Bariatric Surgery Prior to Index Screening Colonoscopy Is Associated With a Decreased Rate of Colorectal Adenomas in Obese Individuals

Abstract

Objectives:Obesity is an important risk factor for the development of colorectal cancer (CRC). Although the impact of bariatric surgery on CRC is conflicting, its impact on precursor lesions is unknown. The aim of this study was to determine whether bariatric surgery before index screening colonoscopy is associated with decreased development of colorectal adenomas.Methods:We performed a retrospective cohort study of bariatric surgery patients who had undergone index, screening colonoscopy at an academic center from 2001 to 2014. Patients who had bariatric surgery at least 1 year before index colonoscopy were compared with those who had surgery after colonoscopy, using multivariable logistic regression to control for presurgical body mass index, sex, gender, race, type of surgery, aspirin use, metformin use, smoking, and age at colonoscopy.Results:One hundred and twenty-five obese individuals who had bariatric surgery before colonoscopy were compared with 223 individuals who had colonoscopy after surgery. Adenomatous polyps were found in 16.8% of individuals who had surgery first vs. 35.5% who had colonoscopy before bariatric surgery (unadjusted odds ratio (OR) 0.37, 95% confidence interval (CI): 0.21–0.64, P=0.0003). After multivariable adjustment, bariatric surgery before index screening colonoscopy was associated with a decreased risk of adenomas at index colonoscopy (adjusted OR 0.37, 95% CI: 0.19–0.69, P=0.002).Conclusions:Bariatric surgery is associated with a decreased risk of colorectal adenomas in obese individuals without a family history of CRC.

Weight Change and Incident Distal Colorectal Adenoma Risk in the PLCO Cancer Screening Trial

“…Previous observational studies did not observe an association between weight loss and adenoma risk ( 12 , 14 , 15 ). However, our findings are consistent with a study that observed a lower likelihood of adenoma following bariatric surgery ( 19 ), suggesting a beneficial effect of weight loss on adenoma risk in an initially obese population.…”

Increasing changes in visceral adiposity is associated with higher risk for colorectal adenoma: Multilevel analysis in a prospective cohort

“…Kedrin et al suggested that morbidly obese patients who underwent bariatric surgery have a decreased risk of colorectal adenomas in a retrospective cohort study. 19 This finding implies that a change in body fat mass may bring about significant health benefits in terms of colorectal adenoma occurrence, whereas the author could not differentiate VAT from SAT. We demonstrated a greater role of increasing changes in VAT or SAT over their baseline values.…”

“…This study took a further step into looking at the longitudinal change in visceral and subcutaneous adiposity. Kedrin et al suggested that morbidly obese patients who underwent bariatric surgery have a decreased risk of colorectal adenomas in a retrospective cohort study 19 . This finding implies that a change in body fat mass may bring about significant health benefits in terms of colorectal adenoma occurrence, whereas the author could not differentiate VAT from SAT.…”

Role of bariatric surgery in reducing the risk of colorectal cancer: a meta-analysis

“…They reported lower rectal crypt cell proliferation, reduced systemic and mucosal markers of inflammation, and improvement in glucose regulation, which are all consistent with reduced markers of tumorigenic potential. To assess whether this reduction in the tumorigenic potential following bariatric surgery extended to colonic polyps (precursors to the majority of endoluminal colorectal malignancies), Kedrin and colleagues compared findings in 125 obese patients who had bariatric surgery before colonoscopy with those in 223 patients who had colonoscopy after surgery. The rate of adenomatous polyps in the patients who had colonoscopy after surgery was more than double that of patients who had surgery first (35·5 versus 16·8 per cent respectively; odds ratio 0·37, 95 per cent c.i.…”