Clinicopathological Characteristics and Malignant Potential of Colonic Flat Adenomas Compared to That of Polypoid Adenomas

Jee, Myeong Gwan; Kim, Hyun Soo; Kim, Won Ho; Kim, Tae Il; Park, Dong Il; Kim, Young-Ho; Kim, Hyo Jong; Byeon, Jeong-Sik; Yang, Suk-Kyun; Lee, Moon Sung; Jung, Il Kwon; Jung, Sung-Ae; Jeen, Yoon Tae; Choi, Jai Hyun; Choi, Hwang; Choi, Kyu Yong; Han, Dong Soo

Original Article

Intestinal Research 2005;3(2):127-132.
Published online December 30, 2005.

Clinicopathological Characteristics and Malignant Potential of Colonic Flat Adenomas Compared to That of Polypoid Adenomas

Myeong Gwan Jee, Hyun Soo Kim, Won Ho Kim, Tae Il Kim, Dong Il Park, Young-Ho Kim, Hyo Jong Kim, Jeong-Sik Byeon, Suk-Kyun Yang, Moon Sung Lee, Il Kwon Jung, Sung-Ae Jung, Yoon Tae Jeen, Jai Hyun Choi, Hwang Choi, Kyu Yong Choi, Dong Soo Han

^*Department of Internal Medicine, Yonsei University Wonju College of Medicine
^†Wonju, Yonsei University College of Medicine
^‡Seoul, Sungkyunkwan University College of Medicine
^§Seoul, Kyunghee University College of Medicine
^∥Seoul, Ulsan University College of Medicine
^¶Seoul, Soonchonhyang University College of Medicine
^**Bucheon and Cheonan, Ewha Woman's University College of Medicine
^††Seoul, Korea University College of Medicine
^‡‡Seoul and Ansan, The Catholic University of Korea, College of Medicine
^§§Incheon, Hanyang University College of Medicine, Guri, Korea

대장 폴립형 선종과 비교한 편평 선종의 임상 및 병리학적 특성과 악성화 빈도

지명관, 김현수, 김원호, 김태일, 박동일, 김영호, 김효종, 변정식, 양석균, 이문성, 정일권, 정성애, 진윤태, 최재현, 최황, 최규용, 한동수

^*연세대학교 원주의과대학
^†연세대학교 의과대학
^‡성균관대학교 의과대학
^§경희대학교 의과대학
^∥울산대학교 의과대학
^¶순천향대학교 의과대학
^**이화여자대학교 의과대학
^††고려대학교 의과대학
^‡‡가톨릭대학교 의과대학
^§§한양대학교 의과대학 내과학교실

Abstract

Background/Aims
Colorectal flat adenomas have been a topic of debate in the view of malignant potential. The aims of this study are to investigate the clinicopathological features of flat adenomas compared to that of polypoid adenomas and to identify the determinants for malignant transformation in colorectal flat and polypoid adenomas. Methods: This was a prospective, cross sectional study of 3,360 patients who diagnosed as adenomas via total colonoscopy and polypectomy at 13 tertiary medical centers between July 2003 and July 2004. Potential risk factors for malignant transformation were analyzed. Results: Out of 3,360 adenomas, 207 (6.2%) were flat adenomas and 3,153 (93.8%) were polypoid adenomas. The patients with flat adenoma were older (59.6 vs. 57.1, p＜0.01) and more frequently located in the right colon than polypoid adenomas (49.3% vs. 32.0%, p<0.01). The incidence of high grade dysplasia or cancer in flat adenomas was similar to that of polypoid adenomas (5.4% vs. 4.6%, p=0.36). Multivariate analysis revealed that the size ≥11 mm (OR 6.8; 95% CI 4.8-9.7) and location of adenoma in the left colon (OR 1.6; 95% CI 1.07-2.38) were significant determinants for malignant potential of colonic adenoma. Conclusions: Clinicopathological determinants for malignant potential in colorectal adenomas were not gross morphology but size and location of adenoma. (Intestinal Research 2005;3:127-132)

Key Words: Flat adenoma, Polypectomy, Colonoscopy, Malignant potential