Definitive radiation therapy for selected cancers of the rectum.

During the last 15 years, over 400 patients with adenocarcinoma of the rectum have undergone a course of endocavitary irradiation for cure or palliation of Dukes' A and B disease. This treatment method makes use of an unconventional fractionation scheme, by which the tumour receives 10,000-12,000 cGy in approximately four fractions over a period of about 60 days. The treatments are separated by an interval of 2 or 3 weeks. This method of definitive irradiation allows suitable patients to avoid abdominoperineal resection and its drawbacks. Hospitalization is avoided and the patients maintain a normal daily life. Approximately 15-20 per cent of all rectal cancer patients may be expected to fulfil the criteria for selection, which are sufficiently strict that the local control (95 per cent) and 5-year survival rates (94 per cent) can exceed those of surgery for comparable disease.