Colorectal Cancer Surveillance
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Direct answer
What was removed dictates when you return: the post-polypectomy intervals of the United States Multi-Society Task Force assign one or two small tubular adenomas to a 7–10-year return, three to four to 3–5 years, five or more adenomas or any adenoma of 10 mm or more to 3 years, and more than ten adenomas to under 3 years — with piecemeal resection of a sessile or serrated lesion of 10 mm or more bringing the patient back at 6 months for a scar check. After curative colorectal cancer resection, colonoscopy at one year is the rule (three and five years if normal thereafter), alongside CEA and cross-sectional imaging per protocol. The inherited and inflammatory syndromes compress the clock: Lynch syndrome colonoscopy every 1–2 years from age 20–25, inflammatory bowel disease beginning 8 years after diagnosis of extensive disease, and primary sclerosing cholangitis demanding annual colonoscopy from the time of PSC diagnosis.
What you must remember
- USMSTF 2020 backbone: 1–2 tubular adenomas under 10 mm — 7–10 years; 3–4 such adenomas — 3–5 years; 5–10 adenomas or any adenoma 10 mm or larger — 3 years; more than 10 adenomas — under 3 years; tubulovillous or villous histology and high-grade dysplasia shorten intervals to 3 years; serrated lesions of 10 mm or more, serrated lesions with dysplasia, and traditional serrated adenomas earn 3 years.
- The 6-month rule: piecemeal endoscopic resection of sessile or serrated lesions of 10 mm or more requires early repeat with scar examination — recurrence at the cautery line is the specific risk, and tattooing of the site is what makes the revisit possible.
- Post-cancer-resection schedule: clearing colonoscopy perioperatively or within 3–6 months if obstructed (or CT colonography at 1 year with colonoscopy if positive), then colonoscopy at 1 year, 3 years and 5 years if each is normal; CEA every 3–6 months for 2 years and cross-sectional imaging (CT chest-abdomen-pelvis) annually for 3 years in higher-risk patients complete the protocol.
- Lynch syndrome: germline MLH1, MSH2, MSH6, PMS2 or EPCAM mutation carriers — colonoscopy every 1–2 years from age 20–25 (or 2–5 years before the earliest family cancer if earlier); universal or selective tumour screening by mismatch-repair immunohistochemistry and microsatellite-instability testing finds the families.
- IBD clock: surveillance begins 8 years after symptom onset for extensive colitis (and left-sided disease on many protocols), repeated every 1–5 years by risk; primary sclerosing cholangitis starts annual surveillance at PSC diagnosis and continues post-transplant; chromoendoscopy with targeted biopsies outperforms random quadratic mapping.
- Familial adenomatous polyposis: flexible sigmoidoscopy annually from age 10–12 in at-risk families, converting to surveillance or colectomy pathways once adenomas appear; MUTYH-associated polyposis follows a slightly later, less dense programme.
- Incomplete or inadequate examinations: an unreadable bowel preparation shortens the next interval to within a year, and an examination that never reached the caecum is a study that did not happen.
A worked surveillance pathway
A 55-year-old undergoes screening colonoscopy: Boston preparation 8, caecum photographed, and three lesions removed — a 4 mm sigmoid tubular adenoma, an 8 mm adenoma snared intact, and a 14 mm sessile serrated lesion removed piecemeal in the transverse colon with a tattoo placed. The 6-month rule attaches to the piecemeal 14 mm serrated lesion, so the return visit is at 6 months for scar assessment; if that is clean, the subsequent interval is 3 years, set by the serrated lesion of 10 mm or more — the binding constraint among the findings. Had the same patient instead undergone a sigmoid colectomy for a pT3N1 cancer, the schedule would be perioperative clearing, colonoscopy at 1 year, 3 years, then 5 years, with CEA and CT layered on. The examiner's craft is exactly this arithmetic: finding the lesion that sets the interval, and knowing the one exception that overrides everything.
Where students slip
The common slips: assigning 3 years to a single 6 mm tubular adenoma (over-surveillance — 7–10 years is correct); forgetting the 6-month piecemeal rule; treating a serrated lesion as if it were an adenoma of no consequence; and confusing the IBD clock (8 years from symptoms, immediately annual with PSC) with the Lynch clock (from age 20–25). Post-resection, candidates quote 3 years as the first colonoscopy — the answer is 1 year, with the 3-year and 5-year studies following normal results. The Indian viva adds the real-world question of cost: guidelines are minimum-standard maps, and intervals are stratified by risk, not by what a family can pay.
Frequently asked questions
What surveillance follows removal of one small tubular adenoma?
A 7–10-year interval, shared with average-risk screening, because a single sub-centimetre tubular adenoma barely raises subsequent risk.
When must colonoscopy be repeated at 6 months?
After piecemeal resection of a sessile or serrated lesion of 10 mm or more, to inspect the resection scar for residual tissue — with the site tattooed at the index procedure.
What is the colonoscopy schedule after curative colorectal cancer resection?
Colonoscopy at 1 year, then 3 years, then every 5 years if normal, with CEA every 3–6 months for 2 years and annual cross-sectional imaging in higher-risk patients.
How is Lynch syndrome surveillance structured?
Colonoscopy every 1–2 years from age 20–25, or 2–5 years before the earliest family diagnosis, continued lifelong because of the accelerated adenoma-carcinoma transition.
When does inflammatory bowel disease surveillance begin and at what frequency?
Eight years after symptom onset for extensive colitis (15 years for left-sided disease on some protocols), then every 1–5 years stratified by risk — annually and immediately with primary sclerosing cholangitis.