Radiation therapy of the nasopharyngeal cancer and its prognostic factors.

Abstract

39 patients with the regional nasopharyngeal cancer (NPC) underwent radiation therapy from 1975 through 1984 in the Department of Radiology, Chiba University Hospital. A retrospective study was carried out to find out prognostic factors of these NPC patients. Radiation therapy was performed under megavoltage condition. 31 patients were given more than 50 Gy. 41% of the whole had T4 extension and 69% had lymph node metastasis. The pathological slides were reviewed and classified by the proposal of Shanmugaratnam. Advanced N-stage and the absence of the lymphocytic infiltration tended to affect the survival unfavorably, whereas the prognostic significance of histology, especially of keratinizing squamous cell carcinoma remained unclear. T4 lesion often recurred even with high dose radiation therapy. To improve the local control rate in NPC, wide field irradiation from the base of skull to the lower neck seemed necessary as well as the dosage greater than 66 Gy.