RADIATION-THERAPY AS DEFINITIVE TREATMENT FOR SELECTED INVASIVE RECTAL-CANCER

Background. Eighty-four patients with invasive rectal adenocarcinoma w ere definitively treated with radiation during a period of 9 years in an attempt to achieve ''local control'' (eradication of rectal cancer and its associated morbidity) without radical resective surgery. Metho ds. Initially, endocavitary radiation alone was used in 13 patients wi th ''ideal'' carcinomas and in six patients with aggressive cancers. T o improve local control, 4500 cGy external radiation before the 6000 c Gy endocavitary radiation was used to treat 28 ideal lesions, 15 ''non ideal'' but potentially curable cancers, 14 aggressive cancers, and 8 patients with incurable metastatic disease. Results. Endocavitary radi ation alone resulted in local control for 8 of 13 patients with ideal carcinomas (62%); eventually 11 of 13 (85%) had control after three su ccessful salvage abdominoperineal resections. Local control was accomp lished in none of six patients with aggressive cancers. Use of externa l radiation before endocavitary radiation achieved local control in 93 % of patients with ideal lesions, eventually 100% after two salvage ab dominoperineal resections. Of the 15 nonideal but potentially curable lesions, 100% had eradication of local disease with the combined modal ities. Of the 14 with aggressive cancers and 8 with metastatic disease , 19 suffered failure of local control (86%). Eight of these had local salvage by surgical resection; the others died with local failure wit hin 6 months. Conclusions. External radiation, combined with endocavit ary radiation, is excellent, definitive treatment for selected, favora ble, invasive rectal cancers; however, there is little place for nonre sective management of aggressive rectal cancer, even for palliation, u nless life expectancy is less than 6 months.