Prise en charge des cancers superficiels du rectum

Superficial rectal cancers consist of Tis and T1 tumors as defined by the TNM classification system. Earlier detection of colorectal cancers through endoscopic screening should lead to an increase in the percentage of superficial cancers detected while still superficial; they may eventually represent more than a third of diagnosed rectal cancers. Endorectal ultrasound, ideally performed with a mini-probe, is the best pre-operative study to define the level of penetration into the rectal wall; depth of penetration and grade of differentiation are the major factors to be considered when contemplating local excision as an alternative to radical resection. Local excision can be performed endoscopically or by the classic transanal surgical approach. Each technique has pros and cons and the two are often complementary. Compared to the alternative of radical proctectomy, they have the decided advantages of zero mortality, minimal morbidity, and decreased expense. Pathologic examination of the resected specimen is the final determinant as to whether local resection is adequate therapy. When histologic prognostic factors are favorable (well-differentiated, absence of lymphatic or vascular invasion, superficial invasion of the submucosa (sm1), and clear resection margins), the risk of lymph node spread is negligible. When histologic prognostic factors are not favorable, a completion radical proctectomy should be performed.