Follow-up colonoscopy in patients with colorectal adenomatous polyps

Forty-four asymptomatic patients with adenomatous colorectal polyps were followed by repeated colonoscopies and subsequent removal of new polyps. The median follow-up time was 34 months (range, 4 to 131 months). Twenty-six patients (59 percent) developed new adenomatous polyps. Therecurrence rate was 69 percent in patients with multiple polyps compared with 54 percent in patients with a single polyp. The location of new polyps was in the same colonic segment in 81 percent of the patients, but not at the same site in the colon where a previous polyp had been removed. The histopathology and size of new polyps compared with the initial polyps showed a significant improvement in histopathology toward more benign polyps (P<0.02) and smaller polyps (P<0.001). In patients who initially had single adenomatous polyps, new polyp(s) were diagnosed after a mean time of 23 months compared initially. Patients with atypia in initial polyp(s) developed new polyp(s) after a mean time of 11 months compared with 23 months in patients without atypia. The mean time from a colon with no polyps to the diagnosis of a new adenomatous polyp less than 5 mm in size was 11.5 months, which was a statistically significant shorter time than the 19.4 months observed for the development of polyps 5 mm or larger.