Postpolypectomy colonoscopy surveillance may be unnecessary in patients with low or intermediate risk for colorectal cancer (CRC). The findings from this retrospective study were published in GI Cancer.
Investigators from the Department of Surgery and Cancer at University College London, United Kingdom, investigated current CRC prevention guidelines and CRC incidences along with the effects of surveillance among each CRC risk group.
The study incorporated data from 28,972 patients who underwent colonoscopy with adenoma removal at 17 hospitals in the United Kingdom. This patient cohort was separated on the basis of number and size of adenomas into low (n=14,401; median age, 64 years; 56% male), intermediate (n=11,852; median age, 66 years; 56% male), and high (n=2719; median age, 67 years; 71% male) risk of developing CRC. All patients were followed (median follow-up time, 9.3 years), and CRC incidence was assessed within the groups and compared with the general population.
The investigators reported that the CRC incidence was 40% to 50% lower in the patient cohort that had a single colonoscopy vs those patients who did not. The hazard ratios for each group were 0.56 (95% confidence interval [CI], 0.39-0.80), 0.59 (95% CI, 0.43-0.81), and 0.49 (95% CI 0.29-0.82) for the low-, intermediate-, and high-risk groups, respectively.
Although a reduction in CRC was reported overall, the standardized incidence ratios were similar between the general population and low-risk (0.86; 95% CI, 0.73-1.02) or intermediate-risk (1.16; 95% CI, 0.97-1.37) patient groups. For the high-risk group, the study reported that incidence of CRC was similar between patients who did not receive surveillance, at 5.7% (95% CI, 4.0%-8.3%), and those who had a single follow-up, at 5.6% (95% CI, 3.1%-9.8%), but CRC incidence dropped in the subset of patients who received 2 colonoscopy screenings, at 2.6% (95% CI, 1.5%-4.4%).
This study was limited by its follow-up time. Not all cases of CRC develop in less than 10 years after adenoma removal, and it is unclear from this report whether colonoscopies should be recommended at a longer time scale.
The authors concluded that patients with low, and some with intermediate, risk for CRC had similar rates as the general population, and as colonoscopies can cause adverse effects, additional postpolypectomy surveillance should not be recommended. The authors suggested that this group of patients should be benignly screened by a fecal immunochemical test instead. Patients with high risk, however, should be screened by more than one colonoscopy.
Cross AJ, Robbins EC, Pack K, et al. Long-term colorectal cancer incidence after adenoma removal and the effects of surveillance on incidence: a multicentre, retrospective, cohort study [published online January 17, 2020]. GI Cancer. doi:10.1136/gutjnl-2019-320036