Heterogeneity in colorectal cancer incidence among people recommended 3-yearly surveillance post-polypectomy: a validation study

Abstract

Background Colonoscopy surveillance is recommended for patients at increased risk of colorectal cancer (CRC) following adenoma removal. Low-, intermediate-, and high-risk groups are defined by baseline adenoma characteristics. We previously examined intermediate-risk patients from hospital data and identified a higher-risk subgroup who benefited from surveillance and a lower-risk subgroup who may not require surveillance. This study explored whether these findings apply in individuals undergoing CRC screening. Methods This retrospective study used data from the UK Flexible Sigmoidoscopy Screening Trial (UKFSST), English CRC screening pilot (ECP), and US Kaiser Permanente CRC prevention program (KPCP). Screening participants (50 – 74 years) classified as intermediate-risk at baseline colonoscopy were included. CRC data were available through 2006 (KPCP) or 2014 (UKFSST, ECP). Lower- and higher-risk subgroups were defined using our previously identified baseline risk factors: higher-risk participants had incomplete colonoscopies, poor bowel preparation, adenomas ≥ 20 mm or with high-grade dysplasia, or proximal polyps. We compared CRC incidence in these subgroups and in the presence vs. absence of surveillance using Cox regression. Results Of 2291 intermediate-risk participants, 45 % were classified as higher risk. Median follow-up was 11.8 years. CRC incidence was higher in the higher-risk than lower-risk subgroup (hazard ratio [HR] 2.08, 95 % confidence interval [CI] 1.07 – 4.06). Surveillance reduced CRC incidence in higher-risk participants (HR 0.35, 95 %CI 0.14 – 0.86) but not statistically significantly so in lower-risk participants (HR 0.41, 95 %CI 0.12 – 1.38). Conclusion As previously demonstrated for hospital patients, screening participants classified as intermediate risk comprised two risk subgroups. Surveillance clearly benefited the higher-risk subgroup.

A single‐center retrospective study comparing 1‐day and 3‐day low‐residue diets for bowel preparation

“…Screening programs that utilize either fecal immunochemical tests or colonoscopies provide the best opportunity to prevent disease and reduce mortality 3–6 . Adequate bowel preparation is an indispensable component of a high‐quality colonoscopy because suboptimal cleansing leaves residue that can obscure precancerous lesions, 7–9 which may eventually lead to interval colorectal cancers 10–12 . In addition, inadequate bowel preparation potentially increases the burden on surveillance programs 12,13 …”

“…colonoscopy because suboptimal cleansing leaves residue that can obscure precancerous lesions, [7][8][9] which may eventually lead to interval colorectal cancers. [10][11][12] In addition, inadequate bowel preparation potentially increases the burden on surveillance programs. 12,13 The current international guidelines 14,15 for optimal bowel preparation recommend a low-residue diet (LRD), split-dose laxatives, and oral simethicone before the procedure.…”

“…[10][11][12] In addition, inadequate bowel preparation potentially increases the burden on surveillance programs. 12,13 The current international guidelines 14,15 for optimal bowel preparation recommend a low-residue diet (LRD), split-dose laxatives, and oral simethicone before the procedure. However, a consensus on the best timing and duration of the LRD has not been achieved.…”