Colonoscopy Surveillance After Colorectal Cancer: the Optimal Interval for Follow-Up

Patients who have undergone curative surgery for colorectal cancer are at risk of developing a metachronous colorectal tumour or anastomotic recurrence. The aim of this study was to determine the incidence of recurrent colorectal cancer in a cohort of patients who participated in a colonoscopy surveillance programme.

This single-centre retrospective observational cohort study included patients who underwent curative surgery for colorectal cancer between 2005 and 2015. All reports of postoperative colonoscopies were retrieved to calculate the incidence rates of recurrence and metachronous colorectal cancer.

Of 2420 patients, 1644 (67.9%) underwent at least one postoperative colonoscopy and 776 (32.1%) did not. In 1087 patients, colonoscopy was performed in the first 18 months after surgery, which detected 34 (3.1%) instances of metachronous colorectal tumours or anastomotic recurrence. Thirty-three additional patients were also diagnosed with recurrent colorectal cancer, but the tumours were detected by other diagnostic modalities or detected perioperatively, rather than by colonoscopy.

Patients with a history of colorectal cancer have an increased risk for a second colorectal tumour. Therefore, we recommend a colonoscopic surveillance programme with the first colonoscopy performed 1 year after curative surgery, which is in accordance with national guidelines.