Microscopic Colitis Is Associated With a Reduced Risk of Colorectal Adenoma and Cancer: A Meta-Analysis

Background The study sought to conduct a systematic review and meta-analysis of the risk of colorectal adenoma or cancer in patients with microscopic colitis (MC). Methods A comprehensive literature search of PubMed and EMBASE databases was performed. Pooled relative risks (RRs) and 95% confidence intervals (CIs) were calculated to examine the effect of MC on the risk of colorectal adenoma or cancer. Results Twelve studies reporting the outcomes of 50 795 patients with MC were eligible for this meta-analysis. MC was negatively associated with the risk of colorectal adenoma compared with participants without MC (RR, 0.44; 95% CI, 0.33-0.58; P < .001; I2 = 87.3%). Also, the rate of colorectal cancer was lower in the patients with MC compared with the general population (RR, 0.62; 95% CI, 0.43-0.89; P = .01; I2 = 91.6%). In addition, sensitivity and subgroup analyses indicated that the results were robust. Conclusions The present systematic review indicated that patients with MC may be associated with a lower risk of colorectal adenoma or cancer. The clinical data support the current professional society guideline. A surveillance colonoscopy program is not recommended as standard for patients with MC.

The impact of cumulative colorectal cancer screening delays: A simulation study

Objective Annual fecal immunochemical tests can reduce colorectal cancer incidence and mortality. However, screening is a multi-step process and most patients do not perfectly adhere to guideline-recommended screening schedules. Our objective was to compare the reduction in colorectal cancer incidence and life-years gained based on US guideline-concordant fecal immunochemical test screening to scenarios with a range of delays. Method The Colorectal Cancer Simulated Population model for Incidence and Natural history (CRC-SPIN) microsimulation model was used to estimate the effect of systematic departures from fecal immunochemical test screening guidelines on lifetime screening benefit. Results The combined effect of consistent modest delays in screening initiation (1 year), repeated fecal immunochemical test screening (3 months), and receipt of follow-up or surveillance colonoscopy (3 months) resulted in up to 1.3 additional colorectal cancer cases per 10,000, 0.4 additional late-stage colorectal cancer cases per 10,000 and 154.7 fewer life-years gained per 10,000. A 5-year delay in screening initiation had a larger impact on screening effectiveness than consistent small delays in repeated fecal immunochemical test screening or receipt of follow-up colonoscopy after an abnormal fecal immunochemical test. The combined effect of consistent large delays in screening initiation (5 years), repeated fecal immunochemical test screening (6 months), and receipt of follow-up or surveillance colonoscopy (6 months) resulted in up to 3.7 additional colorectal cancer cases per 10,000, 1.5 additional late-stage colorectal cancer cases per 10,000 and 612.3 fewer life-years gained per 10,000. Conclusions Systematic delays across the screening process can result in meaningful reductions in colorectal cancer screening effectiveness, especially for longer delays. Screening delays could drive differences in colorectal cancer incidence across patient groups with differential access to screening.

Effect of diminutive adenoma with high-grade dysplasia on surveillance colonoscopy interval

Background Colonoscopy surveillance guidelines set the surveillance schedule based on polyp characteristics. Polyps with high-grade dysplasia (HGD) require 3 years of follow-up regardless of size. However, it is unclear whether patients with diminutive polyps (≤5 mm) with HGD have a higher risk. We evaluated the effect of diminutive adenoma with HGD on adenoma occurrence. Methods From Jan 2015 to Dec 2017, patients who underwent index and surveillance colonoscopy were retrospectively screened. The patients were grouped into no adenoma group, low-risk (patients with ≤2 low-grade dysplasia (LGD)), diminutive HGD and high-risk (HGD >5 mm, ≥3 adenomas) groups according to the index colonoscopy results. Each group was analyzed using logistic analysis. Results The mean follow-up period was 22.47 months. Altogether, 610 (50.45%) patients had LGD and 152 (12.5%) had HGD. Among them, 61(5.0%) patients had a diminutive polyp with HGD. Analysis of the risks of developing advanced adenoma in the surveillance colonoscopy showed that compared to no adenoma group, the diminutive HGD group did not show a significant risk (odds ratio [OR]=1.503 [0.449–5.027], p=0.509), while the high-risk group showed a significant risk (odds ratio [OR]=2.044 [1.015–4.114], p=0.045). Conclusions Diminutive adenoma with HGD increased the risk of adenoma on surveillance colonoscopy, In the case of advanced adenoma, the risk was increased, but it was not statistically significant.

Hybrid endoscopic mucosal resection and full-thickness resection for large colonic polyps harboring a small focus of invasive cancer: a case series

Endoscopic treatment of large laterally spreading tumors (LSTs) with a focus of submucosally invasive colorectal cancer (T1 CRC) can be challenging. We evaluated outcomes of a hybrid resection technique using piecemeal endoscopic mucosal resection (pEMR) and endoscopic full-thickness resection (eFTR) in patients with large colonic LSTs containing suspected T1 CRC. Six hybrid pEMR-eFTR procedures for T1 CRCs were registered in a nationwide eFTR registry between July 2015 and December 2019. In all cases, the invasive part of the lesion was successfully isolated with eFTR; with eFTR, histologically complete resection of the invasive part was achieved in 5 /6 patients (83.3 %). No adverse events occurred during or after the procedure. The median follow-up time was 10 months (range 6–27), with all patients having undergone ≥ 1 surveillance colonoscopy. One patient had a small adenomatous recurrence, which was removed endoscopically. In conclusion, hybrid pEMR-eFTR is a promising noninvasive treatment modality that seems feasible for a selected group of patients with large LSTs containing a small focus of T1 CRC.