Preoperative Radiotherapy in Patients with Lower Rectal Cancer: Results of Sphincter-Preservation, Treatment Outcome and Morbidities

Abstract

Purpose: To study the impact of preoperative irradiation on enhancing sphincter preservation and to evaluate the treatment outcome in patients with lower rectal cancer. The results were analyzed for the endpoints of sphincter preservation, sphincter function, pelvic control, disease-free survival, overall survival and treatment-related morbidities. Materials and Methods: From 1992 to 1996, 43 patients with clinically resectable rectal cancer received preoperative radiotherapy at our department. All of these patients had undergone a prospective clinical assessment by their surgeons and were declared to require an abdominoperineal resection due to the proximity of the tumor to the anal sphincter. The whole pelvis received 37.5 Gy in daily fraction of 2.5 Gy with parallel opposed anterior-posterior portals. Results: Thirty of the forty-three patients (70%) were able to undergo low anterior resection. The majority (88%) of patients had good sphincter function after sphincter-preserving surgery. The pathologic stage was T2 in 11 patients and T3 in 32 patients. The 3- year overall survival rate, disease-tree survival rate, and local control rate of the 43 patients were 60%, 62%, and 89%, respectively. In univariate analysis, pathologic stage and the presence of regional lymphadenopathy were noted as significant prognostic factors for both overall survival and disease-free survival. With regard to local control, only the presence of regional lymphadenopathy showed prognostic significance for local control. No difference in survival rate and local control rate was observed between patients undergoing low anterior resection and those undergoing abdominoperineal resection. In multivariate analysis, pathologic stage was noted as the only independent prognostic factor for disease-free survival; likewise, only the presence of lymphadenopathy was demonstrated as an independent predictor for local control. No clinical and pathologic parameters were proved to be independent prognostic factors for overall survival. Acute intestinal toxicity included grade 1 in 10 (23%) patients, grade 2 in 18 (42%) patients, and grade 3 in 2 patients (5%). No patients had acute urological toxicity. Conclusion: With the help of preoperative radiotherapy, a significant proportion of patients would have a chance to receive sphincter-preserving surgery. Furthermore, the preserved sphincter functioned well in most of the patients. Further efforts should be made to reduce the treatment-related morbidities.