[Polyps with an invasive degenerated focus].

Advances in technology of flexible endoscopes have greatly changed the management of patients with adenomatous polyps of the colon and rectum. Some controversy still exists concerning the best treatment for invasive polyps. For some authors, invasive polyps need radical operation, while others think that unless cancer goes beyond the bounds of a removed polyp, endoscopic resection is an adequate procedure. We designed a study of 65 patients presenting an invasive carcinoma arising in adenomatous polyps and who underwent a colorectal resection thereafter, in order to determine which endoscopic and histological features correlated best with a curative treatment by polypectomy. When the group of "non-curative polypectomies", (carcinoma in the surgical specimen: 34 patients) was compared to the group of "curative polypectomies" (carcinoma in the surgical specimen: 31 patients), there was no significant difference in the number of pedunculated or sessile polyps but a polyp's size exceeding 30 mm was significantly more frequent in the group of "non-curative polypectomies" (P less than 0.005) as well as a tubulo-villous or villous histological type (P less than 0.001) and presence of vascular neoplastic invasion (P less than 0.01). In conclusion, a surgical resection after endoscopic polypectomy of a polyp containing an invasive carcinoma is necessary for a polyp's size exceeding 30 mm, for a villous or tubulo-villous type and in the presence of vascular neoplastic invasion in the pathological analysis of the removed polyp.