year risk of BC death. For women with a high RS, treatment with RT was associated with a 71% (HR = 0.29, 95%CI = 0.10 to 0.89. p = .03) relative and a 5% absolute reduction in the 20-year cumulative risk of death from BC.

Conclusion: The 21-gene RS predicts BC mortality in DCIS and combined with age (≤50 years) at diagnosis can identify individuals for whom RT reduces the risk of death from BC.
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http://dx.doi.org/10.1093/jnci/djaa179DOI Listing
December 2020

Morbidity and mortality after major large bowel resection of non-malignant polyp among participants in a population-based screening program.

J Med Screen 2020 Nov 5:969141320967960. Epub 2020 Nov 5.

Institute for Health Care Policy, Management and Evaluation, University of Toronto, Toronto, Canada.

Background And Aims: Colonoscopy following positive fecal occult blood screening may detect non-malignant polyps deemed to require major large bowel resection. We aimed to estimate the major inpatient morbidity and mortality associated with major resection of non-malignant polyps detected at colonoscopy following positive guaiac fecal occult blood screening in Ontario's population-based colorectal screening program.

Methods: We identified those without a diagnosis of colorectal cancer in the Ontario Cancer Registry ≤24 months following the date of colonoscopy prompted by positive fecal occult blood screening between 2008 and 2017, who underwent a major large bowel resection ≤24 months after the colonoscopy, with a diagnosis code for non-malignant polyp, in the absence of a code for any other large bowel diagnosis. We extracted records of major inpatient complications and readmissions ≤30 days following resection. We computed mortality within 90 days following resection.

Results: For those undergoing colonoscopy ≤6 months following positive guaiac fecal occult blood screening, 420/127,872 (0.03%) underwent major large bowel resection for a non-malignant polyp. In 50/420 (11.9%), the resection included one or more rectosigmoid or rectal polyps, with or without a colonic polyp. There were one or more major inpatient complications or readmissions within 30 days in 117/420 (27.9%). Death occurred within 90 days in 6/420 (1.4%).

Conclusions: Serious inpatient complications and readmissions following major large bowel resection for non-malignant colorectal polyps are common, but mortality ≤90 days following resection is low. These outcomes should be considered as unintended adverse consequences of population-based colorectal screening programs.
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http://dx.doi.org/10.1177/0969141320967960DOI Listing
November 2020

Clinical and endoscopist factors associated with post-colonoscopy colorectal cancer in a population-based sample.

Colorectal Dis 2021 Mar 17;23(3):635-645. Epub 2020 Nov 17.

Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Ontario, Canada.

Aim: Factors associated with verified post-colonoscopy colorectal cancers (PCCRC) have not been well defined and survival for these patients is not well described. We aimed to assess the association of patient, tumour and endoscopist characteristics with PCCRC.

Methods: Using population-based data, we identified individuals diagnosed with CRC from 1 January 2000 to 31 December 2005 who underwent a colonoscopy within 3 years prior to diagnosis. Detected cancers were those diagnosed ≤6 months following colonoscopy; PCCRC were diagnosed >6 months to ≤3 years following colonoscopy. Post-colonoscopy and detected cancers were verified through chart review using a hospital-based simple random sampling frame. We used multivariable conditional logistic regression to determine the association of patient, tumour and endoscopist factors with PCCRC and compared overall survival using Cox proportional hazard models.

Results: Using the random sampling frame, we identified 498 patients with PCCRC and 498 with detected CRC; we obtained records and confirmed 367 patients with PCCRC and 412 with detected cancers. In multivariable analysis, patient age (OR 1.01; 95% CI 1.00-1.03) and tumour location (distal vs. proximal OR 0.36; 95% CI 0.25-0.53) were associated with PCCRC; endoscopist quality measures were not significantly associated with PCCRC. We did not find significant differences in overall survival between PCCRC and detected cancers (hazard ratio 1.12; 95% CI 0.92-1.32).

Conclusion: Although endoscopic quality measures are important for CRC prevention, endoscopist factors were not associated with PCCRC. This study highlights the need for further research into the role of tumour biology in PCCRC development.
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http://dx.doi.org/10.1111/codi.15400DOI Listing
March 2021

Morbidity and mortality following major large bowel resection for colorectal cancer detected by a population-based screening program.

J Med Screen 2020 Sep 20:969141320957361. Epub 2020 Sep 20.

Institute for Healthcare Policy, Management and Evaluation, University of Toronto, Toronto, Canada.

Background And Aims: In 2008, Ontario initiated a population-based colorectal screening program using guaiac fecal occult blood testing. This work was undertaken to fill a major gap in knowledge by estimating serious post-operative complications and mortality following major large bowel resection of colorectal cancer detected by a population-based screening program.

Methods: We identified persons with a first positive fecal occult blood result between 2008 and 2016, at the age of 50-74 years, who underwent a colonoscopy within 6 months, and proceeded to major large bowel resection for colon cancer within 6 months or rectosigmoid/rectal cancer within 12 months, and identified an unscreened cohort of resected cases diagnosed during the same years at the age of 50-74 years. We identified serious postoperative complications and readmissions ≤30 days following resection, and postoperative mortality ≤30 days, and between 31 and 90 days among the screen-detected and the unscreened cohorts.

Results: Serious post-operative complications or readmissions within 30 days were observed among 1476/4999 (29.5%) cases in the screen-detected cohort, and among 3060/8848 (34.6%) unscreened cases. Mortality within 30 days was 43/4999 (0.9%) among the screen-detected cohort, and 208/8848 (2.4%) among the unscreened cohort. Among 30 day survivors, mortality between 31 and 90 days was 28/4956 (0.6%) and 111/8640 (1.3%), respectively.

Conclusion: Serious post-operative complications, readmissions, and mortality may be more common following major large bowel resection for colorectal cancer between the ages of 50 and 74 among unscreened compared to screen-detected cases.
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http://dx.doi.org/10.1177/0969141320957361DOI Listing
September 2020

Directly Mailing gFOBT Kits to Previous Responders Being Recalled for Colorectal Cancer Screening Increases Participation.

J Can Assoc Gastroenterol 2020 Oct 18;3(5):197-203. Epub 2019 Oct 18.

Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada.

Background: Colorectal cancer (CRC) screening with guaiac fecal occult blood test (gFOBT) reduces CRC-related death. Average risk individuals should be recalled for screening with gFOBT every 2 years in order to maximize effectiveness. However, adherence with repeated testing is often suboptimal. Our aim was to evaluate whether adding a gFOBT kit to a mailed recall letter improves participation compared with a mailed recall letter alone, among previous responders to a mailed invitation.

Methods: We conducted a cluster randomized controlled trial, with the primary care provider as the unit of randomization. Eligible patients had completed a gFOBT and tested negative in an earlier pilot study and were now due for recall. The intervention group received a mailed CRC screening recall letter from their primary care provider plus a gFOBT kit ( = 431) while the control group received a mailed CRC screening mailed recall letter alone ( = 452). The primary outcome was the uptake of gFOBT or colonoscopy within 6 months.

Results: gFOBT uptake was higher in the intervention group (61.3%, = 264) compared with the control group (50.4%, = 228) with an absolute difference between the two groups of 10.8% (95% confidence interval [CI]: 1.4 to 20.2%, = <0.01). Patients in the intervention group were more likely to complete the gFOBT compared with the control group (odds ratio [OR] = 1.4; 95% CI: 1.1 to 1.9).

Conclusion: Our findings show that adding gFOBT kits to the mailed recall letter increased participation among persons recalled for screening. Nine gFOBT kits would have to be sent by mail in order to screen one additional person.
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http://dx.doi.org/10.1093/jcag/gwz012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7464595PMC
October 2020

Calculation of Stop Ages for Colorectal Cancer Screening Based on Comorbidities and Screening History.

Clin Gastroenterol Hepatol 2021 Mar 23;19(3):547-555. Epub 2020 May 23.

Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands.

Background & Aims: Routine screening for colorectal cancer typically is recommended until age 74 years. Although it has been proposed that a screening stop age could be determined based on sex and comorbidity, less is known about the impact of screening history. We investigated the effects of screening history on the selection of an optimal age to stop screening.

Methods: We used the Microsimulation Screening Analysis-Colon model to estimate the harms and benefits of screening with biennial fecal immunochemical tests by sex, comorbidity status, and screening history. The optimal screening stop age was determined based on the incremental number needed for 1 additional life-year per 1000 screened individuals compared with the threshold provided by stopping screening at 76 years in the average-health population with a perfect screening history (attended all required screening, diagnostic, and follow-up tests) to biennial fecal immunochemical testing from age 50 years.

Results: For persons age 76 years, 157 women and 108 men with a perfect screening history would need to be screened to gain 1 life-year per 1000 screened individuals. Previously unscreened women with no comorbid conditions and no history of screening could undergo an initial screening through 90 years, whereas unscreened men could undergo initial screening through 88 years, before this balance is reached. As screening adherence improved or as comorbidities increased, the optimal age to stop screening decreased to a point that, regardless of sex, individuals with severe comorbidities and a perfect screening history should stop screening at age 66 years or younger.

Conclusions: Based on the harm-benefit balance, the optimal stop age for colorectal cancer screening ranges from 66 years for unhealthy individuals with a perfect screening history to 90 years for healthy individuals without prior screening. These findings can be used to assist patients and clinicians in making decisions about screening participation.
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http://dx.doi.org/10.1016/j.cgh.2020.05.038DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7982961PMC
March 2021

The impact of ductal carcinoma in situ on health services utilization.

Breast Cancer Res Treat 2020 Jul 8;182(1):159-168. Epub 2020 May 8.

University of Toronto, Sunnybrook Research Institute, T2-152 - 2075 Bayview Avenue, Toronto, ON, M4N 3M5, Canada.

Purpose: To determine the intermediate-term impact of diagnosis and treatment of ductal carcinoma in situ of the breast (DCIS) on health services utilization, we compared utilization by cases of DCIS to unaffected controls.

Methods: We identified a population-based cohort of Ontario females diagnosed with DCIS between 2010 and 2015. We matched 5 controls without any history of cancer to each case, on the date of diagnosis of the case (the index date), by age, annual mammography history, socioeconomic status, and comorbidity. We identified billing claims and hospital records, during the interval 13 to 60 months prior to, and subsequent to the index date, and computed rates per 100 person-years during both intervals, to conduct a difference-in-differences analysis. We used negative binomial regression to test if the change in rates in health services differed between cases and controls.

Results: Visits with a breast diagnosis code, and claims for breast surgery and imaging, were significantly increased among cases compared to controls (all p values < 0.0001) after DCIS;however, there was no increase in visits for anxiety or depression (RR 1.13 (95% CI 0.97, 1.32, p = 0.11), visits to psychiatrists (RR 1.07 (95% CI 0.82, 1.40) p = 0.6), or hospital procedures other than breast surgery (RR 1.10 (95% CI 0.88, 1.37) p = 0.4).

Conclusions: DCIS is associated with more visits and procedures related to the breast compared to controls following diagnosis and treatment, but other health services utilization and visits related to anxiety and depression were not increased.
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http://dx.doi.org/10.1007/s10549-020-05664-9DOI Listing
July 2020

Factors Affecting Mean Heart Dose in Patients Receiving Breast Radiotherapy from 2011 to 2018 in a Single Institution.

J Med Imaging Radiat Sci 2020 09 1;51(3):379-393. Epub 2020 May 1.

Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada. Electronic address:

Introduction: Breast cancer radiotherapy (RT) can increase the risk of cardiac disease with increasing dose; as such, reducing excessive dosage to the heart is a concern for clinicians. The purpose of the present study was to assess mean heart dose (MHD) in patients with breast cancer receiving RT, where it was hypothesized that MHD decreased over time.

Methods: Patients planned for adjuvant unilateral whole breast/chest wall RT from 2011 to 2018 were included for a retrospective chart-review at a single-institution, academic center. MHD (Gy) was summarized by laterality, fractionation, and heart-sparing techniques.

Results: A total of 4,687 patients were included. The median MHD for left-sided conventional RT (50 Gy in 25 fractions) was 2.16 Gy across all years, decreasing until 2015 and increasing after. Median MHD for left-sided hypofractionated RT (42.6 Gy in 16 fractions) was 1.47 Gy, also decreasing until 2015 and increasing after. The increase in MHD after 2015 was attributed to a significant increase in the use of wide tangents (including internal mammary chain) after 2015 (P < .0001). Several treatment factors were associated with higher MHD in both right- and left-sided cancers, including locoregional RT, high tangents, wide tangents, bolus, heart shielding, treatment to the chest wall, higher volume of tissue irradiated by tangential fields, higher baseline breast separation values, and smaller heart volume. After adjusting for laterality and fractionation in the multivariate analysis, locoregional RT, wide tangents, heart shielding, boost, treatment to the chest wall, higher volume of tissue irradiated by tangential fields, higher baseline breast separation, and lower heart volume were significantly associated with higher MHD (P < .0001).

Discussion/conclusions: MHD should be considered when determining the most appropriate RT techniques for both right- and left-sided cancers as higher MHD was significantly associated with various treatment techniques and patient factors.
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http://dx.doi.org/10.1016/j.jmir.2020.03.003DOI Listing
September 2020

Cost-effectiveness of Active Identification and Subsequent Colonoscopy Surveillance of Lynch Syndrome Cases.

Clin Gastroenterol Hepatol 2020 Nov 17;18(12):2760-2767.e12. Epub 2019 Oct 17.

Department of Surgery, LiKaShing Knowledge Institute, St Michael's Hospital, Toronto, Canada.

Background & Aims: The province of Ontario, Canada is considering immunohistochemical followed by cascade analyses of all patients who received a diagnosis of colorectal cancer (CRC) at an age younger than 70 years to identify individuals with Lynch syndrome. We evaluated the costs and benefits of testing for Lynch syndrome and determined the optimal surveillance interval for first-degree relatives (FDRs) found to have Lynch syndrome.

Methods: We developed a patient flow diagram to determine costs and yield of immunohistochemical testing for Lynch syndrome in CRC cases and, for those found to have Lynch syndrome, their FDRs, accounting for realistic uptake. Subsequently, we used the MISCAN-colon model to compare costs and benefits of annual, biennial, and triennial surveillance in FDRs identified with Lynch syndrome vs colonoscopy screening every 10 years (usual care for individuals without a diagnosis of Lynch syndrome).

Results: Testing 1000 CRC cases was estimated to identify 20 CRC index cases and 29 FDRs with Lynch syndrome at a cost of $310,274. Despite the high cost of Lynch syndrome tests, offering the FDRs with Lynch syndrome biennial colonoscopy surveillance was cost-effective at $8785 per life-year gained compared with usual care because of a substantial increase in life-years gained (+122%) and cost savings in CRC care. Triennial surveillance was more costly and less effective, and annual surveillance showed limited additional benefit compared with biennial surveillance.

Conclusions: Immunohistochemical testing for Lynch syndrome in persons younger than 70 years who received a diagnosis of CRC and then testing FDRs of those found to have Lynch syndrome provide a good balance between costs and long-term benefits. Colonoscopy surveillance every 2 years is the optimal surveillance interval for patients with Lynch syndrome.
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http://dx.doi.org/10.1016/j.cgh.2019.10.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7162709PMC
November 2020

Economic Analysis of Adjuvant Chemoradiotherapy Compared with Chemotherapy in Resected Pancreas Cancer.

Ann Surg Oncol 2019 Dec 18;26(13):4193-4203. Epub 2019 Sep 18.

Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.

Background: Population-based survival and costs of pancreas adenocarcinoma patients receiving adjuvant chemoradiation and chemotherapy following pancreaticoduodenectomy are poorly understood.

Methods: This retrospective cohort study used linked administrative and pathological datasets to identify all patients diagnosed with pancreas adenocarcinoma and undergoing pancreaticoduodenectomy in Ontario between April 2004 and March 2014, who received postoperative chemoradiation or chemotherapy. Stage and margin status were defined by using pathology reports. Kaplan-Meier and Cox proportional hazards regression survival analyses were used to determine associations between adjuvant treatment approach and survival, while stratifying by margin status. Median overall health system costs were calculated at 1 and 3 years for chemoradiation and chemotherapy, and differences were tested using the Kruskal-Wallis test.

Results: Among 709 patients undergoing pancreaticoduodenectomy for pancreas cancer during the study period, the median survival was 21 months. Median survival was 19 months for chemoradiation and 22 months for chemotherapy. Patients receiving chemoradiation were more likely to have positive margins: 47.7% compared with 19.2% in chemotherapy. After stratifying by margin status and controlling for confounders, adjusted hazard ratio of death were not statistically different between chemotherapy and chemoradiation [margin positive, hazard ratio (HR) = 0.99, 95% confidence interval (CI) = 0.88-1.27; margin negative, HR 0.95, 95% CI 0.91-1.18]. Overall 1-year health system costs were significantly higher for chemoradiation (USD $70,047) than chemotherapy (USD $54,005) (p ≤ 0.001).

Conclusions: Chemotherapy and chemoradiation yielded similar survival, but chemoradiation resulted in higher costs. To create more sustainable healthcare systems, both the efficacy and costs of therapies should be considered.
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http://dx.doi.org/10.1245/s10434-019-07808-8DOI Listing
December 2019

Fractionation in adjuvant radiotherapy for invasive breast cancer and ductal carcinoma in situ in Ontario, Canada from 2009 to 2015.

Breast J 2020 04 12;26(4):602-616. Epub 2019 Sep 12.

Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada.

The use of hypofractionated radiotherapy (HFRT) in patients with breast cancer and ductal carcinoma in situ (DCIS) in Ontario, Canada, from 2009 to 2015 was reported. A retrospective cohort study was conducted using data from the Institute for Clinical Evaluative Sciences (ICES). Patients with a breast cancer or DCIS diagnosis between 2009 and 2015 who received adjuvant breast or chest wall radiation were included. Trends in HFRT use (≤16 fractions) and factors associated with HFRT use in a multivariable logistic regression model with physician-level random effect were reported. The approximate number of hours that could be saved if all patients were to receive HFRT was calculated. A total of 42 072 patients were included. All included characteristics were significantly associated with HFRT use. Hypofractionated radiotherapy use in patients with breast cancer and DCIS increased to around 75% in 2015. In stage I/II patients with mastectomy and chest wall radiation, HFRT use increased to 40% in 2015. Hypofractionated radiotherapy use in patients with regional nodal radiation or reconstruction has increased but remains under 20%. For breast cancer patients with breast-conserving surgery (BCS) and breast radiation, 56 265 visits corresponding to 7200 hours of treatment or 3500 additional HFRT courses could have been saved. In conclusion, HFRT use in Ontario has increased in all patient populations but is nonuniform among physicians and institutions. Use of HFRT in chest wall and regional nodal radiation remains relatively lower than in breast cancer and DCIS patients with BCS.
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http://dx.doi.org/10.1111/tbj.13515DOI Listing
April 2020

The time-varying effect of radiotherapy after breast-conserving surgery for DCIS.

Breast Cancer Res Treat 2019 Nov 31;178(1):221-230. Epub 2019 Jul 31.

Department of Radiation Oncology, Toronto, ON, Canada.

Background: A better understanding underlying radiation (RT) response after breast-conserving surgery (BCS) is needed to mitigate over-treatment of DCIS. The hazard ratio (HR) measures the effect of RT but assumes the effect is constant over time. We examined the hazard function adjusted for adherence to surveillance mammography to examine variations in LR risk and the effect of RT over time.

Methods: Crude hazard estimates for the development of LR in a population cohort of DCIS treated by BCS ± RT were computed. Multivariable extended Cox models and hazard plots were used to examine the association between receipt of RT and risk of each outcome adjusted for baseline covariates and adherence to mammography.

Results: Population cohort includes 3262 women treated by BCS; 1635 received RT. Median follow-up was 13 years. LR developed in 364 women treated by BCS alone and 274 treated with RT. LR risk peaked at 2 years, declined until year 7, and then remained steady. The peak hazard of LR was associated with adverse features of DCIS. Early LR risk was attenuated in patients treated with RT but late annual risks of LR and invasive LR were similar among the two treatment groups. On multivariate analysis, RT was associated with a reduction in early LR risk (HR = 0.52, 95% CI 0.43-0.63, p < 0.0001) but did not reduce the risk of late LR (HR = 0.89, 95% CI: 0.67, 1.19, p = 0.44) (interaction, p = 0.002).

Conclusions: The effect of RT is not uniform over time and greatest in the first 7 years after BCS for DCIS, which can guide future research to understand mechanisms underlying RT response and optimize future management of DCIS.
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http://dx.doi.org/10.1007/s10549-019-05377-8DOI Listing
November 2019

Multiple foci of microinvasion is associated with an increased risk of invasive local recurrence in women with ductal carcinoma in situ treated with breast-conserving surgery.

Breast Cancer Res Treat 2019 Nov 19;178(1):169-176. Epub 2019 Jul 19.

Department of Radiation Oncology, Toronto, ON, Canada.

Purpose: The impact of Ductal Carcinoma in Situ (DCIS) with multiple foci of microinvasion (MI) (≤ 1 mm) on the risks of local recurrence (LR) and invasive LR is unknown, leading to uncertainty if DCIS with multiple foci of MI requires more aggressive treatment. We report a population-based analysis of the impact of multiple foci of MI, confirmed by pathology review, on the 15-year risks of LR and invasive LR treated with breast-conserving surgery (BCS) ± radiotherapy (RT).

Methods: Cohort includes all women diagnosed with DCIS ± MI from 1994 to 2003 treated with BCS ± RT. Cox proportional hazards model was used to evaluate the impact of multiple foci of MI on the risks of LR and invasive LR, adjusting for covariates. The 15-year local and invasive local recurrence-free survival rates were calculated using the Kaplan-Meier method with differences compared by log-rank test.

Results: The cohort includes 2988 women treated by BCS; 2721 had pure DCIS (51% received RT), 267 had DCIS with one or more foci of MI (58% had RT). Median follow-up was 13 years. Median age at diagnosis was 58 years. On multivariable analyses, the presence of multiple foci of MI was associated with an increased risk of invasive LR (HR = 1.59, 95% CI 1.01-2.49, p = 0.04) but not DCIS LR (HR = 0.89, 95% CI 0.46, 1.76, p = 0.7). The 15-year invasive LRFS risks for cases with pure DCIS, with 1 focus or multiple foci of MI were 85.7%, 85.6%, 74.7% following treatment by BCS alone, 87.2%, 89.9%, and 77% for those treated with BCS + RT without boost and 89.2%, 91.3%, and 95% for women treated with BCS + RT and boost.

Conclusions: The presence of multiple foci of MI in DCIS is associated with higher 15-year risks of invasive LR after breast-conserving therapy compared to women with pure DCIS but treatment with whole breast and boost RT can mitigate this risk.
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http://dx.doi.org/10.1007/s10549-019-05364-zDOI Listing
November 2019

Immigration and Adherence to Cervical Cancer Screening: A Provincewide Longitudinal Matched Cohort Study Using Multistate Transitional Models.

J Obstet Gynaecol Can 2019 Jun 27;41(6):813-823. Epub 2018 Oct 27.

Institute for Clinical Evaluative Sciences, Toronto, ON; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON; Department of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, ON.

Objective: Previous studies highlighting inequities in cancer screening between immigrants and non-immigrants have been methodologically limited. This longitudinal matched cohort study used a multistate modelling framework to examine associations between immigration status and cervical cancer screening adherence.

Methods: A 1:1 matched cohort of women aged 25 and older from 1992-2014 who were residing in Ontario was examined. For each woman, the proportion of time spent being non-adherent was determined. Disparities in cervical screening adherence, and specifically the association between immigration status and the rate of becoming adherent, were investigated with a three-state transitional model. The model was adjusted for individual- and physician-level characteristics, which were updated annually and incorporated as time-varying covariates.

Results: The matched cohort consisted of 1 156 720 immigrant and non-immigrant women. The median proportion of time spent non-adherent was 38.9% for immigrants and 24.7% for non-immigrants. The rate of becoming adherent among immigrants was lower than that among non-immigrants, after accounting for individual- and physician-level characteristics (relative rate 0.933; 95% CI 0.928-0.937). Other characteristics such as socioeconomic status, immigrant region of origin, presence of primary physician, and physician's sex were found to be significantly associated with cervical screening adherence.

Conclusion: This study assessed the association between immigration status and adherence to cervical cancer screening. The insights from this work can be used to target groups of women vulnerable to underscreening and to minimize their time spent non-adherent to cancer screening. The methodology serves as a useful framework for examining adherence to other types of cancer screening.
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http://dx.doi.org/10.1016/j.jogc.2018.06.008DOI Listing
June 2019

Patterns of adjuvant care and outcomes of elderly women with stage I breast cancer after breast-conserving surgery: a population-based analysis.

Breast Cancer Res Treat 2019 Aug 10;176(3):657-667. Epub 2019 May 10.

ICES, Toronto, ON, Canada.

Purpose: Randomized trials studying endocrine therapy (ET) with and without radiation therapy (RT) following breast-conserving surgery (BCS) have detected differences in local recurrence (LR) but not survival among elderly women with hormone receptor positive stage I breast cancer (BC). We assembled a population-based cohort of such women to examine the use and outcomes associated with or without the administration of adjuvant radiotherapy (RT) or ET.

Methods: Women aged ≥ 65 years with stage I BC treated with BCS in Ontario between 2010 and 2016, their treatments and outcomes were ascertained using deterministic linkages of administrative databases. Multivariable Cox regression models were used to evaluate risks of ipsilateral LR and of any first in-breast event, categorizing women by their treatment.

Results: 5076 women were treated with BCS followed by RT + ET (n = 1964), RT alone (n = 1325), ET alone (n = 719), or no adjuvant treatment (n = 1068). Median follow-up was 5 years. LR occurred in 0.9% after adjuvant RT + ET, 1.4% after RT alone, 3.1% after ET alone, and 9.4% after BCS alone (p < 0.001). The adjusted risk of LR was increased in those who received no adjuvant therapy (HR = 13.43, CI: 7.89, 22.85), or ET alone (HR = 4.03, CI: 2.14, 7.59). The adjusted risk of any first in-breast event was greatest among those without any adjuvant therapy (HR = 7.61, 95%CI: 5.21, 11.11, p < 0.0001). Absolute and adjusted risks of any first in-breast event were comparable between those with ET alone (HR = 2.09, 95%CI: 1.27, 3.43, p = 0.0038) and those with RT alone (HR = 1.91, 95% CI: 1.25, 2.91, p = 0.0028).

Conclusions: Older women with stage I BC who receive no adjuvant therapy have a significant absolute risk of LR and any first in-breast event, whereas the absolute risk of these events among those with either RT alone or ET alone is only slightly higher than among those treated with both.
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http://dx.doi.org/10.1007/s10549-019-05266-0DOI Listing
August 2019

SV40 seroprevalence in two Latin American countries involved in field trials of candidate oral poliovaccines.

J Infect 2019 06 6;78(6):476-483. Epub 2019 Apr 6.

Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, MS: BCM385, Houston, TX 77030, USA. Electronic address:

Objectives: This study sought to determine SV40 seroprevalence in residents of two Latin American countries, Colombia and Nicaragua, which were sites of prelicensure oral poliovaccine (OPV) trials.

Methods: Archival sera were tested for SV40 neutralizing antibody using a virus-specific plaque-reduction assay. Samples included 517 sera from Colombia and 149 sera from Nicaragua.

Results: Overall SV40 seroprevalence was 22.8% for Colombian subjects and 12.8% for Nicaraguans. Subgroups of Colombian subjects ranged in frequency of SV40 seropositivity from 10.0% to 38.6%. Birth cohorts both older and younger than the age cohort that contained potential OPV vaccinees from both countries had SV40 antibodies. Gender and ethnicity had no significant effects on SV40 seropositivity.

Conclusions: Inhabitants of both Colombia and Nicaragua had detectable SV40 neutralizing antibody, including those of ages presumably not recipients of potentially SV40-contaminated OPV. This observation provides support for the concept that transmission of SV40 human infections can occur. Frequency of SV40 antibody positivity was elevated over that reported for the US where there was limited use of contaminated OPV. This investigation indicates also that study results of SV40 infections in humans will reflect whether subject populations had probable exposures to contaminated poliovaccines and to environmental conditions favoring cycles of viral transmission.
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http://dx.doi.org/10.1016/j.jinf.2019.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6544904PMC
June 2019

Primary care providers' views on a future lung cancer screening program.

Fam Pract 2019 07;36(4):501-505

Dalla Lana School of Public Health, University of Toronto, Toronto, Canada.

Background: The National Lung Screening Trial demonstrated that screening with low-dose computed tomography significantly reduces mortality from lung cancer in high-risk individuals.

Objective: To describe the role preferences and information needs of primary care providers (PCPs) in a future organized lung cancer screening program.

Methods: We purposively sampled PCPs from diverse health regions of Ontario and from different practice models including family health teams and community health centres. We also recruited family physicians with a leadership role in cancer screening. We used focus groups and a nominal group process to identify informational priorities. Two analysts systematically applied a coding scheme to interview transcripts.

Results: Four groups were held with 34 providers and administrative staff [28 (82%) female, 21 (62%) physicians, 7 (20%) other health professionals and 6 (18%) administrative staff]. PCPs and staff were generally positive about a potential lung cancer screening program but had variable views on their involvement. Informational needs included evidence of potential benefits and harms of screening. Most providers preferred that a new program be modelled on positive features of an existing breast cancer screening program. Lung cancer screening was viewed as a new opportunity to counsel patients about smoking cessation.

Conclusions: The development of a future lung cancer screening program should consider the wide variability in the roles that PCPs preferred. An explicit link to existing smoking cessation programs was seen as essential. As providers had significant information needs, learning materials and opportunities should be developed with them.
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http://dx.doi.org/10.1093/fampra/cmy099DOI Listing
July 2019

Reasons For Lack of Follow-up Colonoscopy Among Persons With A Positive Fecal Occult Blood Test Result: A Qualitative Study.

Am J Gastroenterol 2018 12 25;113(12):1872-1880. Epub 2018 Oct 25.

Cancer Care Ontario, Toronto, Canada. Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada. Sunnybrook Research Institute, Toronto, Canada. Department of Medicine, University of Ottawa, Ottawa, Canada. Dalla Lana School of Public Health, University of Toronto, Toronto, Canada. Department of Surgery, St. Michael's Hospital, Toronto, Canada. Institute for Clinical Evaluative Sciences, Toronto, Canada. Department of Medicine, University of Toronto, Toronto, Canada. McMaster University, Hamilton, Canada.

Objectives: Follow-up colonoscopy rates among persons with positive fecal occult blood test results (FOBT + ) remain suboptimal in many jurisdictions. In Ontario, Canada, primary care providers (PCPs) are responsible for arranging follow-up colonoscopies. The objectives were to understand the reasons for a lack of follow-up colonoscopy and any action plans to address follow-up.

Methods: Semi-structured interviews were conducted with 30 FOBT+ persons and 30 PCPs in Ontario. Eligible FOBT+ persons were identified through administrative databases and included those aged 50-74, with a 6-12 month old FOBT+, no follow-up colonoscopy, and no prior colorectal cancer diagnosis or colectomy. Eligible PCPs had ≥1 rostered FOBT+ person without follow-up colonoscopy. Transcripts were analyzed inductively using Nvivo 11 (QSR International Pty Ltd., 2015).

Results: Reasons for lack of follow-up colonoscopy were: person and/or provider believed the FOBT + was a false positive; person was afraid of colonoscopy; person had other health issues; and breakdown in communication of FOBT+ results or colonoscopy appointments. PCPs who initially recommended follow-up colonoscopy did not change the minds of the persons who dismissed the FOBT+ as a false positive and/or who were afraid of the procedure. These FOBT+ persons negotiated an alternative follow-up action plan including repeating the FOBT or not following-up.

Conclusions: PCPs may not adequately counsel FOBT+ persons who believe the FOBT+ is a false positive and/or fear colonoscopy. PCPs may lack fail-safe systems to communicate FOBT+ results and colonoscopy appointments. Using navigators may help address these barriers and increase follow-up rates.
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http://dx.doi.org/10.1038/s41395-018-0381-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6768592PMC
December 2018

The effect of postmastectomy radiotherapy on patient-reported outcomes.

Lancet Oncol 2018 11 15;19(11):1429-1431. Epub 2018 Oct 15.

Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON M4N 3M5, Canada; Department of Radiation Oncology, Toronto, ON, Canada; Institute for Clinical Evaluative Sciences, Toronto, ON, Canada.

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http://dx.doi.org/10.1016/S1470-2045(18)30586-2DOI Listing
November 2018

Risk of Invasive Cervical Cancer Among Immigrants in Ontario, Canada.

J Obstet Gynaecol Can 2019 Jan 10;41(1):21-28. Epub 2018 Oct 10.

Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON. Electronic address:

Background: The risk of invasive cervical cancer (ICC) varies throughout the world. We aimed to compare the risk of this invasive disease among immigrants arriving in Ontario with that of the general female population of Ontario.

Methods: We used an exposure-control matched design. We identified females from the Immigration, Refugees, and Citizenship Canada (IRCC) database with arrival in Ontario, and whose first eligibility for the Ontario Health Insurance Plan according to its Registered Persons Database fell between July 1, 1991, and June 30, 2008, at age 20 years or older, and matched two female controls on year of birth. We identified cases of ICC between the index date and December 31, 2014. Crude rates and relative rates of ICC were calculated. Multivariable extended Cox regression models were then implemented.

Results: The crude rate of ICC was 0.032 per 100 000 person-years for immigrants and 0.037 for controls. Immigrants who were born in certain countries showed a higher risk of ICC; Russia had a relative rate of 1.736 compared with a relative rate of 0.221 among those born in Iran. Among immigrants, the age-adjusted HR was 0.76 (95% CI 0.63-0.92) after 10 years of residency when compared with controls. Immigrants aged 20 to 39 years had a lower risk of ICC compared with controls of equivalent age, and immigrants aged ≥40 years had a higher risk of ICC.

Conclusions: The risk of ICC among immigrants in Ontario varies by age, country of birth, and time since immigration.
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http://dx.doi.org/10.1016/j.jogc.2018.01.031DOI Listing
January 2019

Including the Ductal Carcinoma-In-Situ (DCIS) Score in the Development of a Multivariable Prediction Model for Recurrence After Excision of DCIS.

Clin Breast Cancer 2019 02 29;19(1):35-46. Epub 2018 Jul 29.

University of Toronto, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.

Introduction: Individual prediction of local recurrence (LR) risk after breast-conserving surgery (BCS) for ductal carcinoma-in-situ (DCIS) is needed to identify women at low risk, for whom radiotherapy may be omitted. PATIENTS AND METHODS: Three predictive models of LR-clinicopathologic factors (CPF) alone; CPF + estrogen receptor (ER) + human epidermal growth factor receptor 2 (HER2); and CPF + DCIS score (DS)-were developed among 1102 cases of DCIS in patients with complete covariate and outcome data. Categorizations of discrete variables and transformations of continuous variables were examined in Cox models; 2-way interactions and interactions with time were assessed. Internal validation was performed by bootstrapping. Individual predicted 10-year LR risks were computed from covariate values, estimated regression parameters, and estimated baseline survival function. Accuracy was assessed by c statistics and calibration plots.

Results: The strongest prediction model incorporated CPF + DS. The c statistics for CPF + DS, CPF + ER + HER2, or CPF-alone models were 0.7025, 0.6879, and 0.6825, respectively. The CPF + DS model was better calibrated at predicting low (≤ 10%) individual 10-year LR risks after BCS alone than those incorporating CPF + ER + HER2 or CPF alone, evidenced by c statistics and plots of observed by predicted risks. Among women aged ≥ 50 with no adverse CPF, the CPF + DS model identified the greatest proportion of women (62.3%) with predicted individual 10-year LR ≤ 10% without radiotherapy compared to the CPF + ER + HER2 (50.9%) or CPF alone (46.5%) models.

Conclusion: Individual prediction of LR incorporating DS is more accurate and identifies a higher proportion of women with low predicted risk of LR after BCS alone, for whom radiotherapy may be omitted.
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http://dx.doi.org/10.1016/j.clbc.2018.07.018DOI Listing
February 2019

Validation of 5 key colonoscopy-related data elements from Ontario health administrative databases compared to the clinical record: a cross-sectional study.

CMAJ Open 2018 Jul-Sep;6(3):E330-E338. Epub 2018 Aug 13.

Institute for Clinical Evaluative Sciences (Tinmouth, Sutradhar, Liu, Baxter, Paszat, Rabeneck); Prevention and Cancer Control, Cancer Care Ontario (Tinmouth, Baxter, Rabeneck); Sunnybrook Research Institute (Tinmouth, Paszat, Rabeneck); Li Ka Shing Knowledge Institute (Baxter), St. Michael's Hospital; Dalla Lana School of Public Health (Tinmouth, Sutradhar, Baxter, Paszat, Rabeneck), University of Toronto, Toronto, Ont.

Background: Colonoscopy is used widely, but its quality is highly variable, which may adversely affect patients. Research and quality-improvement initiatives in a variety of jurisdictions have sought to address this issue, often supported by the use of health administrative data. As these data are generally not collected for these purposes, it is critical to measure their validity before use. The aim of this study was to validate health administrative data definitions for 5 key colonoscopy elements through comparison to the clinical record.

Methods: In a cross-sectional study, we randomly sampled 1968 colonoscopy and noncolonoscopy procedures performed at 23 hospitals and 5 nonhospital endoscopy clinics between April 2008 and March 2009 in Ontario. We compared definitions for 5 key colonoscopy elements (colonoscopy case, colonoscopy setting, colonoscopy completeness, anesthesiologist assistance and polypectomy) derived from the health administrative data to the clinical record. We calculated weighted and unweighted sensitivity, specificity and positive predictive value, adjusted for clustering of patients within physicians, for each definition relative to the reference standard.

Results: We abstracted 1845 records; in 1282 cases (69.5%), colonoscopy was intended or performed. The weighted sensitivity and specificity of colonoscopy case, nonhospital colonoscopy setting and anesthesiologist assistance exceeded 95%. The weighted sensitivity for colonoscopy completeness and polypectomy exceeded 95%, but specificity was less than 90%.

Interpretation: Ontario health administrative data definitions for 5 key colonoscopy data elements performed well, with sensitivity and specificity values acceptable for use in research and quality-improvement initiatives. In jurisdictions where health administrative data are similarly used for research or quality improvement, similar studies could be considered.
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http://dx.doi.org/10.9778/cmajo.20180013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6182115PMC
August 2018

Evaluating TNM stage prognostic ability in a population-based cohort of gastric adenocarcinoma patients in a low-incidence country.

Can J Public Health 2018 08 8;109(4):480-488. Epub 2018 Aug 8.

Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada.

Objectives: TNM stage is the preeminent cancer staging system and a fundamental determinant of disease prognosis. Our goal was to evaluate the predictive power of TNM stage for gastric adenocarcinoma (GAC), in a low-incidence country.

Methods: A province-wide chart review of GAC patients diagnosed from April 1, 2005 to March 31, 2008 was conducted in Ontario and linked to routinely collected vital status data with a follow-up on March 31, 2012. TNM staging was classified using the sixth and seventh Union International for Cancer Control/American Joint Committee on Cancer editions. Kaplan-Meier and log-rank tests compared stage-stratified survival estimates. Discrimination was evaluated using Harrell's C statistic.

Results: The cohort included 2366 patients. One- and 5-year survival was 43% and 17%. Using the sixth edition, 9% of patients had stage I disease, 5.4% stage II, 7.3% stage III, and 64% stage IV; 15% were not staged. Using the seventh edition, 9% were stage I, 7.7% stage II, 16% stage III, and 54% stage IV; 14% were not staged. Stage-stratified 5-year survival ranged from 68% to 7% with the sixth edition and from 70% to 4% with the seventh edition. Harrell's C statistic was 0.64 (0.63-0.65) for the broad sixth edition staging categories and 0.68 (0.67-0.69) for the broad seventh edition. Discriminative power was similar for the refined stage categories and across multiple subgroup analyses; it was best in non-metastatic patients.

Conclusion: Existing staging systems for GAC used in North America predict individualized prognosis poorly. The creation of a more complex prediction tool is necessary to provide accurate and precise prognostication information to oncologists, patients, and their families.
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http://dx.doi.org/10.17269/s41997-018-0102-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6964621PMC
August 2018

Reply.

Gastroenterology 2018 06 8;154(8):2279-2280. Epub 2018 May 8.

Sunnybrook Research Institute and Prevention & Cancer Control, Cancer Care Ontario and Department of Medicine, University of Toronto, Ontario, Canada.

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http://dx.doi.org/10.1053/j.gastro.2018.05.018DOI Listing
June 2018

Predictors of non-adherence to colorectal cancer screening among immigrants to Ontario, Canada: a population-based study.

Prev Med 2018 06 13;111:180-189. Epub 2018 Mar 13.

Dalla Lana School of Public Health, Toronto, Ontario, Canada; Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada; Department of Family and Community Medicine, St. Michael's Hospital, Toronto, Ontario, Canada; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada; Centre for Urban Health Solutions, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada; Institute of Health Policy, Management and Evaluation, Toronto, Ontario, Canada.

Though colorectal cancer (CRC) screening rates have increased over time in Ontario, Canada, immigrants continue to have lower rates of screening. This study examines the association between non-adherence to CRC screening and immigration, socio-demographic, healthcare utilization, and primary care physician characteristics among immigrants to Ontario. This is a population-based retrospective cross-sectional study that uses healthcare administrative databases housed at the Institute for Clinical Evaluative Sciences. Our cohort comprised immigrants aged 60 to 74 years who lived in Ontario on March 31, 2015 and who had been eligible for the Ontario Health Insurance Plan for at least 10 years. The outcome was lack of adherence to CRC screening with any modality (fecal occult blood test, flexible sigmoidoscopy, colonoscopy) on March 31, 2015. Our cohort contained 182,949 immigrants. Overall 70,134 (38%) individuals were not adherent to screening. Risk of non-adherence to CRC screening was higher among immigrants who were from low (adjusted relative risk [ARR] 1.35, 95%CI 1.28-1.42) or low-middle (ARR 1.27, 95%CI 1.24-1.30, population-attributable risk [PAR] 9.8%) income countries and refugees (ARR 1.09, 95%CI 1.06-1.11). Compared to those from the United States, Australia, and New Zealand, immigrants from most other world regions, particularly Eastern Europe and Central Asia (ARR 1.28, 95%CI 1.21-1.37), had higher risks of non-adherence. Non-immigration factors such as low healthcare use and lack of primary care enrolment also increased the risk of non-adherence to screening. These findings can be used to inform future efforts to improve uptake of CRC screening among immigrant groups.
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http://dx.doi.org/10.1016/j.ypmed.2018.03.002DOI Listing
June 2018

Higher risk of gastric cancer among immigrants to Ontario: a population-based matched cohort study with over 2 million individuals.

Gastric Cancer 2018 07 28;21(4):588-597. Epub 2017 Dec 28.

Institute for Clinical Evaluative Sciences, G1-06 2075, Bayview Avenue, Toronto, ON, M4N 3M5, Canada.

Background: The risk of gastric carcinoma (GC) varies around the world and between females and males. We aimed to compare the risk of GC among immigrants to Ontario, Canada, to the risk of GC in its general population.

Methods: This was a retrospective population-based matched cohort study from 1991 to 2014. We identified immigrants who were first eligible for the Ontario Health Insurance Plan at age 40 years or older, and matched 5 controls by year of birth and sex. We calculated crude rates and relative rates of GC stratified by sex. We modeled GC hazard using multivariable Cox proportional hazards regression, where a time-varying coefficient was incorporated to examine changes in the association of immigrant status with GC hazard over time.

Results: Among females, 415 GC cases were identified among 209,843 immigrants and 1872 among 1,049,215 controls. Among males, 596 GC cases were identified among 191,792 immigrants and 2998 among 958,960 controls. Comparing immigrants from East Asia and Pacific with the controls, the crude relative rate of GC was 1.54 for females and 1.32 for males. The adjusted hazard ratio (HR) for GC among female immigrants was 1.29 [95% confidence interval (CI) 1.12, 1.48] within 10 years and 1.19 (1.01, 1.40) beyond 10 years; for males, the HR was 1.17 (1.04, 1.31) within 10 years and 1.00 (0.87, 1.15) beyond 10 years.

Conclusion: The risk of GC among immigrants is elevated. Although high-risk immigrant populations in Ontario have been identified, further knowledge is required before a program of GC prevention that is targeted to them can be planned.
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http://dx.doi.org/10.1007/s10120-017-0790-xDOI Listing
July 2018

Piloting electronic screening forms in primary care: findings from a mixed methods study to identify patients eligible for low dose CT lung cancer screening.

BMC Fam Pract 2017 Nov 28;18(1):95. Epub 2017 Nov 28.

Sunnybrook Research Institute, Toronto, ON, Canada.

Background: Recent evidence suggests that screening with low dose computed tomography (LDCT) scans significantly reduces mortality from lung cancer. However, optimal methods to identify potentially eligible patients in primary care are not known. Using brief electronic screening forms administered prior to a primary care visit is a strategy to identify high risk, asymptomatic patients eligible for LDCT screening. The objective of this study was to compare the acceptability and feasibility of using brief electronic versus paper screening forms to identify eligible patients at high risk of developing lung cancer in primary care.

Methods: A mixed method pilot comparative study was conducted in primary care. Practices were allocated to an electronic form (e-form) group or a paper-based form (p-form) group. Allocation was randomly assigned for the first practice then by alternation. Patients in the e-form practices completed forms at home via the web or in the waiting room on a tablet. Patients in p-form practices completed forms in waiting rooms. Interviews were conducted with patients, administrators, and primary care physicians (PCPs) about their experiences.

Results: Six of 30 (20%) eligible practices agreed to participate. Over the 16-week study period, a total of 831 of an expected 1442 patients (58%) aged 55-74 years were enrolled; 573/690 (83%) patients in the e-form group and 258/752 (34%) in the p-form group. Of the 573 participants in the e-form group, 335 (58%) completed forms via the web; 238 (29%) did so via tablet. Twenty-four interviews were conducted with 15 patients, 5 administrative staff and 4 PCPs. Patients were willing to discuss lung cancer screening eligibility with their PCP. Staff members expressed low administrative burden except for an extra step to link appointment information to patient demographics to identify eligible patients. PCPs indicated that forms were reminders to discuss smoking cessation. PCPs in the e-form group reported that patients asked questions about screening.

Conclusion: There was fairly low uptake by primary care practices. For e-forms to be feasible in practice workflow, electronic medical record software needs to link appointment information with patient eligibility requirements. The use of brief pre-consultation electronic screening forms for LDCT eligibility encouraged PCPs to discuss smoking cessation with patients.
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http://dx.doi.org/10.1186/s12875-017-0666-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5704529PMC
November 2017

Repeat Colonoscopy within 6 Months after Initial Outpatient Colonoscopy in Ontario: A Population-Based Cross-Sectional Study.

Can J Gastroenterol Hepatol 2017 7;2017:5917057. Epub 2017 Sep 7.

Prevention and Cancer Control, Cancer Care Ontario, University of Toronto, 620 University Avenue, Toronto, ON, Canada M5G 2L7.

Background: The goal of this study is to examine utilization of early repeat colonoscopy ≤ 6 months after an index procedure.

Methods: We identified persons having repeat colonoscopy ≤ 6 months following outpatient colonoscopy without prior colonoscopy ≤ 5 years or prior diagnosis of colorectal cancer (CRC). We modeled repeat colonoscopy using a generalized estimating equation with an exchangeable correlation structure to account for clustering of patients by endoscopist.

Results: The population included 334,663 persons, 7,892 (2.36%) of whom had an early repeat colonoscopy within 6 months. Overall, endoscopist prior year colonoscopy volume was inversely related to repeat ≤ 6 months. Repeat colonoscopy ≤ 6 months varied by the clinical setting of the index colonoscopy (adjusted OR = 1.41 (95% CI 1.29-1.55)) at nonhospital facilities compared to teaching or community hospitals. Among those who had polypectomy or biopsy, the adjusted OR for early repeat ≤ 6 months was elevated among those whose index colonoscopy was at a nonhospital facility (OR 1.44, 95% CI 1.30-1.60), compared to those at a teaching hospital or community hospital.

Conclusions: Repeat colonoscopy ≤ 6 months after an index procedure is associated with the clinical setting of the index colonoscopy.
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http://dx.doi.org/10.1155/2017/5917057DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610890PMC
August 2018

Effect of Temperature and Time on Fecal Hemoglobin Stability in 5 Fecal Immunochemical Test Methods and One Guaiac Method.

Arch Pathol Lab Med 2018 Jan 2;142(1):75-82. Epub 2017 Oct 2.

From the Medical and Scientific Department, LifeLabs, Toronto, Ontario, Canada (Drs Catomeris and Boss); the Division of General Surgery, St Michael's Hospital, Toronto (Dr Baxter); the Departments of General Surgery (Dr Baxter), Radiation Oncology (Dr Paszat), and Medicine (Drs Rabeneck and Tinmouth), University of Toronto, Toronto; Prevention and Cancer Control, Cancer Care Ontario, Toronto (Drs Rabeneck and Tinmouth); the Division of Laboratory Medicine, Faculty of Medicine, Memorial University of Newfoundland, Health Sciences Centre, St John's, Newfoundland, Canada (Dr Randell); Evaluative Clinical Sciences (Drs Paszat and Tinmouth and Ms Serenity) and Division of Gastroenterology (Dr Tinmouth), Sunnybrook Research Institute, Toronto; the Institute for Clinical Evaluative Sciences, Toronto (Drs Baxter, Paszat, Sutradhar, and Tinmouth); the Institute for Health Policy, Management and Evaluation (Drs Baxter, Paszat, and Tinmouth); and the Department of Biostatistics (Dr Sutradhar), Dalla Lana School of Public Health, University of Toronto, Toronto. Dr Boss is now retired.

Context: - Although promising for colorectal cancer screening, hemoglobin (Hb) stability remains a concern with fecal immunochemical tests. This study implemented a novel, standardized method to compare Hb stability across various fecal immunochemical tests. The method can be used to inform decisions when selecting a kit for use in colorectal cancer screening. In so doing, this work addressed a critical need for standardization in this field.

Objective: - To compare the stability of Hb across 5 different immunochemical kits and one guaiac kit.

Design: - The stability of Hb was analyzed in collection devices inoculated with Hb-spiked feces and (1) stored at various temperatures (frozen, refrigerated, ambient, and elevated) for more than 60 days; (2) after undergoing 3 controlled, freeze-thaw cycles; and (3) after being transported by courier or postal services in uncontrolled temperature conditions from 3 locations in Ontario, Canada, to a central testing center.

Results: - The stability of Hb varied with time and temperature and by kit. Lower Hb recoveries occurred with increasing temperature and increasing time from sample collection to testing. Refrigeration provided the best stability, although results varied across kits (eg, from 4.2 days to >60 days before a prespecified threshold [<70% probability of the test results remaining positive] was reached). Freeze-thaw stability varied across kits and cycles (Hb recoveries: NS Plus [Alfresa Pharma, Chuo-ku, Osaka, Japan], 91.7% to 95.4%; OC Diana [Eiken Chemical, Taito-ku, Tokyo, Japan], 57.6% to 74.9%). Agreement regarding Hb levels before and after transportation varied across kits (from 57% to 100%).

Conclusions: - Important differences in Hb stability were found across the included fecal immunochemical tests. These findings should inform practice-based and population-based colorectal cancer screening.
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http://dx.doi.org/10.5858/arpa.2016-0294-OADOI Listing
January 2018

BETTER HEALTH: Durham -- protocol for a cluster randomized trial of BETTER in community and public health settings.

BMC Public Health 2017 09 29;17(1):754. Epub 2017 Sep 29.

Department of Family and Community Medicine, University of Toronto, 500 University Avenue, Toronto, ON, M5G1V7, Canada.

Background: The Building on Existing Tools to Improve Chronic Disease Prevention and Screening (BETTER) cluster randomized trial in primary care settings demonstrated a 30% improvement in adherence to evidence-based Chronic Disease Prevention and Screening (CDPS) activities. CDPS activities included healthy activities, lifestyle modifications, and screening tests. We present a protocol for the adaptation of BETTER to a public health setting, and testing the adaptation in a cluster randomized trial (BETTER HEALTH: Durham) among low income neighbourhoods in Durham Region, Ontario (Canada).

Methods: The BETTER intervention consists of a personalized prevention visit between a participant and a prevention practitioner, which is focused on the participant's eligible CDPS activities, and uses Brief Action Planning, to empower the participant to set achievable short-term goals.

Better Health: Durham aims to establish that the BETTER intervention can be adapted and proven effective among 40-64 year old residents of low income areas when provided in the community by public health nurses trained as prevention practitioners. Focus groups and key informant interviews among stakeholders and eligible residents of low income areas will inform the adaptation, along with feedback from the trial's Community Advisory Committee. We have created a sampling frame of 16 clusters composed of census dissemination areas in the lowest urban quintile of median household income, and will sample 10 clusters to be randomly allocated to immediate intervention or six month wait list control. Accounting for the clustered design effect, the trial will have 80% power to detect an absolute 30% difference in the primary outcome, a composite score of completed eligible CDPS actions six months after enrollment. The prevention practitioner will attempt to link participants without a primary care provider (PCP) to a local PCP. The implementation of BETTER HEALTH: Durham will be evaluated by focus groups and key informant interviews.

Discussion: The effectiveness of BETTER HEALTH: Durham will be tested for delivery in low income neighbourhoods by a public health department.

Trial Registration: NCT03052959, registered February 10, 2017.
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http://dx.doi.org/10.1186/s12889-017-4797-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5622533PMC
September 2017