Local recurrence and its risk factors after cold snare polypectomy of colorectal polyps.

Background: Local recurrence after cold snare polypectomy (CSP) of colorectal polyps has not been well analyzed. In this study, we analyzed the characteristics of local recurrence.
Methods: We retrospectively reviewed consecutive lesions resected by CSP from 2014 to 2016 and lesions that were followed up at ≥ 10 months after CSP, were analyzed. Our indication for CSP was a benign tumor of < 15 mm in size. We analyzed local recurrence and its risk factors using multivariate analyses. In addition, we compared lesions of ≥ 10 mm and < 10 mm. Moreover, therapeutic methods for recurrence were analyzed.
Results: Finally, we analyzed 554 cases out of 820 consecutive cases. The mean polyp size was 5.3 ± 2.8 mm and the en bloc resection and histopathological complete resection rates were 99.3% and 70.2%, respectively. The overall recurrence rate was 1.9% (mean follow-up period: 13.0 ± 4.0 months). Significant differences were observed between 11 recurrent lesions and 543 lesions without recurrence regarding polyp size (8.0 ± 3.7 mm vs. 5.2 ± 2.7 mm, p < 0.001), rate of sessile-serrated polyp (27.3% vs. 3.0%, p < 0.001), and histopathological positive margin (45.4% vs. 3.7%, p = 0.019). Multivariate analyses showed that a histopathological positive margin was the only significant risk factor for local recurrence (OR 16.600, 95% CI 3.707-74.331, p < 0.001). Regarding the comparison between 74 lesions of ≥ 10 mm and 480 lesions of < 10 mm, significant differences were observed in the en bloc resection rate (93.2% vs. 100%, p < 0.001), high-grade dysplasia rate (8.1% vs. 0.8%, p < 0.001), and histopathological complete resection rate (54.0% vs. 72.7%, p = 0.001). The recurrence rates of these two groups were 5.4% and 1.4%, respectively (p = 0.069). All recurrent cases could be resected with repeat CSP.
Conclusions: The local recurrence rate after CSP for lesions of < 10 mm was 1.4%. CSP was not recommended for lesions of ≥ 10 mm due to high rates of recurrence and malignancy.