Risk factors for recurrence of colorectal conventional adenoma and serrated polyp

BACKGROUND: Removal of colorectal polyps during screening could reduce the incidence of colorectal cancer (CRC). However, there is a lack of data on risk factors associated with recurrence of polyps, including conventional adenomas and serrated polyps (SPs). This study aimed to determine risk factors for recurrence of colorectal polyps and their subtypes based on the characteristics of the patients and polyps. METHODS: A total of 1,165 patients diagnosed with conventional adenoma or SP in the Sixth Affiliated Hospital of Sun Yat-sen University between January 2013 and December 2019 were enrolled in this study, including 668 cases with conventional adenomas, 385 with SPs, and 112 with coexistence of adenomas and SPs. Univariate analysis and multivariate logistic regression were used to identify potential risk factors for polyp recurrence. A nomogram was established according to risk factors and the performance was evaluated using calibration plots. RESULTS: During a median follow-up of 24 months, recurrent polyps were observed in 531 (45.6%) cases. Male, age ≥50 years, body mass index (BMI) ≥24 kg/m(2), at least three polyps, smoking, alcohol consumption, family history of polyps, and family history of CRC were independent risk factors for polyp recurrence. The Harrell’s C-index of the nomogram developed with these parameters was 0.69 and the calibration plots showed good agreement between actual polyp recurrence and nomogram-predicted recurrence probability. In the subtype analyses, conventional adenomas had the same risk factors for recurrence as all polyps, while smoking, alcohol consumption, family history of polyps, and family history of CRC were not risk factors for SP recurrence. CONCLUSIONS: We identified several risk factors for recurrence of colorectal polyps and found that some of them could increase the risk of adenoma recurrence but not SP recurrence, including smoking, alcohol consumption, and family history of polyps/CRC, which might help us to understand different etiology and biology between conventional adenomas and SPs.