Publications by authors named "Elizabeth Alwers"

27 Publications

  • Page 1 of 1

Salicylic Acid and Risk of Colorectal Cancer: A Two-Sample Mendelian Randomization Study.

Nutrients 2021 Nov 21;13(11). Epub 2021 Nov 21.

Department of Medicine and Epidemiology, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA.

Salicylic acid (SA) has observationally been shown to decrease colorectal cancer (CRC) risk. Aspirin (acetylsalicylic acid, that rapidly deacetylates to SA) is an effective primary and secondary chemopreventive agent. Through a Mendelian randomization (MR) approach, we aimed to address whether levels of SA affected CRC risk, stratifying by aspirin use. A two-sample MR analysis was performed using GWAS summary statistics of SA (INTERVAL and EPIC-Norfolk, N = 14,149) and CRC (CCFR, CORECT, GECCO and UK Biobank, 55,168 cases and 65,160 controls). The DACHS study (4410 cases and 3441 controls) was used for replication and stratification of aspirin-use. SNPs proxying SA were selected via three methods: (1) functional SNPs that influence the activity of aspirin-metabolising enzymes; (2) pathway SNPs present in enzymes' coding regions; and (3) genome-wide significant SNPs. We found no association between functional SNPs and SA levels. The pathway and genome-wide SNPs showed no association between SA and CRC risk (OR: 1.03, 95% CI: 0.84-1.27 and OR: 1.08, 95% CI: 0.86-1.34, respectively). Results remained unchanged upon aspirin use stratification. We found little evidence to suggest that an SD increase in genetically predicted SA protects against CRC risk in the general population and upon stratification by aspirin use.
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http://dx.doi.org/10.3390/nu13114164DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8620763PMC
November 2021

Smoking Behavior and Prognosis After Colorectal Cancer Diagnosis: A Pooled Analysis of 11 Studies.

JNCI Cancer Spectr 2021 Oct 31;5(5):pkab077. Epub 2021 Aug 31.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Background: Smoking has been associated with colorectal cancer (CRC) incidence and mortality in previous studies, but current evidence on smoking in association with survival after CRC diagnosis is limited.

Methods: We pooled data from 12 345 patients with stage I-IV CRC from 11 epidemiologic studies in the International Survival Analysis in Colorectal Cancer Consortium. Cox proportional hazards regression models were used to evaluate the associations of prediagnostic smoking behavior with overall, CRC-specific, and non-CRC-specific survival.

Results: Among 12 345 patients with CRC, 4379 (35.5%) died (2515 from CRC) over a median follow-up time of 7.5 years. Smoking was strongly associated with worse survival in stage I-III patients, whereas no association was observed among stage IV patients. Among stage I-III patients, clear dose-response relationships with all survival outcomes were seen for current smokers. For example, current smokers with 40 or more pack-years had statistically significantly worse overall, CRC-specific, and non-CRC-specific survival compared with never smokers (hazard ratio [HR] =1.94, 95% confidence interval [CI] =1.68 to 2.25; HR = 1.41, 95% CI = 1.12 to 1.78; and HR = 2.67, 95% CI = 2.19 to 3.26, respectively). Similar associations with all survival outcomes were observed for former smokers who had quit for less than 10 years, but only a weak association with non-CRC-specific survival was seen among former smokers who had quit for more than 10 years.

Conclusions: This large consortium of CRC patient studies provides compelling evidence that smoking is strongly associated with worse survival of stage I-III CRC patients in a clear dose-response manner. The detrimental effect of smoking was primarily related to noncolorectal cancer events, but current heavy smoking also showed an association with CRC-specific survival.
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http://dx.doi.org/10.1093/jncics/pkab077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8561259PMC
October 2021

Deep learning can predict lymph node status directly from histology in colorectal cancer.

Eur J Cancer 2021 11 11;157:464-473. Epub 2021 Oct 11.

Digital Biomarkers for Oncology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany; German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany. Electronic address:

Background: Lymph node status is a prognostic marker and strongly influences therapeutic decisions in colorectal cancer (CRC).

Objectives: The objective of the study is to investigate whether image features extracted by a deep learning model from routine histological slides and/or clinical data can be used to predict CRC lymph node metastasis (LNM).

Methods: Using histological whole slide images (WSIs) of primary tumours of 2431 patients in the DACHS cohort, we trained a convolutional neural network to predict LNM. In parallel, we used clinical data derived from the same cases in logistic regression analyses. Subsequently, the slide-based artificial intelligence predictor (SBAIP) score was included in the regression. WSIs and data from 582 patients of the TCGA cohort were used as the external test set.

Results: On the internal test set, the SBAIP achieved an area under receiver operating characteristic (AUROC) of 71.0%, the clinical classifier achieved an AUROC of 67.0% and a combination of the two classifiers yielded an improvement to 74.1%. Whereas the clinical classifier's performance remained stable on the TCGA set, performance of the SBAIP dropped to an AUROC of 61.2%. Performance of the clinical classifier depended strongly on the T stage.

Conclusion: Deep learning-based image analysis may help predict LNM of patients with CRC using routine histological slides. Combination with clinical data such as T stage might be useful. Strategies to increase performance of the SBAIP on external images should be investigated.
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http://dx.doi.org/10.1016/j.ejca.2021.08.039DOI Listing
November 2021

Weakly supervised annotation-free cancer detection and prediction of genotype in routine histopathology.

J Pathol 2021 Sep 24. Epub 2021 Sep 24.

Department of Medicine III, University Hospital RWTH Aachen, Aachen, Germany.

Deep learning is a powerful tool in computational pathology: it can be used for tumor detection and for predicting genetic alterations based on histopathology images alone. Conventionally, tumor detection and prediction of genetic alterations are two separate workflows. Newer methods have combined them, but require complex, manually engineered computational pipelines, restricting reproducibility and robustness. To address these issues, we present a new method for simultaneous tumor detection and prediction of genetic alterations: The Slide-Level Assessment Model (SLAM) uses a single off-the-shelf neural network to predict molecular alterations directly from routine pathology slides without any manual annotations, improving upon previous methods by automatically excluding normal and non-informative tissue regions. SLAM requires only standard programming libraries and is conceptually simpler than previous approaches. We have extensively validated SLAM for clinically relevant tasks using two large multicentric cohorts of colorectal cancer patients, Darmkrebs: Chancen der Verhütung durch Screening (DACHS) from Germany and Yorkshire Cancer Research Bowel Cancer Improvement Programme (YCR-BCIP) from the UK. We show that SLAM yields reliable slide-level classification of tumor presence with an area under the receiver operating curve (AUROC) of 0.980 (confidence interval 0.975, 0.984; n = 2,297 tumor and n = 1,281 normal slides). In addition, SLAM can detect microsatellite instability (MSI)/mismatch repair deficiency (dMMR) or microsatellite stability/mismatch repair proficiency with an AUROC of 0.909 (0.888, 0.929; n = 2,039 patients) and BRAF mutational status with an AUROC of 0.821 (0.786, 0.852; n = 2,075 patients). The improvement with respect to previous methods was validated in a large external testing cohort in which MSI/dMMR status was detected with an AUROC of 0.900 (0.864, 0.931; n = 805 patients). In addition, SLAM provides human-interpretable visualization maps, enabling the analysis of multiplexed network predictions by human experts. In summary, SLAM is a new simple and powerful method for computational pathology that could be applied to multiple disease contexts. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.
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http://dx.doi.org/10.1002/path.5800DOI Listing
September 2021

Gastrointestinal cancer classification and prognostication from histology using deep learning: Systematic review.

Eur J Cancer 2021 09 11;155:200-215. Epub 2021 Aug 11.

Digital Biomarkers for Oncology Group, German Cancer Research Center (DKFZ), Heidelberg, Germany. Electronic address:

Background: Gastrointestinal cancers account for approximately 20% of all cancer diagnoses and are responsible for 22.5% of cancer deaths worldwide. Artificial intelligence-based diagnostic support systems, in particular convolutional neural network (CNN)-based image analysis tools, have shown great potential in medical computer vision. In this systematic review, we summarise recent studies reporting CNN-based approaches for digital biomarkers for characterization and prognostication of gastrointestinal cancer pathology.

Methods: Pubmed and Medline were screened for peer-reviewed papers dealing with CNN-based gastrointestinal cancer analyses from histological slides, published between 2015 and 2020.Seven hundred and ninety titles and abstracts were screened, and 58 full-text articles were assessed for eligibility.

Results: Sixteen publications fulfilled our inclusion criteria dealing with tumor or precursor lesion characterization or prognostic and predictive biomarkers: 14 studies on colorectal or rectal cancer, three studies on gastric cancer and none on esophageal cancer. These studies were categorised according to their end-points: polyp characterization, tumor characterization and patient outcome. Regarding the translation into clinical practice, we identified several studies demonstrating generalization of the classifier with external tests and comparisons with pathologists, but none presenting clinical implementation.

Conclusions: Results of recent studies on CNN-based image analysis in gastrointestinal cancer pathology are promising, but studies were conducted in observational and retrospective settings. Large-scale trials are needed to assess performance and predict clinical usefulness. Furthermore, large-scale trials are required for approval of CNN-based prediction models as medical devices.
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http://dx.doi.org/10.1016/j.ejca.2021.07.012DOI Listing
September 2021

Consistent Major Differences in Sex- and Age-Specific Diagnostic Performance among Nine Faecal Immunochemical Tests Used for Colorectal Cancer Screening.

Cancers (Basel) 2021 Jul 16;13(14). Epub 2021 Jul 16.

German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT), Division of Preventive Oncology, 69120 Heidelberg, Germany.

Evidence on diagnostic performance of faecal immunochemical tests (FITs) by sex and age is scarce. We aimed to evaluate FIT performance for detection of advanced colorectal neoplasia (AN) by sex and age across nine different FIT brands in a colonoscopy-controlled setting. The faecal samples were obtained from 2042 participants of colonoscopy screening. All eligible cases with AN ( 216) and 300 randomly selected participants without AN were included. Diagnostic performance for detection of AN was assessed by sex and age (50-64 vs. 65-79 years for each of the nine FITs individually and for all FITs combined. Sensitivity was consistently lower, and specificity was consistently higher for females as compared with males (pooled values at original FIT cutoffs, 25.7% vs. 34.6%, = 0.12 and 96.2% vs. 90.8%, < 0.01, respectively). Positive predictive values (PPVs) were similar between both sexes, but negative predictive values (NPVs) were consistently higher for females (pooled values, 91.8% vs. 86.6%, < 0.01). Sex-specific cutoffs attenuated differences in sensitivities but increased differences in predictive values. According to age, sensitivities and specificities were similar, whereas PPVs were consistently lower and NPVs were consistently higher for the younger participants. A negative FIT is less reliable in ruling out AN among men than among women and among older than among younger participants. Comparisons of measures of diagnostic performance among studies with different sex or age distributions should be interpreted with caution.
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http://dx.doi.org/10.3390/cancers13143574DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8306133PMC
July 2021

DNA Methylation-Based Estimates of Circulating Leukocyte Composition for Predicting Colorectal Cancer Survival: A Prospective Cohort Study.

Cancers (Basel) 2021 Jun 12;13(12). Epub 2021 Jun 12.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany.

Leukocytes are involved in the progression of colorectal cancer (CRC). The proportion of six major leukocyte subtypes can be estimated using epigenome-wide DNA methylation (DNAm) data from stored blood samples. Whether the composition of circulating leukocytes can be used as a prognostic factor is unclear. DNAm-based leukocyte proportions were obtained from a prospective cohort of 2206 CRC patients. Multivariate Cox regression models and survival curves were applied to assess associations between leukocyte composition and survival outcomes. A higher proportion of lymphocytes, including CD4+ T cells, CD8+ T cells, B cells, and NK cells, was associated with better survival, while a higher proportion of neutrophils was associated with poorer survival. CD4+ T cells outperformed other leukocytes in estimating the patients' prognosis. Comparing the highest quantile to the lowest quantile of CD4+ T cells, hazard ratios (95% confidence intervals) of all-cause and CRC-specific mortality were 0.59 (0.48, 0.72) and 0.59 (0.45, 0.77), respectively. Furthermore, the association of CD4+ T cells and prognosis was stronger among patients with early or intermediate CRC or patients with colon cancer. In conclusion, the composition of circulating leukocytes estimated from DNAm, particularly the proportions of CD4+ T cells, could be used as promising independent predictors of CRC survival.
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http://dx.doi.org/10.3390/cancers13122948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8231262PMC
June 2021

Genetically Predicted Circulating C-Reactive Protein Concentration and Colorectal Cancer Survival: A Mendelian Randomization Consortium Study.

Cancer Epidemiol Biomarkers Prev 2021 07 10;30(7):1349-1358. Epub 2021 May 10.

Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.

Background: A positive association between circulating C-reactive protein (CRP) and colorectal cancer survival was reported in observational studies, which are susceptible to unmeasured confounding and reverse causality. We used a Mendelian randomization approach to evaluate the association between genetically predicted CRP concentrations and colorectal cancer-specific survival.

Methods: We used individual-level data for 16,918 eligible colorectal cancer cases of European ancestry from 15 studies within the International Survival Analysis of Colorectal Cancer Consortium. We calculated a genetic-risk score based on 52 CRP-associated genetic variants identified from genome-wide association studies. Because of the non-collapsibility of hazard ratios from Cox proportional hazards models, we used the additive hazards model to calculate hazard differences (HD) and 95% confidence intervals (CI) for the association between genetically predicted CRP concentrations and colorectal cancer-specific survival, overall and by stage at diagnosis and tumor location. Analyses were adjusted for age at diagnosis, sex, body mass index, genotyping platform, study, and principal components.

Results: Of the 5,395 (32%) deaths accrued over up to 10 years of follow-up, 3,808 (23%) were due to colorectal cancer. Genetically predicted CRP concentration was not associated with colorectal cancer-specific survival (HD, -1.15; 95% CI, -2.76 to 0.47 per 100,000 person-years; = 0.16). Similarly, no associations were observed in subgroup analyses by stage at diagnosis or tumor location.

Conclusions: Despite adequate power to detect moderate associations, our results did not support a causal effect of circulating CRP concentrations on colorectal cancer-specific survival.

Impact: Future research evaluating genetically determined levels of other circulating inflammatory biomarkers (i.e., IL6) with colorectal cancer survival outcomes is needed.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-1848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8254760PMC
July 2021

Uptake Rates of Novel Therapies and Survival Among Privately Insured Versus Publicly Insured Patients With Colorectal Cancer in Germany.

J Natl Compr Canc Netw 2021 04 12;19(4):411-420. Epub 2021 Feb 12.

1Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg.

Background: In the era of personalized medicine, cancer care is subject to major changes and innovations. It is unclear, however, to what extent implementation of such innovations and their impact on patient outcomes differ by health insurance type. This study compared provision of treatment and survival outcomes among patients with colorectal cancer (CRC) who had statutory health insurance (SHI) versus private health insurance (PHI) in Germany.

Methods: We analyzed patterns of CRC treatment (surgery, chemotherapy/radiotherapy, and targeted therapy) and survival in a large cohort of patients who were diagnosed with CRC in 2003 through 2014 and were observed for an average of 6 years. Associations of type of health insurance with treatment administration and with overall, CRC-specific, and recurrence-free survival were investigated using multivariable logistic and Cox proportional hazards models, respectively.

Results: Of 3,977 patients with CRC, 427 (11%) had PHI. Although type of health insurance was not associated with treatment administration in patients with stage I-III disease, those with stage IV disease with PHI more often received targeted therapy (65% vs 40%; odds ratio, 2.43; 95% CI, 1.20-4.91), with differences decreasing over time because of catch-up of uptake rates in patients with SHI. Median overall survival was longer in patients with PHI than in those with SHI (137.0 vs 114.9 months; P=.010), but survival advantages were explained to a large extent by differences in sociodemographic factors. In patients with stage IV disease, survival advantages of PHI were nonsignificant and were restricted to the early years after diagnosis.

Conclusions: We observed major differences in uptake of targeted therapy between patients with PHI and those with SHI but no differences in patient survival after adjusting for relevant sociodemographic, clinical, and tumor characteristics. Further studies are needed on factors associated with the uptake of therapeutic innovations and their impact on patient survival by health insurance type.
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http://dx.doi.org/10.6004/jnccn.2020.7636DOI Listing
April 2021

Response to neoadjuvant treatment among rectal cancer patients in a population-based cohort.

Int J Colorectal Dis 2021 Jan 19;36(1):177-185. Epub 2020 Sep 19.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.

Background: In rectal cancer, prediction of tumor response and pathological complete response (pCR) to neoadjuvant treatment could contribute to refine selection of patients who might benefit from a delayed- or no-surgery approach. The aim of this study was to explore the association of clinical and molecular characteristics of rectal cancer with response to neoadjuvant treatment and to compare patient survival according to level of response.

Methods: Resected rectal cancer patients were selected from a population-based cohort study. Molecular tumor markers were determined from the surgical specimen. Tumor response and pCR were defined as downstaging in T or N stage and absence of tumor cells upon pathological examination, respectively. The associations of patient and tumor characteristics with tumor response and pCR were explored, and patient survival was determined by degree of response to neoadjuvant treatment.

Results: Among 1536 patients with rectal cancer, 602 (39%) received neoadjuvant treatment. Fifty-five (9%) patients presented pCR, and 239 (49%) and 250 (53%) patients showed downstaging of the T and N stages, respectively. No statistically significant associations were observed between patient or tumor characteristics and tumor response or pCR. Patients who presented any type of response to neoadjuvant treatment had significantly better cancer-specific and overall survival compared with non-responders.

Conclusion: In this study, patient characteristics were not associated with response to neoadjuvant treatment, and molecular characteristics determined after surgical resection of the tumor were not predictive of pCR or tumor downstaging. Future studies should include molecular biomarkers from biopsy samples before neoadjuvant treatment.
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http://dx.doi.org/10.1007/s00384-020-03744-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782441PMC
January 2021

Age-dependent performance of BRAF mutation testing in Lynch syndrome diagnostics.

Int J Cancer 2020 11 14;147(10):2801-2810. Epub 2020 Sep 14.

Department of Applied Tumor Biology, University Hospital Heidelberg, Cooperation Unit Applied Tumor Biology, German Cancer research Center (DKFZ), and Molecular Medicine Partnership Unit (MMPU), University Hospital Heidelberg, Heidelberg, Germany.

BRAF V600E mutations have been reported as a marker of sporadic microsatellite instability (MSI) colorectal cancer (CRC). Current international diagnostic guidelines recommend BRAF mutation testing in MSI CRC patients to predict low risk of Lynch syndrome (LS). We evaluated the age-specific performance of BRAF testing in LS diagnostics. We systematically compared the prevalence of BRAF mutations in LS-associated CRCs and unselected MSI CRCs in different age groups as available from published studies, databases and population-based patient cohorts. Sensitivity/specificity analysis of BRAF testing for exclusion of LS and cost calculations were performed. Among 969 MSI CRCs from LS carriers in the literature and German HNPCC Consortium, 15 (1.6%) harbored BRAF mutations. Six of seven LS patients with BRAF-mutant CRC and reported age were <50 years. Among 339 of 756 (44.8%) of BRAF mutations detected in unselected MSI CRC, only 2 of 339 (0.6%) BRAF mutations were detected in patients <50 years. The inclusion of BRAF testing led to high risk of missing LS patients and increased costs at age <50 years. BRAF testing in patients <50 years carries a high risk of missing a hereditary cancer predisposition and is cost-inefficient. We suggest direct referral of MSI CRC patients <50 years to genetic counseling without BRAF testing.
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http://dx.doi.org/10.1002/ijc.33273DOI Listing
November 2020

Colonoscopy and Reduction of Colorectal Cancer Risk by Molecular Tumor Subtypes: A Population-Based Case-Control Study.

Am J Gastroenterol 2020 12;115(12):2007-2016

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Introduction: In previous studies, the protective effect of colonoscopy was generally stronger for distal colorectal cancer than for proximal colorectal cancer (CRC). This study aimed to investigate whether reduction of CRC risk through colonoscopy varies according to major tumor markers and pathways of CRC.

Methods: This is a population-based case-control study from Germany, including 2,132 patients with a first diagnosis of CRC and information on major molecular tumor markers and 2,486 control participants without CRC. Detailed participant characteristics were collected by standardized questionnaires. Information on previous colonoscopy was derived from medical records. Polytomous logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association between previous colonoscopy and subtypes of CRC.

Results: Overall, we observed strong risk reduction of CRC after colonoscopy that was weaker for microsatellite instable (MSI) than for non-MSI CRC (OR 0.70, 95% CI 0.50-0.97 vs OR 0.28, 95% CI 0.24-0.33), for CpG island methylator phenotype high CRC than for CpG island methylator phenotype low/negative CRC (OR 0.45, 95% CI 0.34-0.59 vs OR 0.29, 95% CI 0.25-0.34), for BRAF-mutated than for BRAF nonmutated CRC (OR 0.62, 95% CI 0.42-0.91 vs OR 0.30, 95% CI 0.25-0.35), for KRAS nonmutated than for KRAS-mutated CRC (OR 0.34, 95% CI 0.29-0.40 vs OR 0.26, 95% CI 0.20-0.32), and for CRC classified into the sessile serrated pathway than for CRC of the traditional pathway (OR 0.57, 95% CI 0.36-0.91 vs OR 0.30, 95% CI 0.25-0.37). After colonoscopy with the detection of adenomas or hyperplastic polyps, no risk reduction was found for sessile serrated pathway CRC, MSI, and BRAF-mutated subtypes.

Discussion: Our study extends the molecular understanding of existing differences in risk reduction of proximal and distal CRCs reported by previous studies and may imply important information for improving strategies for timely detection of relevant precursors.
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http://dx.doi.org/10.14309/ajg.0000000000000819DOI Listing
December 2020

Landscape of somatic single nucleotide variants and indels in colorectal cancer and impact on survival.

Nat Commun 2020 07 20;11(1):3644. Epub 2020 Jul 20.

Department of Preventive Medicine, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1441 Eastlake Avenue, Los Angeles, CA, 90089, USA.

Colorectal cancer (CRC) is a biologically heterogeneous disease. To characterize its mutational profile, we conduct targeted sequencing of 205 genes for 2,105 CRC cases with survival data. Our data shows several findings in addition to enhancing the existing knowledge of CRC. We identify PRKCI, SPZ1, MUTYH, MAP2K4, FETUB, and TGFBR2 as additional genes significantly mutated in CRC. We find that among hypermutated tumors, an increased mutation burden is associated with improved CRC-specific survival (HR = 0.42, 95% CI: 0.21-0.82). Mutations in TP53 are associated with poorer CRC-specific survival, which is most pronounced in cases carrying TP53 mutations with predicted 0% transcriptional activity (HR = 1.53, 95% CI: 1.21-1.94). Furthermore, we observe differences in mutational frequency of several genes and pathways by tumor location, stage, and sex. Overall, this large study provides deep insights into somatic mutations in CRC, and their potential relationships with survival and tumor features.
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http://dx.doi.org/10.1038/s41467-020-17386-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371703PMC
July 2020

Clinical-Grade Detection of Microsatellite Instability in Colorectal Tumors by Deep Learning.

Gastroenterology 2020 10 17;159(4):1406-1416.e11. Epub 2020 Jun 17.

Department of Medicine III, University Hospital RWTH Aachen, Aachen, Germany; Pathology and Data Analytics, Leeds Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom; German Cancer Consortium, German Cancer Research Center, Heidelberg, Germany; Medical Oncology, National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany. Electronic address:

Background & Aims: Microsatellite instability (MSI) and mismatch-repair deficiency (dMMR) in colorectal tumors are used to select treatment for patients. Deep learning can detect MSI and dMMR in tumor samples on routine histology slides faster and less expensively than molecular assays. However, clinical application of this technology requires high performance and multisite validation, which have not yet been performed.

Methods: We collected H&E-stained slides and findings from molecular analyses for MSI and dMMR from 8836 colorectal tumors (of all stages) included in the MSIDETECT consortium study, from Germany, the Netherlands, the United Kingdom, and the United States. Specimens with dMMR were identified by immunohistochemistry analyses of tissue microarrays for loss of MLH1, MSH2, MSH6, and/or PMS2. Specimens with MSI were identified by genetic analyses. We trained a deep-learning detector to identify samples with MSI from these slides; performance was assessed by cross-validation (N = 6406 specimens) and validated in an external cohort (n = 771 specimens). Prespecified endpoints were area under the receiver operating characteristic (AUROC) curve and area under the precision-recall curve (AUPRC).

Results: The deep-learning detector identified specimens with dMMR or MSI with a mean AUROC curve of 0.92 (lower bound, 0.91; upper bound, 0.93) and an AUPRC of 0.63 (range, 0.59-0.65), or 67% specificity and 95% sensitivity, in the cross-validation development cohort. In the validation cohort, the classifier identified samples with dMMR with an AUROC of 0.95 (range, 0.92-0.96) without image preprocessing and an AUROC of 0.96 (range, 0.93-0.98) after color normalization.

Conclusions: We developed a deep-learning system that detects colorectal cancer specimens with dMMR or MSI using H&E-stained slides; it detected tissues with dMMR with an AUROC of 0.96 in a large, international validation cohort. This system might be used for high-throughput, low-cost evaluation of colorectal tissue specimens.
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http://dx.doi.org/10.1053/j.gastro.2020.06.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7578071PMC
October 2020

Smoking, alcohol consumption and colorectal cancer risk by molecular pathological subtypes and pathways.

Br J Cancer 2020 05 30;122(11):1604-1610. Epub 2020 Mar 30.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Background: Smoking and alcohol increase risk for colorectal malignancies. However, colorectal cancer (CRC) is a heterogenic disease and associations with the molecular pathological pathways are unclear.

Methods: This population-based case-control study includes 2444 cases with first-diagnosis CRC and 2475 controls. Tumour tissue was analysed for MSI (microsatellite instability), CIMP (CpG island methylator phenotype), BRAF (B-Raf proto-oncogene serine/threonine kinase gene) and KRAS (Kirsten rat sarcoma viral oncogene homologue gene) mutations. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated for associations between alcohol and smoking and CRC molecular subtypes and pathways.

Results: Current smoking showed higher ORs for MSI-high (OR = 2.79, 95% CI: 1.86-4.18) compared to MSS (OR = 1.41, 1.14-1.75, p-heterogeneity (p-het) = 0.001), BRAF-mutated (mut) (OR = 2.40, 1.41-4.07) compared to BRAF-wild type (wt) (OR = 1.52, 1.24-1.88, p-het = 0.074), KRAS-wt (OR = 1.70, 1.36-2.13) compared to KRAS-mut (OR = 1.26, 0.95-1.68, p-het = 0.039) and CIMP-high (OR = 2.01, 1.40-2.88) compared to CIMP-low/negative CRC (OR = 1.50, 1.22-1.85, p-het=0.101). Current smoking seemed more strongly associated with sessile serrated pathway (CIMP-high + BRAF-mut; OR = 2.39, 1.27-4.52) than with traditional pathway CRC (MSS + CIMP-low/negative + BRAF-wt; OR = 1.50, 1.16-1.94) and no association was observed with alternate pathway CRC (MSS + CIMP-low/negative + KRAS-wt; OR = 1.08, 0.77-1.43). No heterogeneity was observed in alcohol consumption association by molecular subtypes.

Conclusions: In this large case-control study, smoking was more strongly associated with MSI-high and KRAS-wt CRC and with cases showing features of the sessile serrated pathway. Association patterns were less clear for alcohol consumption.
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http://dx.doi.org/10.1038/s41416-020-0803-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7250912PMC
May 2020

[Design and quality control of the oral health status examination in the German National Cohort (GNC)].

Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2020 Apr;63(4):426-438

Institut für Epidemiologie und Sozialmedizin, Westfälische Wilhelms-Universität Münster, Münster, Deutschland.

Background: Caries and periodontitis are highly prevalent worldwide. Because detailed data on these oral diseases were collected within the framework of the German National Cohort (GNC), associations between oral and systemic diseases and conditions can be investigated.

Objectives: The study protocol for the oral examination was designed to ensure a comprehensive collection of dental findings by trained non-dental staff within a limited examination time. At the mid-term of the GNC baseline examination, a first quality evaluation was performed to check the plausibility of results and to propose measures to improve the data quality.

Materials And Methods: A dental interview, saliva sampling and oral diagnostics were conducted. As part of the level‑1 examination, the number of teeth and prostheses were recorded. As part of the level‑2 examination, detailed periodontal, cariological and functional aspects were examined. All examinations were conducted by trained non-dental personnel. Parameters were checked for plausibility and variable distributions were descriptively analysed.

Results: Analyses included data of 57,967 interview participants, 56,913 level‑1 participants and 6295 level‑2 participants. Percentages of missing values for individual clinical parameters assessed in level 1 and level 2 ranged between 0.02 and 3.9%. Results showed a plausible distribution of the data; rarely, implausible values were observed, e.g. for measurements of horizontal and vertical overbite (overjet and overbite). Intra-class correlation coefficients indicated differences in individual parameters between regional clusters, study centres and across different examiners.

Conclusions: The results confirm the feasibility of the study protocol by non-dental personnel and its successful integration into the GNC's overall assessment program. However, rigorous dental support of the study centres is required for quality management.
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http://dx.doi.org/10.1007/s00103-020-03107-wDOI Listing
April 2020

Association Between Molecular Subtypes of Colorectal Tumors and Patient Survival, Based on Pooled Analysis of 7 International Studies.

Gastroenterology 2020 06 20;158(8):2158-2168.e4. Epub 2020 Feb 20.

Epidemiology Department, University of Washington, Seattle, Washington; Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington.

Background And Aims: The heterogeneity among colorectal tumors is probably due to differences in developmental pathways and might associate with patient survival times. We studied the relationship among markers of different subtypes of colorectal tumors and patient survival.

Methods: We pooled data from 7 observational studies, comprising 5010 patients with colorectal cancer. All the studies collected information on microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and mutations in KRAS and BRAF in tumors. Tumors with complete marker data were classified as type 1 (MSI-high, CIMP-positive, with pathogenic mutations in BRAF but not KRAS), type 2 (not MSI-high, CIMP-positive, with pathogenic mutations in BRAF but not KRAS), type 3 (not MSI-high or CIMP, with pathogenic mutations in KRAS but not BRAF), type 4 (not MSI-high or CIMP, no pathogenic mutations in BRAF or KRAS), or type 5 (MSI-high, no CIMP, no pathogenic mutations in BRAF or KRAS). We used Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CIs) for associations of these subtypes and tumor markers with disease-specific survival (DSS) and overall survival times, adjusting for age, sex, stage at diagnosis, and study population.

Results: Patients with type 2 colorectal tumors had significantly shorter time of DSS than patients with type 4 tumors (HR 1.66; 95% CI 1.33-2.07), regardless of sex, age, or stage at diagnosis. Patients without MSI-high tumors had significantly shorter time of DSS compared with patients with MSI-high tumors (HR 0.42; 95% CI 0.27-0.64), regardless of other tumor markers or stage, or patient sex or age.

Conclusions: In a pooled analysis of data from 7 observational studies of patients with colorectal cancer, we found that tumor subtypes, defined by combinations of 4 common tumor markers, were associated with differences in survival time. Colorectal tumor subtypes might therefore be used in determining patients' prognoses.
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http://dx.doi.org/10.1053/j.gastro.2020.02.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7282955PMC
June 2020

Postmenopausal hormone replacement therapy and colorectal cancer risk by molecular subtypes and pathways.

Int J Cancer 2020 08 30;147(4):1018-1026. Epub 2020 Jan 30.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Postmenopausal hormone replacement therapy (HRT) was found to be associated with lower risk of colorectal cancer (CRC). However, little is known regarding associations with molecular subtypes of CRC. The current study includes female participants of a large German population-based case-control study (922 CRC cases and 1,183 controls). Tumor tissue samples were analyzed for microsatellite instability (MSI), CpG island methylator phenotype (CIMP), BRAF and KRAS mutation status. Multivariable logistic regression models were used to assess the association of HRT use with molecular subtypes and pathways. Postmenopausal HRT use was overall associated with reduced risk of CRC (adjusted odds ratio (aOR) 0.62, 95% confidence interval (CI) 0.50-0.76) and no major differences were observed for molecular subtypes or for tumor marker combinations representing molecular pathways. When stratified by median age (≤/>71 years) potentially stronger risk reductions were observed in the older group for subtypes showing MSI (OR = 0.36, 95% CI 0.17-0.76), BRAF mutation (OR = 0.40, 95% CI 0.30-0.83) and CIMP-high (OR = 0.40, 95% CI 0.21-0.73) and for CRC suggestive of the sessile serrated pathway (OR = 0.45, 95% CI 0.20-1.01). In conclusion, postmenopausal use of HRT was similarly associated with risk reduction of major molecular tumor subtypes and pathways of CRC. Potentially stronger risk reductions with CRC subtypes diagnosed at higher ages require confirmation and clarification from other studies. The current study extends the limited understanding of the mechanisms of HRT in CRC prevention.
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http://dx.doi.org/10.1002/ijc.32868DOI Listing
August 2020

Association of BMI and major molecular pathological markers of colorectal cancer in men and women.

Am J Clin Nutr 2020 03;111(3):562-569

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Heidelberg, Germany.

Background: Observational studies have consistently shown that a high BMI is associated with increased risk of colorectal cancer (CRC). However, the underlying mechanisms linking obesity to CRC remain unclear.

Objectives: To investigate the associations of BMI and CRC by major molecular pathological subtypes of CRC.

Methods: This analysis included 2407 cases and 2454 controls from a large German population-based case-control study. Information on recent weight and height as well as other demographic and lifestyle data were obtained by standardized interviews. Multinomial logistic regression was used to estimate ORs and 95% CIs for the associations between BMI and risk of CRC by major molecular pathological features: microsatellite instability (MSI), CpG island methylator phenotype (CIMP), B-Raf proto-oncogene serine/threonine kinase (BRAF) mutation, and Kirsten rat sarcoma viral oncogene homolog gene (KRAS) mutation.

Results: Among women, a higher BMI was differentially and more strongly associated with risk of MSI CRC (OR per 5 kg/m2: 1.69; 95% CI: 1.34, 2.12; Pheterogeneity ≤ 0.001), CIMP-high CRC (OR per 5 kg/m2: 1.57; 95% CI: 1.30, 1.89; Pheterogeneity ≤ 0.001), BRAF-mutated CRC (OR per 5 kg/m2: 1.56; 95% CI: 1.22, 1.99; Pheterogeneity = 0.04), and KRAS-wildtype CRC (OR per 5 kg/m2: 1.35; 95% CI: 1.17, 1.54; Pheterogeneity = 0.01), compared with the risk of CRC in subjects with the molecular feature counterpart. In men, no meaningful differences in CRC risk were observed for the investigated molecular feature pairs. For the association of BMI with MSI CRC, we observed effect modification by sex (Pinteraction = 0.04). Also, in women, the risk of CRC with the serrated pathway features was more strongly increased with higher BMI than risk of CRC with the traditional pathway features (OR per 5 kg/m2: 1.73; 95% CI: 1.28, 2.34; Pheterogeneity = 0.01).

Conclusions: In women, the relation between BMI and MSI-high CRC seems to be stronger than that between BMI and microsatellite-stable CRC. However, a validation in an independent cohort is needed. This observational study was registered at the German Clinical Trials Register (http://www.drks.de; study ID: DRKS00011793), an approved primary register in the WHO network.
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http://dx.doi.org/10.1093/ajcn/nqz315DOI Listing
March 2020

Microsatellite instability and survival after adjuvant chemotherapy among stage II and III colon cancer patients: results from a population-based study.

Mol Oncol 2020 02 7;14(2):363-372. Epub 2020 Jan 7.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Previous studies have reported conflicting results regarding the benefit of administering 5-FU-based chemotherapy to colon cancer (CC) patients with microsatellite-instable (MSI-high) tumors, and results from stage-specific analyses are scarce. Patients with stage II or III CC were recruited as part of a population-based study between 2003 and 2015. The Cox regression models including propensity score weighting were used to calculate hazard ratios and confidence intervals for the association between chemotherapy and cancer-specific (CSS), relapse-free (RFS), and overall survival (OS) by stage of disease and MSI status of the tumor. Median follow-up was 6.2 years. A total of 1010 CC patients were included in the analysis (54% stage II, 46% stage III, 20% MSI-high). Adjuvant chemotherapy was administered to 48 (8.7%) stage II and 366 (79%) stage III patients. Overall, patients who received adjuvant chemotherapy had better CSS [HR = 0.65 (0.49-0.86)] than those who received surgery alone. Among stage II patients, only 64 (12%) cancer-related deaths occurred, none of which in MSI-high patients who received chemotherapy. Patients with MSI-high tumors who received adjuvant treatment showed better CSS and a tendency toward better RFS compared to MSI-high patients who did not receive chemotherapy [HR  = 0.36 (0.15-0.82), HR  = 0.49 (0.22-1.06)]. Patients with microsatellite-stable (MSS) tumors receiving adjuvant chemotherapy also had significantly better survival [HR  = 0.65 (0.48-0.87) and HR  = 0.68 (0.52-0.88)]. In this population-based study including stage II and III CC patients, we observed a survival benefit of adjuvant chemotherapy for both MSS and MSI-high tumors. Adjuvant chemotherapy seemed to be beneficial among high-risk stage II patients with MSI-high tumors.
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http://dx.doi.org/10.1002/1878-0261.12611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6998383PMC
February 2020

Identification of prognostic DNA methylation biomarkers in patients with gastrointestinal adenocarcinomas: A systematic review of epigenome-wide studies.

Cancer Treat Rev 2020 Jan 23;82:101933. Epub 2019 Nov 23.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, Heidelberg, Germany. Electronic address:

This systematic review aims to summarize epigenome-wide studies on aberrant DNA methylation and its association with survival in patients with gastrointestinal adenocarcinoma. The 15 studies identified showed a large variety of methodological approaches for the identification of prognostic epigenetic markers from genome-wide methylation analyses. None of the findings were reported by more than one study in this systematic review. Further validation studies, a better reporting of methods and results are needed, as well as a clearer definition of investigated outcomes. At present, no conclusions can be drawn on the clinical relevance of the reported epigenetic markers.
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http://dx.doi.org/10.1016/j.ctrv.2019.101933DOI Listing
January 2020

External validation of molecular subtype classifications of colorectal cancer based on microsatellite instability, CIMP, BRAF and KRAS.

BMC Cancer 2019 Jul 11;19(1):681. Epub 2019 Jul 11.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120, Heidelberg, Germany.

Background: Competing molecular classification systems have been proposed to complement the TNM staging system for a better prediction of survival in colorectal cancer (CRC). However, validation studies are so far lacking. The aim of this study was to validate and extend previously published molecular classifications of CRC in a large independent cohort of CRC patients.

Methods: CRC patients were recruited into a population-based cohort study (DACHS). Molecular subtypes were categorized based on three previously published classifications. Cox-proportional hazard models, based on the same set of patients and using the same confounders as reported by the original studies, were used to determine overall, cancer-specific, or relapse-free survival for each subtype. Hazard ratios and confidence intervals, as well as Kaplan-Meier plots were compared to those reported by the original studies.

Results: We observed similar patterns of worse survival for the microsatellite stable (MSS)/BRAF-mutated and MSS/KRAS-mutated subtypes in our validation analyses, which were included in two of the validated classifications. Of the two MSI subtypes, one defined by additional presence of CIMP-high and BRAF-mutation and the other by tumors negative for CIMP, BRAF and KRAS-mutations, we could not confirm associations with better prognosis as suggested by one of the classifications. For two of the published classifications, we were able to provide results for additional subgroups not included in the original studies (men, other disease stages, other locations).

Conclusions: External validation of three previously proposed classifications confirmed findings of worse survival for CRC patients with MSS subtypes and BRAF or KRAS mutations. Regarding MSI subtypes, other patient characteristics such as stage of the tumor, may influence the potential survival benefit. Further integration of methylation, genetic, and immunological information is needed to develop and validate a comprehensive classification that will have relevance for use in clinical practice.
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http://dx.doi.org/10.1186/s12885-019-5842-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6624952PMC
July 2019

Genome-wide DNA methylation differences according to oestrogen receptor beta status in colorectal cancer.

Epigenetics 2019 05 30;14(5):477-493. Epub 2019 Mar 30.

a Division of Cancer Epidemiology , German Cancer Research Center , Heidelberg , Germany.

Involvement of sex hormones in colorectal cancer (CRC) development has been linked to oestrogen receptor β (ERβ). Expression of ERβ is found reduced in tumour tissue and inversely related to mortality. However, mechanisms are not well understood. Our study aimed to detect differentially methylated genes associated with ERβ expression, which could point to mechanisms by which ERβ could influence risk and prognosis of CRC. Epigenome-wide DNA methylation profiling was performed using Illumina HumanMethylation450k BeadChip arrays in two independent tumour sample sets of CRC patients recruited in 2003-2010 by the German DACHS study (discovery cohort n = 917, replication cohort n = 907). ERβ expression was measured using immunohistochemistry and scored as negative, moderate and high. Differentially methylated CpG sites and genomic regions were determined using limma in the R-package RnBeads. For the comparison of tumours with moderate/high ERβ versus negative expression, differentially methylated CpG sites were identified but not confirmed by replication. Comparing tumours of high with tumours of negative ERβ expression revealed 2,904 differentially methylated CpG sites of which 403 were replicated (FDR adjusted p-value<0.05). Replicated CpGs were annotated to genes such as CD36, HK1 or LRP5. A survival analysis indicates that 30 of the replicated CpGs are also associated with overall survival (FDR-adjusted p-value<0.05). The regional analysis identified 60 differentially methylated promotor regions. The epigenome-wide analysis identified both novel genes as well as genes already implicated in CRC. Follow-up mechanistic studies to better understand the regulatory role of ERβ could inform potential targets for improving treatment or prevention of CRC.
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http://dx.doi.org/10.1080/15592294.2019.1595998DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6557594PMC
May 2019

The Association Between Mutations in BRAF and Colorectal Cancer-Specific Survival Depends on Microsatellite Status and Tumor Stage.

Clin Gastroenterol Hepatol 2019 02 13;17(3):455-462.e6. Epub 2018 Apr 13.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.

Background & Aims: Colorectal tumors with mutations in BRAF and microsatellite stability (MSS) have been associated with adverse outcomes of patients. Combined tests for microsatellite instability-high (MSI-H) and BRAF mutations might therefore be used in risk assessment, particularly for patients with stage II tumors. We investigate the stage-specific prognostic value of combined testing for MSI-H and BRAF for patients with colorectal cancer.

Methods: We performed a retrospective analysis of colorectal tumor samples collected from 1995 patients at 22 hospitals in Germany, between 2003 and 2010. Samples were analyzed for MSI-H using an established mononucleotide marker panel; BRAF mutations (BRAFV600E) were detected by Sanger sequencing or in tissue microarray blocks using immunohistochemistry. Cancers were assigned to categories of having MSS without mutations in BRAF, MSS with mutant BRAF, MSI-H without mutations in BRAF, and MSI-H with mutant BRAF. We investigated the association between tumor categories with clinical and pathologic features and patient's overall, disease-specific, and recurrence-free survival (median follow-up time, 5.1 y).

Results: Tumors were stage I in 364 (18%), stage II in 678 (34%), stage III in 673 (34%), and stage IV (14%) in 280 patients. Sixty-three percent of tumors were located in the colon and 37% in the rectum. Most tumors (85%) had MSS without mutations in BRAF, 3% had MSS with mutant BRAF, 7% had MSI-H without mutations in BRAF, and 5% had MSI-H with mutant BRAF. In patients whose tumors were MSI-H, mutation of BRAF did not significantly affect survival time. Patients whose tumors had MSS with mutant BRAF had significantly reduced overall survival (hazard ratio [HR], 2.16; 95% CI, 1.54-3.04; P < .001), disease-specific survival (HR, 2.59; 95% CI, 1.77-3.79; P < .001), and recurrence-free survival (HR, 2.45; 95% CI, 1.70-3.52; P < .001) than patients whose tumors had MSS without BRAF mutation. Although BRAF mutations in tumors with MSS were associated with disease-specific survival of patients with stage III or IV tumors (P < .001), these features did not affect survival of patients with stage II tumors (P = .639).

Conclusions: In an analysis of almost 2000 patients with colorectal cancer, we found BRAF mutations to reduce survival of patients in stage III or IV (but not stage II) tumors with MSS. These findings do not support testing stage I or II colorectal tumors for BRAF mutations, although additional large studies are needed.
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http://dx.doi.org/10.1016/j.cgh.2018.04.015DOI Listing
February 2019

Associations Between Molecular Classifications of Colorectal Cancer and Patient Survival: A Systematic Review.

Clin Gastroenterol Hepatol 2019 02 3;17(3):402-410.e2. Epub 2018 Jan 3.

Division of Clinical Epidemiology and Aging Research, Heidelberg, Germany. Electronic address:

Background & Aims: Colorectal cancer (CRC) is a heterogeneous disease with different mechanisms of pathogenesis. Classification systems have been proposed based on molecular features of tumors, but none are used in clinical practice. We performed a systematic review of studies on the associations between molecular classifications of CRC and patient survival.

Methods: We searched the PubMed, Embase, Cochrane, and Web of Science databases for combinations of terms related to CRC, molecular markers, subtype classifications, and survival (overall survival, disease-specific survival, disease-free survival). We included only studies that used at least 3 molecular markers to classify tumors and provided an estimate of survival associated with each subtype. Data extraction and quality assessment were performed independently by 2 reviewers.

Results: We identified 6 studies that fulfilled the inclusion criteria. In these studies, molecular subtypes were assigned based on pathways associated with tumor development or findings from gene expression clustering analyses. Most studies proposed classification systems with 5 subtypes, including information on microsatellite instability, mutations in BRAF, and mutations in KRAS. None of the studies included TNM stage in their classification system. Three classification systems used similar definitions. Only 3 studies provided internal or external validation of the proposed classification schemes. Tumors with microsatellite stability and mutations in KRAS or BRAF were associated with decreased survival times, compared with tumors with microsatellite stability and no mutations.

Conclusions: In a systematic review of studies of molecular classifications of CRC and patient survival, we found that most subtypes were not significantly or not differentially associated with survival. None of the systems integrated TNM staging. Further research and validation are needed to develop molecular subtype classification systems for clinical practice.
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http://dx.doi.org/10.1016/j.cgh.2017.12.038DOI Listing
February 2019

High-dose-rate brachytherapy delivered in two fractions as monotherapy for low-risk prostate cancer.

J Contemp Brachytherapy 2015 Feb 4;7(1):10-6. Epub 2015 Feb 4.

Centro de Control de Cancer Ltda., Bogota, Colombia.

Purpose: High-dose-rate (HDR) brachytherapy has been accepted as an effective and safe method to treat prostate cancer. The aim of this study was to describe acute toxicity following HDR brachytherapy to the prostate, and to examine the association between dosimetric parameters and urinary toxicity in low-risk prostate cancer patients.

Material And Methods: Patients with low-risk prostate cancer were given HDR brachytherapy as monotherapy in two 12.5 Gy fractions. Planning objectives for the planning target volume (PTV) were V100% ≥ 90% and V150% ≤ 35%. Planning objectives for organs at risk were V75% ≤ 1 cc for the bladder, rectum and perineum, and V125% ≤ 1 cc for the urethra. Toxicity was assessed three months after treatment using the Common Terminology Criteria for Adverse Events.

Results: Seventy-three patients were included in the analysis. Thirty-three patients (45%) reported having any type of toxicity in the three months following HDR brachytherapy. Most toxicity cases (26%) were grade 1 urinary toxicity. Mean coverage index was 0.89 and mean V100 was 88.85. Doses administered to the urethra were associated with urinary toxicity. Patients who received more than 111.3% of the prescribed dose in 1 cc of the urethra were four times more likely to have urinary toxicity compared to patients receiving less than 111.3% (OR = 4.71, 95% CI: 1.43-15.6; p = 0.011).

Conclusions: High-dose-rate brachytherapy administered as monotherapy for prostate cancer proved to be a safe alternative treatment for patients with low-risk prostate cancer. Urinary toxicity was associated with the dose administered to 1 cc and 0.1 cc of the urethra and was remarkably inferior to the reported toxicity in similar studies.
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http://dx.doi.org/10.5114/jcb.2015.48838DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4371062PMC
February 2015
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