This discussion will be limited to a consideration of radiation therapy of epidermoid carcinomas of the thoracic portion of the esophagus. Carcinomas of the upper third, as well as adenocarcinomas of the lower third, are excluded, as they present a different therapeutic problem, and everywhere in cancer therapy progress has been hastened by the recognition of the different types of tumors which may occur in a particular organ. Carcinomas of the upper third or cervical portion of the esophagus are biologically, therapeutically, and prognostically to be considered in the same group as hypopharyngeal carcinomas. While technical advancements may still improve their curability, we feel that the principles of treatment here are established. For these carcinomas 200-kv. radiation offers today an approximate mean curability of 20 per cent. While this figure may eventually be improved by better technic and the application of higher voltage, we do not believe that the latter per se offers a fundamentally new approach. The main reasons for the better results in tumors of the cervical, as compared with those in the thoracic esophagus, are probably their earlier recognition and their location, which permits the application of a sterilizing dose into the tumor with radiation of medium voltage. The exclusion of the glandular carcinomas of the lower third of the esophagus does not mean that these tumors are not responsive to irradiation. Some of the polypoid adenocarcinomas of the cardia are quite radiosensitive, and a number of cases treated by others (Merritt) and by ourselves have shown definite improvement under radiation therapy, as evidenced by the patient's general condition, temporary disappearance of the tumor as shown roentgenographically, and a change in the gastroscopic picture. These tumors are, however, biologically different from the epidermoid carcinomas and in the interests of clarity it seemed wiser to eliminate them. Treatment of carcinoma of the thoracic portion of the esophagus is still an unsolved problem. Although the number of apparent surgical cures has increased with the improvement of thoracic surgery during the last decade, the procedure is so formidable, and the prognosis in the individual case so unpredictable, that operation cannot be considered a solution. The local application of radium—intracavitary or interstitial—has universally failed; with the exception of Guisez, no one has reported any cures. This procedure has been discarded by more experienced observers because of the unsatisfactory results and the danger of acute perforation (Zuppinger). Two hundred-kilovolt roentgen therapy of these esophageal cancers is the only radiologic approach which, so far, has given sufficiently uniform palliative results to warrant its consideration as a clinical procedure with definite indications and contraindications.