Screening Colonoscopy and Risk for Incident Late-Stage Colorectal Cancer Diagnosis in Average-Risk Adults

Abstract

Background The effectiveness of screening colonoscopy in average-risk adults is uncertain, particularly for right colon cancers. Objective Examine the association between screening colonoscopy and incident late-stage colorectal cancer (CRC) risk. Design Nested case-control study. Setting Four U.S. health plans Patients Average-risk adults with ≥5 years of enrollment in one of the health plans (n=1,039). Cases were 55–85 years old on their diagnosis date (reference date) of stage ≥IIB (late-stage) CRC during 2006–2008. We selected 1–2 controls for each case, matched on birth year, gender, health plan, and prior enrollment duration. Measurements Receipt of CRC screening between 3 months and up to 10 years before the reference date, ascertained through medical record audits. We compared cases and controls on receipt of screening colonoscopy or sigmoidoscopy using conditional logistic regressions that accounted for health history, socioeconomic status and other screening exposures. Results In analyses restricted to 471 eligible cases and their matched controls (n=509), 13 cases (2.8%) and 46 controls (9.0%) had undergone screening colonoscopy, which corresponded to an adjusted odds ratio (AOR) of 0.30 (95% confidence interval [CI]: 0.15–0.59) for any late-stage CRC, 0.37 (CI: 0.16–0.82) for right colon cancers, and 0.26 (CI: 0.06–1.11) for left-sided colon/rectum cancers. Ninety-two cases (19.5%) and 173 controls (34.0%) underwent screening sigmoidoscopy, corresponding to an AOR of 0.51 (CI: 0.36–0.71) overall, 0.80 (CI: 0.52–1.25) for right colon late-stage cancers, and 0.26 (CI: 0.14–0.49) for left colon/rectum cancers. Limitations The small number of screening colonoscopies affected the precision of our estimates. Conclusions Screening with colonoscopy in average-risk persons was associated with reduced risk of diagnosis with incident late-stage CRC in both the right colon and left colon/rectum. For sigmoidoscopy, this association was observed for left-sided CRC, but the association for right colon late-stage cancer was not statistically significant. Primary Funding Source National Cancer Institute of the National Institutes of Health.

Expected long-term impact of the German screening colonoscopy programme on colorectal cancer prevention: Analyses based on 4,407,971 screening colonoscopies

“…Several randomised trials have demonstrated major reduction of distal colorectal cancer (CRC) incidence by screening with flexible sigmoidoscopy [1][2][3][4], and observational studies suggest a large potential for even stronger reduction of (proximal and distal) CRC incidence by screening colonoscopy [5][6][7]. The trials also indicate, however, that it may often take many years until screening effects become fully manifest.…”

Incidence of Colorectal Adenomas: Birth Cohort Analysis among 4.3 Million Participants of Screening Colonoscopy

“…Various screening methods have been proposed and shown to be effective in randomized trials and observational studies, including fecal occult blood testing, sigmoidoscopy, and colonoscopy (3)(4)(5)(6)(7). However, there is an ongoing debate about the most effective screening programs in terms of important screening features, such as type of screening test, age at first screening, screening, and surveillance intervals.…”

Predicting Non-Adherence with Outpatient Colonoscopy Using a Novel Electronic Tool that Measures Prior Non-Adherence

“…1 Colonoscopy can reduce CRC-related mortality by up to 90 %, and is costeffective. [2][3][4][5][6] Despite clear benefits, screening colonoscopy is underutilized, and rates of non-adherence with scheduled colonoscopy and flexible sigmoidoscopy are high, ranging from 5 to 40 %. [7][8][9][10][11][12] Consistent identification of patients at risk for non-adherence with scheduled colonoscopy is a critical first step towards improving adherence.…”