Predictive Factors for Malignant Potential in Colorectal Polyps in Korea

Kim, Chang Seop; Rhee, Poong Lyul; Kim, Young Ho; Son, Hee Jung; Kim, Jae Jun; Shim, Sang Goon; Lee, Hwa Young; Park, Sang Jong; Park, Jung Ho; Park, Hyung Suk; Bae, Sang Su; Chun, Jung Hak; Koh, Kwang Cheol; Paik, Seung Woon; Rhee, Jong Chul; Choi, Kyoo Wan; Kim, Seon Woo

Abstract

BACKGROUND/AIMS: The aim of this study was to investigate predictive factors for malignant transformation of colorectal adenomatous polyps in Korea.
METHODS
One thousand five hundred and eighty- nine sessions of colonoscopic polypectomy were performed from November 1994 to September 1998 for 1,375 patients with adenomatous polyps at Samsung Medical Center. We analyzed the 2,179 adenomatous polyps including 55 (2.5%) polyps with malignant transformation, retrospectively.
RESULTS
Six parameters showed significant differences in univariate (p<0.01) and multivariate analysis. For each parameter, the proportions of malignant polyps were as follows: for number of polyps, 1.3% in cases of single polyp and 10.3% in cases of multiple polyps; for size, 1.4% of polyps less than 1 cm and 15.5% of polyps larger than 1 cm; for location, 4.6% of the polyps located in rectum or sigmoid colon and 1.1% of the polyps located in descending to ascending colon; for morphology, 0.9% in polyps of Yamada type I/II and 7.6% in polyps of Yamada type III/IV; for underlying histology, 1.4% in cases of tubular adenoma and 8.1% in cases of tubulovillous or villous adenoma; for degree of dysplasia, 1.2% in cases accompanied with low-grade dysplasia and 8.9% in cases accompanied with high-grade dysplasia.
CONCLUSIONS
The malignant potential of colorectal adenomatous polyps in Korea is correlated with multiplicity, distal location, pedunculated shape as well as well-known factors like size, histologic type and degree of dysplasia.