Impact of Guideline-Concordant Post-Polypectomy Colonoscopy Surveillance on Colorectal Cancer Incidence and Mortality

Impact of exposure to guideline-concordant post-polypectomy surveillance colonoscopy on colorectal cancer (CRC) risk is uncertain. We aimed to determine whether follow-up concordant with post-polypectomy surveillance guidelines is associated with reduced CRC incidence and mortality.

We conducted a retrospective case-cohort study among United States Veterans who underwent colonoscopy with polyp removal between 1999 and 2016 across 128 health care systems. The primary predictor was concordance status with surveillance colonoscopy guidelines, assessed as a binary time-varying variable. Time to incident and fatal CRC was investigated using multivariable weighted Cox regression adjusting for key baseline characteristics, with risk summarized using adjusted hazard ratios (HRs).

From a cohort of 516,058 individuals with baseline polypectomy, we included 685 individuals with incident CRC, 233 individuals with fatal CRC, and a random subsample of 1530 individuals. At baseline, median age was 63 years (interquartile range, 58-68 years); 97.3% were male; and 32.6% had an advanced polyp. Exposure to guideline concordant follow-up was associated with a 78% relative reduction for incident CRC risk over 9730 person-years follow-up (HR, 0.22; 95% confidence interval, 0.16-0.31). Guideline concordant follow-up was not associated with reduced fatal CRC risk over 8224 person-years follow-up (HR, 0.96; 95% confidence interval, 0.49-1.87). A large proportion of incident (55.2%) and fatal (39.5%) CRC events occurred within 4 years of baseline colonoscopy.

Follow-up concordant with post-polypectomy surveillance guidelines is associated with reduced risk of incident CRC, but impact on risk of fatal CRC requires further study. Many post-polypectomy CRC events occur early in the surveillance window, underscoring importance of baseline colonoscopy quality in influencing post-polypectomy CRC risk.