Surveillance Colonoscopies of Synchronous Colorectal Cancer: What Should We Do?

The aim of this study is to investigate the occurrence of metachronous neoplasms at 2-year surveillance colonoscopy for synchronous colorectal cancer patients and the relative risk factors.

Synchronous colorectal cancer patients who underwent surgery or endoscopic resection for colorectal cancer between January 2008 and December 2019 were enrolled. All patients underwent surveillance colonoscopies at least twice within 2 years after operation. Univariate and multivariate analyses were conducted to assess the risk factors for the metachronous neoplasms.

Totally 38 patients (male/female: 26/12) were included, with an average age of 64.6 years (±11.5 years) and a mean surveillance interval of 23.47 ± 4.39 months. In 21 of 38 patients (55.3%), metachronous adenoma was detected, including 6 metachronous advanced adenomas. Two patients were detected with metachronous carcinomas. In univariate analysis, male sex, elderly age at diagnosis, and the presence of synchronous adenomas/synchronous advanced adenoma at baseline colonoscopy were associated with the development of metachronous adenoma (P = .037, .047, .013, .039), but not associated with metachronous advanced adenoma (P = 0.455, .746, .503, .269). Patients tends to occur less metachronous advanced adenoma if index colorectal tumors were treated by endoscopic resection (P = .010), but the tendency was not discovered in metachronous adenoma (P = .289). Tumor location (with/ without rectum cancer) was not associated with the development of metachronous lesions (P = .526, .382). On multivariate analysis, the presence of synchronous adenomas at baseline colonoscopy was an independent risk factor for MA during follow-up (odds ratio = 15.0; 95% CI: 1.55-145.22).

For postoperative synchronous colorectal cancer patients, doctors should design individual surveillance strategies according to sex, baseline colonoscopy, and operative (or endoscopic) approach of resection.