Polyp surveillance after surgery for colorectal cancer.
OBJECTIVE
Although it is known that those patients who have developed colorectal cancer (CRC) are at a higher risk to develop metachronous adenoma or CRC, no study has been performed to analyze the relationship between the risk factors and the time course for the formation of postoperative adenoma using survival analysis.


METHODS
One hundred seventy-six patients with CRC,who had received surgical resection, were endoscopically followed-up to detect the development of metachronous adenoma or adenocarcinoama. The association between the risk factors such as age, synchronous adenomas with index CRC or other clinicopathological variables and the formation of postoperative adenoma was assessed using the logrank test and the Cox proportional hazard model.


RESULTS
Age over 60, synchronous lesions at the time of surgery for primary CRCs and presence of diabetes mellitus(DM) as the associated disease were positively related to the formation of postoperative adenoma. Among those patients with the three risk factors, only 27.8% remained adenoma-free during 5 years after operation, whereas in the group without any risk factor, it was 90.4%.


CONCLUSIONS
From our data, age over 60, synchronous adenomas or CRCs and DM were the potential risk factors for the postoperative formation of adenoma or CRC, and they should be taken into consideration when defining the appropriate interval of postoperative colonoscopy.
Department of Surgical Oncology, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. kz-kawai@mvd.biglobe.ne.jp
Kazushige
K
Kawai
Eiji
E
Sunami
Nelson H
NH
Tsuno
Joji
J
Kitayama
Toshiaki
T
Watanabe
D000236:Adenoma / Q000175:diagnosis / Q000473:pathology; D003111:Colonic Polyps / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011159:Population Surveillance; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors