Medium-large polyps of the colon: a contribution for their clinical profile and a proper surveillance.

A retrospective analysis of polypoid lesions of the colon larger than 1 cm was performed with the aim to study their characteristics and a proper surveillance schedule. We reviewed all colon polypoid lesions larger than 1 cm found and treated during the period January 1984- December 1993 that were not considered cancer macroscopically. The records of 361 patients with 391 polyps are the object of this report. The polyps were divided into subgroups according to size: A) less than 20 mm, B) between 21 and 30 mm, and C) larger than 30 mm. Out of 391 polypoid lesions 373 were adenomas: 60% were found in males. The age group distribution showed no differences among the subgroups. The pedunculated type showed a decrease from 69.1% to 43.3% with the increasing of size: inverse figures were observed for sessile polyps. The lesions were mainly located in left colon. Synchronous adenomas were found in 25.4% patients, and metachronous and previous adenomas respectively in 24.8% and 5.2%: no significant difference was present in the subgroups. Synchronous malignancy in the colon was found in 2% of the patients. Histological characteristics demonstrated a decrease of tubular adenoma from 46.5% to 22.6% from subgroup A to C, while villous adenomas increased inversely from 6.6% to 15.1%. The presence of severe dysplasia ranged from 20.9% to 56.1% in subgroups A and C, respectively, and adenomas with invasive cancer showed a significant increase from the subgroup A to C, respectively from 4.3% to 10.5%. During an average 36-month follow-up we observed 2 metachronous colon cancers, surgically treated in Dukes stage B, 84 metachronous adenomas, all less than 10 mm and without malignant alterations. Our data confirm other literature reports regarding the profile of colon adenomas with an increasing risk of malignancy with the increase of size and the presence of villous structure. In our opinion the assessment of a "clean colon" status is important when an adenoma is found in the colon. The proper follow-up for adenomas must be tailored for any individual patient when risk factors such as size, villous structure, personal and family history of neoplastic lesions of the colon are present. The follow-up schedule, presently recommended for colon adenomas, must be flexible according to these parameters.