Resectable rectal cancers. Treatment by curative endocavitary irradiation.

Abstract

IT IS GENERALLY considered that rectal carcinoma is only slightly radiosensitive, and that radiation therapy has no place in its curative treatment. This opinion is not true in the case of early rectal cancers that can be treated by endocavitary irradiation . Rectal adenocarcinoma proves to be very radiosensitive with this method. The response of the tumor is favorable, even surprising; the chances of local control are good, as long as the indications are strictly respected. Endocavitary irradiation of rectal cancers consists of two techniques, contact x-ray therapy and interstitial curietherapy. Contact X-ray Therapy The characteristics of the machine used for contact x-ray therapy are a low voltage (50 kv), short focal distance (4 cm), high output (1,500 roentgen/min in air), a narrow tube (able to be introduced in a special rectoscope 3 cm in diameter) and substantial absorption of the radiation in the first 2 cm. The tube is very