The first year follow-up after colorectal adenoma polypectomy is important: a multiple-center study in symptomatic hospital-based individuals in China.

The recurrence of colorectal adenoma (CRA) is high. Although there are guidelines for colonoscopy surveillance after polypectomy in other countries, little is known about its recurrence rate and recurrence peak, especially in China. The aim of the present research is to investigate how long after polypectomy follow-up should take and to analyze risk factors of recurrence. 1208 patients who received polypectomies from five clinical research centers in four regions of China (Shanghai, Guangzhou, Nanjing and Beijing) were included. They were divided into 4 groups: group A (follow-up ≤ 1 year after polypectomy), group B (follow-up 2-3 years after polypectomy), group C (follow-up 4-5 years after polypectomy), and group D (follow-up > 5 years after polypectomy). The sex, age, adenoma location, size, number, and pathological characteristics were compared. On the whole, the recurrence rate was 59.46% in group A, 61.09% in group B, 78.07% in group C, and 87.12% in group D, which indicated an increased tendency with a prolonged follow-up duration. There was a significant difference between group A and C or D, and between group B and C or D (P<0.01), but there was no statistical difference between group A and B. Additionally, the recurrent patients in the first year had a recurrence rate of 97.33% in the first three years (59.46/61.09), which means that the peak of recurrence was almost entirely concentrated in the first year. The recurrence rate was higher in males and the elder. The risk factors included multiple numbers, villous feature, high-grade dysplasia of medium or smaller size and location in the distal colon. In conclusion, the peak of recurrence was almost totally concentrated in the first year; meanwhile, the first year follow-up is of critical importance in China. It may not be necessary to do the follow-up examination during the second and third years, but after three years, another colonoscopy should be undertaken.