PREOPERATIVE IRRADIATION FOR CANCER OF THE RECTUM WITH EXTRARECTAL FIXATION

Tumor mobility of rectal cancer is well known to have prognostic significance for operative resection, local recurrence, and survival. Between 1976-1988, 220 patients have been consecutively treated with high dose preoperative radiotherapy at Thomas Jefferson University Hospital. During this time period, 134 patients were clinically determined by the surgeon and radiotherapist to have extrarectal tumor fixation as a primary indication for preoperative irradiation and are the subject of this review. The patient population can be further divided into two subgroups which include 49 patients with clinical tethering/partial fixation, and 85 patients with completely fixed tumors. Patients were treated with 4-field pelvic radiotherapy to 45 Gy in 25 fractions. Depending on location and degree of fixation, a localized boost dose was frequently delivered to the tumor for an additional 4.8-9.6 Gy using opposed high-energy lateral fields. Surgical resection was instituted 4-6 weeks post completion of radiotherapy. Significant tumor regression permitted sphincter preserving surgery in 105/134 (78%) of these patients. With a median follow-up of 37 months, the overall 5-year actuarial survival for our postradiation Stage A/B1 patients was 92% (n = 28), and 63% for Stage B2/C patients (n = 91). Local recurrence occurred in only 7% of the Stage A/B1 patients, and 18% in the Stage B2/C patients. Analyzed by pre-treatment clinical evaluation, the 5-year actuarial survival of these patients was 68% and 60% in the clinically tethered and fixed tumor subgroups, respectively (p = .51). Pelvic control was demonstrated in 86% of the patients in the tethered subgroup, and in 80% of the preoperative fixed patients. The combined treatment was well tolerated, with complications limited to 6% of the patient population. We conclude that preoperative radiotherapy for rectal carcinomas with clinical extrarectal fixation provides optimal presurgical cytoreduction and excellent survival. Furthermore, sphincter function can be maintained in a majority of patients with appropriate attention to patient selection.