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Post-polypectomy surveillance after piecemeal endoscopic mucosal resection — ABIM Board MCQ

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HardColorectal CancerPost-polypectomy surveillance after piecemeal endoscopic mucosal resectionABIM Board

A 59-year-old woman underwent a high-quality screening colonoscopy that identified a 26-mm nonpedunculated ascending-colon lesion. The lesion was removed by piecemeal endoscopic mucosal resection. Histopathology showed a tubular adenoma with low-grade dysplasia and no invasive carcinoma. No other polyps were found. Surveillance colonoscopy 6 months later showed a well-healed resection scar without visible residual tissue; targeted biopsy specimens were negative for adenoma. A second surveillance colonoscopy 1 year after that examination again showed no local recurrence or metachronous polyps. She has no family history of colorectal cancer, hereditary colorectal cancer syndrome, or inflammatory bowel disease. Which of the following is the most appropriate timing of her next colonoscopy?

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Correct answer: B — Repeat colonoscopy in 3 years

Explanation lettering: B = shown as A · E = shown as B · A = shown as E

The next colonoscopy should be performed in 3 years. Piecemeal resection of a colorectal adenoma at least 20 mm in size has a higher risk of residual or recurrent neoplasia than en bloc resection and therefore triggers a specific sequential surveillance schedule. The US Multi-Society Task Force recommends the first surveillance colonoscopy approximately 6 months after resection, the second 1 year after the first surveillance examination, and the third 3 years after the second surveillance examination. This patient has completed the first two examinations without recurrence, so the third examination is now due in 3 years. A 6-month interval (A) applies to the first examination after the index piecemeal resection. A 1-year interval (B) applies between the first and second surveillance examinations. A 2-year interval (C) is not part of the recommended sequence and should not be substituted by counting from the original resection date. A 5-year interval (D) would prematurely de-escalate surveillance despite the original lesion's size and piecemeal removal. The absence of high-grade dysplasia or invasive carcinoma does not eliminate the intensified schedule because the decisive factors are lesion size of at least 20 mm and piecemeal resection.

Reference: Recommendations for Follow-Up After Colonoscopy and Polypectomy: A Consensus Update by the US Multi-Society Task Force on Colorectal Cancer (2020) — https://www.asge.org/home/resources/publications/guidelines/recommendations-for-follow-up-after-colonoscopy-and-polypectomy-a-consensus-update-by-the-us-multi-society-task-force-on-colorectal-cancer Recommendations for follow-up after colonoscopy and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer (2020) — https://pmc.ncbi.nlm.nih.gov/articles/PMC7389642/