Association of second surveillance colonoscopy findings with index and first surveillance colonoscopy results

Although there have been established guidelines for first surveillance colonoscopy (FSC) after a polypectomy, there is no consensus on performing a second surveillance colonoscopy (SSC), especially in Asian countries. This study aimed to investigate the association of SSC findings with index total colonoscopy (TCS) and FSC results.

This was a single-center retrospective cohort study involving 1928 consecutive Japanese patients who had received three or more colonoscopies. High-risk colonoscopic findings were defined as advanced adenoma (≥10 mm in size, with a villous histology or high-grade dysplasia) or more than three adenomas, whereas low-risk findings were defined as one to two non-advanced adenomas. On the basis of index TCS results, the patients were divided into three groups: no adenomas (NA) (n = 888), low-risk (LR) (n = 476), and high-risk (HR) (n = 564) groups, respectively.

In the NA group, the rate of high-risk findings on SSC was significantly higher in patients with high-risk or low-risk findings on FSC than in those with no adenoma (7.7% and 7.9% vs 2.2%, P < 0.05). Patients in the LR and HR groups with high-risk findings on FSC had a significantly higher risk on SSC than those with low-risk findings or no adenoma on FSC (LR group: 28.6%, 9.4%, and 5.9%, respectively, P < 0.01; HR group: 34.5%, 18.8%, and 7.9%, respectively, P < 0.01).

Index TCS and especially FSC findings were predictive of SSC results. The study results may be useful for determining appropriate intervals for surveillance colonoscopy in Asian countries.