PURPOSE: To investigate the results of tongue cancer treatments retrospectively in order to compare the outcomes of radiotherapy and surgery among patients presenting with early-stage tongue cancer. METHODS: One-hundred and forty-three patients who underwent radical treatment of tongue cancer between 1976 and 1996 were classified into six treatment groups in order to compare the 5-year survival rate, 5-year local control and lymph node metastasis between the groups. Furthermore, prognostic factors were determined by univariate and multivariate analyses. RESULTS: The 5-year survival rate for the entire subject population was 71%, and that for patients diagnosed as having stage I, II, III and IV tumors was 85%, 80%, 76% and 53%, respectively. The 5-year survival rate of patients who underwent surgical treatment alone for early-stage tongue cancer was higher than that of patients who underwent interstitial radiotherapy alone (100% and 70%, respectively). The 5-year local control rate did not differ significantly between patients who underwent surgical treatment alone for early-stage cancer and those who underwent interstitial radiotherapy alone (87% and 86%, respectively). Furthermore, the survival rate did not differ significantly between patients presenting with cervical lymph node metastasis upon initial examination and those who developed cervical lymph node metastasis later (62% and 69%, respectively). The results of a univariate analysis showed that prognosis was significantly better for women and NO patients, and the results of a multivariate analysis confirmed that prognosis was significantly better for patients under 60 years of age, women, and NO patients. CONCLUSIONS: The survival rate of patients treated for early-stage tongue cancer was slightly higher for those who underwent surgical treatment alone compared with those who underwent interstitial radiotherapy alone. However, local control was comparable between these two groups of patients. © 2000, Japanese Society for Therapeutic Radiology and Oncology. All rights reserved.