Megavoltage irradiation of epithelial tumors of the nasopharynx

The present analysis is limited to 251 patients treated with megavoltage irradiation at M. D. Anderson Hospital and Tumor Institute between 1954 and December 1977. The 5-year actuarial disease-free survival for all patients studied is 52%; it is 42%, 65%, and 14%, respectively, for those with squamous cell carcinoma, lympbepitbelioma, and unclassified carcinoma. There were 49 (19.5%) local failures, 32 (12.7%) regional failures, and 73 (29.19%) distant metastases. A previous review had shown an unsatiafactory control rate for T 1 and T 2 squamous cell carcinoma, the reason for which may have been that the actual delivered dose to the nasopbarynx was less thin the calculated dose. Since 1972, an additional 500 to 750 rad has been delivered through parallel opposed small fields centered over the angle of the nassopharynx. Thus, this analysis is divided into two periods, 1954 through December 1971, and January 1972 through December 1977, to evaluate the effectiveness of the treatment changes. The control rate for T 1 and T 2 squamous cell carcinomas has increased from 76.4% to 94.2%.