Review of recurrent polyps and cancer in 500 patients with initial colonoscopy for polyps

Five hundred patients with 1240 polyps removed by colonoscopy and polypectomy over a 13-year period are the subject of ongoing follow-up study. Ninety-three percent of the patients have been followed an average of 53 months with a recurrence rate of polypoid disease in 26 percent, of which approximately 7 percent demonstrated malignant changes. This compares to a rate of 7 percent metachronous cancer in patients with a malignancy demonstrated at any time in the past. The highest risk group for recurrence are patients with more than four polyps at initial colonoscopy, with a 59 percent recurrence rate. The following recommendations for follow-up are made: 1) Flexible sigmoidoscopy is adequate yearly follow-up if the original polyps are confined to the rectum and sigmoid. 2) Colonoscopy should be carried out the first year if the original polyps are beyond the rectum and sigmoid, and yearly until the colon is cleared of recurring lesions. 3) Colonoscopy is indicated in patients with cancer before surgery if possible; if not, within six months after resection. 4) Interval six-month examinations are indicated in patients with colon cancer and multiple synchronous polyps until the colon is cleared. 5) Large, sessile polyps resected piecemeal require a three-month follow-up until gone. 6) When the above conditions are met, colonoscopy at three-year intervals is adequate for long-term follow-up of neoplastic polyps to detect and prevent early malignancy.