Data on 116 patients with cancer of the base of the tongue treated in the years 1952 through 1962 have been reviewed. The male: female ratio was 3.8:1 and the 5 year survival rate was 27 per cent for males and 42 per cent for females. Although the figures suggest a preferentially better survival rate for females, no statistical significance could be attached to this finding because of the number involved. The patients were almost exclusively in the fifth, sixth, seventh, and eighth decades of life and the 5 year survival rates were remarkably similar for the various age groups.Presenting symptoms usually entailed some element of pain or unpleasant sensation directly attributable to the primary lesion, interference with deglutition or other basic functions of the tongue, or metastatic lymphadenopathy in the neck. No one presenting symptom seems to carry a more ominous prognostic significance than the others. Patients presenting with symptoms of short duration seemed to survive a little longer than did those with symptoms of longer duration, but again the differences were not statistically significant.Seventy-eight per cent of the patients had squamous cell carcinoma with a 5 year survival rate of 26 per cent, 11 per cent had lymphoma of varying types with a 5 year survival rate of 39 per cent and 11 per cent had miscellaneous, rare types of tumor. Patients with cancer apparently confined to the base of the tongue had a 5 year survival rate of 48 per cent, while regional dissemination naturally reduced the rate according to the extent of dissemination. Extension to the lateral hypopharyngeal wall apparently caused little reduction in 5 year survival rate, while dissemination in almost any other direction caused considerable reduction. Seventy per cent of the patients on admission had evidence of metastatic cervical lymphadenopathy and, of these, 24 per cent survived 5 years; when this was confined to the ipsilateral side of the neck, 28 per cent survived 5 years in contrast to 10 per cent of those with contralateral or bilateral metastatic lymphadenopathy. The cure rate decreased with the advancing stage of the disease, classified according to the T-N-M system: the 5 year survival rate was 56 per cent for patients with Stage I involvement, 50 per cent for Stage II, 28 per cent for Stage III, and 18 per cent for Stage IV. Of the 116 patients, 30 per cent survived more than 5 years.Broad treatment categories consisted of: (1) 68 patients given continuous conventional radiotherapy with a 5 year survival rate of 29 per cent; (2) 34 patients treated by split-dose methods with a 5 year survival rate of 32 per cent; and (3) 14 patients treated by miscellaneous methods such as cautery excision and implantation of radon seeds with or without supplemental radical lymph node dis section, with a 5 year survival rate of 29 per cent. No improvement in treatment effectiveness could be ascertained from either a change to supervoltage or cobalt 60 methods in 1954 or a change to splitdose methods in 1958. An apparent dosedependency, however, was noted: patients receiving suboptimal dose levels (below 5,000 r) had a 5 year survival rate of 19 per cent in contrast to 34 per cent with dose levels above this amount. An apparently increased incidence of second unrelated cancers appearing after treatment of the cancer of the base of the tongue was noted, 15 per cent of the series developing such additional neoplasms.Seven per cent of the series had fatal complications following radiotherapy; these included radiation myelitis, local fatal radionecrosis, and exsanguinating post-treatment hemorrhage.