Publications by authors named "Mark S Johnstone"

4 Publications

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Novel Methods of Risk Stratifying Patients for Metachronous, Pre-Malignant Colorectal Polyps: A Systematic Review.

Crit Rev Oncol Hematol 2021 Jul 9;164:103421. Epub 2021 Jul 9.

Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, United Kingdom.

Introduction: Despite conventional measures of future polyp risk (histology, dysplasia, size, number), surveillance places a burden on patients and colonoscopy services. We aimed to review novel risk stratification techniques.

Methods: A systematic literature review was performed for studies using genomics, transcriptomics, IHC or microbiome as markers of metachronous polyp risk.

Results: 4165 papers underwent title, 303 abstract and 215 full paper review. 25 papers were included. 49 mutations/ SNPs/ haplotypes in 23 genes/ chromosomal regions (KRAS, APC, EGFR, COX1/2, IL23R, DRD2, CYP2C9/24A1/7A1, UGT1A6, ODC, ALOX12/15, PGDH, SRC, IGSF5, KCNS3, EPHB1/ KY, FAM188b, 3p24.1, 9q33.2, 13q33.2) correlated with metachronous adenoma / advanced adenoma risk. Expression levels of 6 proteins correlated with metachronous adenoma (p53, β-catenin, COX2, Adnab-9, ALDH1A1) or sessile serrated polyp (ANXA10) risk.

Conclusion: Although genomic and IHC markers correlated with metachronous polyp risk, it seems likely that a panel of novel markers will be required to refine this risk.
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July 2021

The Relationship Between Co-morbidity, Screen-Detection and Outcome in Patients Undergoing Resection for Colorectal Cancer.

World J Surg 2021 07 27;45(7):2251-2260. Epub 2021 Mar 27.

Academic Unit of Surgery, University of Glasgow, New Lister Building, Glasgow Royal Infirmary, 8-16 Alexandra Parade, Glasgow, G31 2ER, UK.

Background: Bowel cancer screening increases early stage disease detection and reduces cancer-specific mortality. We assessed the relationship between co-morbidity, screen-detection and survival in colorectal cancer.

Methods: A retrospective, observational cohort study compared screen-detected (SD) and non-screen-detected (NSD) patients undergoing potentially curative resection (April 2009-March 2011). Co-morbidity was quantified using ASA, Lee and Charlson Indices. Systemic inflammatory response was measured using the neutrophil lymphocyte ratio (NLR). Covariables were compared using crosstabulation and the χ2 test for linear trend. Survival was analysed using Cox Regression.

Results: Of 770 patients, 331 had SD- and 439 NSD-disease. A lower proportion of SD patients had a high ASA (≥3) compared to NSD (27.2% vs 37.3%; p = 0.007). There was no significant difference in the proportion of patients with a high (≥2) Lee Index (16.3% SD vs 21.9% NSD; p = 0.054) or high (≥3) Charlson Index (22.7% SD vs 26.9% NSD; p = 0.181). On univariate analysis, NSD (HR 2.182 (1.594-2.989;p < 0.001)), emergency presentation (HR 3.390 (2.401-4.788; p < 0.001)), advanced UICC-TNM (III or IV) (p < 0.001), high ASA (≥3) (HR 1.857 (1.362-2.532; p < 0.001)), high Charlson Index (≥3) (HR 1.800 (1.333-2.432; p < 0.001)) and high (≥3) NLR (HR 1.825 (1.363-2.442; p < 0.001)) were associated with poorer overall survival (OS). NSD predicted poorer cancer-specific survival (CSS) (HR 2.763 (1.776-4.298; p < 0.001)). On multivariate analysis, NSD retained significance as an independent predictor of poorer OS (HR 1.796 (1.224-2.635; p = 0.003)) and CSS (HR 1.924 (1.193-3.102; p = 0.007)).

Conclusions: Patients with SD cancers have significantly lower ASA scores. After adjusting for ASA, co-morbidity and a broad range of covariables, SD patients retain significantly better OS and CSS.
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July 2021

Analysis of lesion localisation at colonoscopy: outcomes from a multi-centre U.K. study.

Surg Endosc 2017 07 8;31(7):2959-2967. Epub 2016 Nov 8.

Department of Surgery, Royal Alexandra Hospital, Corsebar Road, Paisley, PA2 9PN, Scotland, UK.

Background: Colonoscopy is currently the gold standard for detection of colorectal lesions, but may be limited in anatomically localising lesions. This audit aimed to determine the accuracy of colonoscopy lesion localisation, any subsequent changes in surgical management and any potentially influencing factors.

Methods: Patients undergoing colonoscopy prior to elective curative surgery for colorectal lesion/s were included from 8 registered U.K. sites (2012-2014). Three sets of data were recorded: patient factors (age, sex, BMI, screener vs. symptomatic, previous abdominal surgery); colonoscopy factors (caecal intubation, scope guide used, colonoscopist accreditation) and imaging modality. Lesion localisation was standardised with intra-operative location taken as the gold standard. Changes to surgical management were recorded.

Results: 364 cases were included; majority of lesions were colonic, solitary, malignant and in symptomatic referrals. 82% patients had their lesion/s correctly located at colonoscopy. Pre-operative CT visualised lesion/s in only 73% of cases with a reduction in screening patients (64 vs. 77%; p = 0.008). 5.2% incorrectly located cases at colonoscopy underwent altered surgical management, including conversion to open. Univariate analysis found colonoscopy accreditation, scope guide use, incomplete colonoscopy and previous abdominal surgery significantly influenced lesion localisation. On multi-variate analysis, caecal intubation and scope guide use remained significant (HR 0.35, 0.20-0.60 95% CI and 0.47; 0.25-0.88, respectively).

Conclusion: Lesion localisation at colonoscopy is incorrect in 18% of cases leading to potentially significant surgical management alterations. As part of accreditation, colonoscopists need lesion localisation training and awareness of when inaccuracies can occur.
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July 2017

Improving lesion localisation at colonoscopy: an analysis of influencing factors.

Int J Colorectal Dis 2015 Jan 7;30(1):111-8. Epub 2014 Nov 7.

School of Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.

Purpose: Colonoscopy detects colorectal cancer and determines lesion localisation that influences surgical planning. However, published work suggests that the accuracy of lesion localisation can be low as 60%, with implications for both the surgeon and the patient. This work aims to identify potential influencing factors at colonoscopy that could lead to improved lesion localisation accuracy.

Methods: A multi-centred, prospective, observational study was performed that identified patients who were undergoing planned curative resection for a colorectal lesion. Localisation of a lesion at colonoscopy was compared to the intra-operative lesion localisation to determine accuracy of colonoscopic localisation. Patient factors and colonoscopic factors were recorded to determine any influencing factors on lesion localisation at colonoscopy.

Results: One hundred and eleven patients were analysed: mean age 67.4 years (range 27-89); male:female ratio 1.3:1; symptomatic referrals (n = 78, 70.3%); and previous abdominal surgery in 27 patients (24.3%). Complete colonoscopy was recorded in 78 patients (70.3%). In 88 patients (79.3%), colonoscopic lesion localisation matched the intra-operative location. Pre-operative CT imaging was unable to identify the tumour in 24 cases (21.8%). Potential influencing patient and colonoscopic factors on accurate lesion localisation at colonoscopy found complete colonoscopy to be the only significant factor (p = 0.008).

Conclusion: Colonoscopic lesion localisation was found to be inaccurate in 79.3% cases, and with pre-operative CT unable to detect all lesions, this study confirms that accurate lesion localisation in the modern era is increasingly reliant on colonoscopy. Incomplete colonoscopy was the only significant factor that influenced inaccurate lesion localisation at colonoscopy.
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January 2015