[Colonic adenoma: risk factors for their malignant transformation].

BACKGROUND

Almost all colorectal cancers develop from adenomatous polyp, its detection and resection prevent the malignization. Several adenoma characteristics like: number, size, morphology, histologic type and grade of dysplasia have become considered as malignization risk factors.

AIMS

This study was designed to determine the frequency of colorectal adenoma and the principal risk factors for malignization.

METHODS

Between June of 1989 and July of 1994, 846 colonoscopies were performed and retrospectively analyzed in the same number of patients. The patients with colorectal polyps were chosen for the analysis of this study as well all the polyps characteristics, to determine the risk factors for malignization.

RESULTS

There were 183 patients (21.6%) with 322 colorectal polyps. Of all of them, only 214 (66.4%) underwent colonoscopy snare resection and were studied; 120 (57%) were neoplastic polyps and 94 (43%) non neoplastic; among those neoplastic polyps, 100 (83.4%) were tubular adenomas, 11 (9.1%) were tubulovillous adenomas, and 9 (7.5%) were villous adenomas. We found 16 (7.4%) polyps with adenocarcinoma, 14 (87.5%) were found in patients older than 50 years of age and in polyps larger than 1 cm in diameter (p 0.040). Eleven (68.7%) were sessiles (p 0.001).

CONCLUSIONS

After the evaluation of polyps, the tubular adenomas were the neoplastic polyps more frequently found. In this particular study, the patient age, polyp size and morphology were the more statistically significant risk factors for malignization in our patient group.