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Polyps, adenomas and colorectal cancer risk

Wed, 03/18/2020 - 11:46
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Patients with polyps have a higher risk of colorectal cancer and those with sessile serrated polyps, tubulovillous adenomas and villous adenomas have a higher colorectal cancer mortality, according to a study, ‘Risk of colorectal cancer incidence and mortality after polypectomy: a Swedish record-linkage study’, published in The Lancet Gastroenterology & Hepatology.

To prevent subsequent cancer, individuals diagnosed with either conventional adenomas or sessile serrated polyps by screening endoscopy are advised to undergo colonoscopy surveillance at different intervals, depending on the most advanced findings of the index endoscopy. However, existing guidelines for colonoscopy surveillance vary widely and lack sufficient evidence

In a matched nationwide cohort study in Sweden using individual level data from the ESPRESSO study linked to nationwide health registers for the period 1993-2016, researchers from Karolinska Institutet, Harvard TH Chan School of Public Health and Massachusetts General Hospital examined the risk of colorectal cancer in patients with 178,377 different types of polyps and 864,831 matched reference individuals.

The ten-year cumulative incidence of colorectal cancer was 1.6% (95% CI 1.5–1.7) for hyperplastic polyps, 2.7% (2.5–2.9) for tubular adenomas, 2.5% (1.9–3.3) for sessile serrated polyps, 5.1% (4.8–5.4) for tubulovillous adenomas and 8.6% (7.4–10.1) for villous adenomas, compared with 2.1% (2.0–2.1) in reference individuals.

"The study provides detailed subtype-level data for the risk of colorectal cancer following polypectomy. The findings highlight the importance of close surveillance for patients with certain subtypes of polyps," said first author and lead investigator, Dr Mingyang Song, Massachusetts General Hospital.

Compared with reference individuals, patients with any polyps had an increased risk of colorectal cancer, with multivariable HR of 1.11 (95% CI 1.02–1.22) for hyperplastic polyps, 1.77 (1.34–2.34) for sessile serrated polyps, 1.41 (1.30–1.52) for tubular adenomas, 2.56 (2.36–2.78) for tubulovillous adenomas and 3.82 (3.07–4.76) for villous adenomas.

Risk of colorectal cancer in patients with polyps representing villous adenoma (Credit: Karolinska Institutet)
Risk of colorectal cancer in patients with polyps representing villous adenoma (Credit: Karolinska Institutet)

“In conclusion, patients with any polyp subtype had a higher risk of colorectal cancer incidence than the reference individuals in this largely screening-naive population. The risk elevation increased with advanced histology for both conventional adenomas and serrated polyps,” the authors concluded. “In contrast, the risk of colorectal cancer mortality was increased only in patients with sessile serrated polyps, tubulovillous adenomas, or villous adenomas. Our findings suggest that patients with any of the latter three lesions might benefit from colonoscopy surveillance.”

"Our results indicate that patients with sessile serrated polyps, tubulovillous adenomas, and villous adenomas might benefit from surveillance, but further studies are needed to examine the impact of colonoscopy surveillance on prevention of colorectal cancer,” said senior author and Karolinska Institutet, Professor Jonas F Ludvigsson.

To access this study, please click here