• Local transanal or other resection with or without perioperative external-beam irradiation plus fluorouracil (5-FU). There are no randomized trials comparing local excision with or without postoperative chemoradiation treatments to wide surgical resection (LAR and APR). One prospective multicenter phase II study and several larger retrospective series suggest that well-staged patients with small (<4 centimeters) tumors with good histologic prognostic features (well- to moderately-differentiated adenocarcinomas), mobile, and no lymphatic, venous, or perineural invasion, treated with full-thickness local excision that results in negative margins may have outcomes equivalent to APR or LAR with the selective post-operative use chemoradiation therapy.. Endoscopic ultrasound studies have been helpful in defining these patients. Patients with tumors that are pathologically T1 may not need postoperative therapy. Patients with tumors that are T2 or greater have lymph node involvement of 20% or more and require additional therapy, such as radiation and chemotherapy, or more standard surgical resection. Patients with poor histologic features should consider LAR or APR and postoperative treatment as dictated by full surgical staging. The selection of patients for local excision may also be improved by newer imaging techniques, such as endorectal magnetic resonance imaging and endorectal ultrasound.

Patients with cT2N0 distal rectal cancer do not require adjuvant therapy. However, when a patient refuses an abdominoperineal resection (APR), is there an alternative? The German CAO/ARO/AIO 94 preoperative versus postoperative rectal trial reported that the incidence of sphincter preservation in those patients who were judged clinically by the operating surgeon to require an APR was significantly increased in the preoperative (39%) versus postoperative arm (20%). Since patients enrolled in that trial had either cT3, T4, and/or N+ disease, combined-modality therapy was necessary for adjuvant therapy. In this report, we present the rates of sphincter preservation and function, toxicity, local control, and survival following preoperative pelvic radiation and selective postoperative chemotherapy in patients with distal cT2N0 rectal cancer who refused an APR.

The purpose of this trial is to determine whether preoperative external-beam radiation therapy can increase the rate of sphincter preservation for patients with distal cT2N0 adenocarcinoma of the rectum. Between April 1988 and October 2003, 27 patients with distal rectal adenocarcinoma staged T2 by clinical and/or endorectal ultrasound who were judged by the operating surgeon to require an APR were treated with preoperative pelvic radiation alone (50.4 Gy). Surgery was performed 4 to 7 weeks later. If pathologic positive pelvic nodes were identified, postoperative adjuvant chemotherapy was recommended. The median follow-up was 55 months (range, 9 to 140 months).

The pathologic complete response rate was 15% and 78% of patients underwent a sphincter-sparing procedure. The crude incidence of local failure for patients undergoing a sphincter sparing procedure was 10% and the 5-year actuarial incidence was 13%. The actuarial 5-year survival for patients undergoing sphincter preservation was as follows: disease-free, 77%; colostomy-free, 100%; and overall, 85%. Using the Memorial Sloan-Kettering Cancer Center sphincter function score, 54% of those undergoing a sphincter-sparing procedure had good/excellent bowel function at 12 to 24 months after surgery, and 77% had good/excellent function at 24 to 36 months after surgery. Our data suggest that for patients with cT2N0 distal rectal cancer who require an APR, preoperative pelvic radiation improves sphincter preservation without an apparent compromise in local control or survival.

Whole pelvic field. The lateral borders were 2.0 cm lateral to the widest bony margin of the true pelvic side walls. The distal border was at the base of the obturator foramen or 1 cm below the anus, whichever was lower. The superior border was at the L5/S1 junction. The posterior field margin was a minimum of 1 cm behind the anterior bony sacral margin, and blocks were used to spare the posterior muscle and soft tissues. The external iliac nodes were not included in the lateral radiation fields. The anterior margin was at the most posterior aspect of the symphysis pubis. The anus was considered part of the target volume; therefore, it was included in the whole pelvic field. The whole pelvis plus the primary nodal groups at risk received 46.8 Gy. This was followed by a 3.6-Gy boost to the primary tumor bed.

Boost field. The intent of the boost was to treat the primary tumor with a 3-cm margin and not to include the nodal groups. Therefore, the exact size was determined by the size and location of the primary tumor. In general, field sizes measured 10 x 10 or 12 x 12 cm, and corner blocks were used if possible. Opposed lateral fields were used. The boost dose was 3.6 Gy; therefore, the total dose (pelvis + boost) was 50.4 Gy.