Prospective Evaluation of Colorectal Polyps in 1,683 Consecutive Colonoscopies / 대한소화기내시경학회지

ABSTRACT

BACKGROUND AND AIMS: The colorectal polyp, particularly the adenoma, has been regarded as a precursor of cancer. The incidence of colorectal polyps has been reported at various rates according to investigation centers in foreign countries. In Korea, the incidence of colorectal polyps has been reported as very low according to the few reports, which was involved a few cases and were partial. Therefore, the aim of this study is to evaluate prospectively the incidence and the clinicopathologic features of colorectal polyps. METHODS: A colonoscope was inserted up into the cecum in 1,889 patients among 2,001 trials from Oct. 1996 to Aug. 1997 (success rate 94.4%). Of the 1,889 full colonoscopies, the following were excluded; 1) referred patients with suspicious colorectal cancer or polyps, 2) patients with suspicious rectal cancer determined by rectal examination, 3) patients who had follow-up colonoscopy after a polypectomy or cancer surgery, and 4) patients who had periodic colonoscopy due to FAP or HNPCC. There were a total of 1,683 full colonoscopies in this study. The majority of the total cases involved a colonoscopy due to benign anal disease, irritable bowel syndrome, or routinechecks for health. RESULTS: There were 946 men (56.2%) and 737 women (43.8%). The mean age was 48.2 yrs (13~88 yrs) for men and 48.1 yrs (18~89 yrs) for women. 422 patients were found to have 645 colorectal polyps (1.52 polyps per patient). The incidence of polyps was 25.1% (32.0% for men, 16.1% for women) and increased after the 6th decade in men (44.0%) and in women (23.0%). 281 patients were found to have 426 colorectal adenomas. The incidence of adenomas was 16.6% (21.9% for men, 9.9% for women) and increased after the 6th decade, 32.0% in men, and 15.9% in women. Solitary polyps were present in 277 patients (65.6%) while 94 patients (22.3%) had two polyps and 51 patients (12.1%) had between 3 and 8 polyps. The polyp retrieval rate was 96.9%. There were 426 adenomas (66.0%), 75 hyperplastic (11.7%), 120 inflammatory (18.6%), and 24 miscellaneous (3.7%) polyps. Of the 426 adenoma, there were 397 tubular adenoma (93.2%), 18 tubulovillous adenoma (4.3%), 4 villous adenoma (0.9%), 6 in situ carcinoma (1.4%), and 1 invasive carcinoma (0.2%). 6 in situ carcinoma's were detected in tubular adenoma and 1 invasive carcinoma in tubulovillous adenoma. Of 645 polyps, the sessile type was 87.9%. The polyp size varied from 1 mm to 25 mm and 79.2% were under 5mm. Also, 85.7% of adenomas were sessile and 74.7% were under 5mm. 22.0% of polyps were located in rectum, 35.4% in sigmoid colon, 9.5% in descending colon, 13.3% in transverse colon, 19.8% in ascending colon and cecum. The distribution of adenoma was similar to that of polyp. 40.1% of adenoma showed moderate to severe dysplasia. CONCLUSIONS: This study revealed that the incidence of polyp in Korea was higher than that in previous reports and 42.6% of polyps were proximal to rectosigmoid colon. Therefore, we suggest that we should try to detect and remove colorectal polyps by more active colonoscopy.