The use of irradiation therapy in the treatment of tumors of the rectum and rectosigmoid.

As a means of increasing local control and disease-free survival in patients with carcinoma of the rectum and rectosigmoid, preoperative and postoperative irradiation therapy have been shown to be effective. The question of the sequence of delivering adjuvant radiation therapy is not settled; however, the benefits and deficits of irradiation therapy as an adjuvant to surgery preoperative or post-operative are reviewed. Basic principles of radiation oncology affecting the selection of the sequence and technique of treatment are discussed.