Transanal treatment of rectal cancer: ablative methods and open resection.

Conservative surgical techniques are an alternative to radical surgery for selected patients with rectal carcinoma. The goals of conservative management are to select patients with low risk for nodal metastases and achieve local tumor control while preserving anal sphincter function. Patient selection is critical to achieve this outcome because properly selected patients can obtain results comparable to radical surgery. Selection is based on preoperative histologic characteristics and endorectal ultrasonography. Predictors of pelvic lymph node metastasis risk include tumor grade, depth of penetration, mucinous features, and vascular and lymphatic invasion. Endorectal ultrasound (ERUS) is important in accurately staging the lesion by identifying both depth of invasion and presumptive nodal status. The options for local therapy reviewed include techniques of full-thickness local excision and ablative procedures including endocavitary irradiation, electrocoagulation, and laser therapy. The techniques of full-thickness transanal excision and endocavitary irradiation are described with results from the University of Minnesota experience.