Long-term outcome of patients treated by radiation therapy alone for salivary gland carcinomas.

Abstract

To review a single-institution experience with the management of salivary gland cancers treated by radiation alone. Between 1960 and 2004, 45 patients with newly diagnosed salivary gland carcinomas were treated with definitive radiation to a median dose of 66 Gy (range, 57-74 Gy). Distribution of T-stage was: 24% T1, 18% T2, 31% T3, and 27% T4. Histology was: 14 mucoepidermoid (31%), 10 adenocarcinoma (22%), 8 adenoid cystic (18%), 4 undifferentiated (9%), 4 acinic (9%), 2 malignant mixed (4%), 2 squamous (4%), and 1 salivary duct carcinoma (2%). No patient had clinical or pathologic evidence of lymph node disease. Median follow-up was 101 months (range, 3-285 months). The 5-year and 10-year rate estimates of local control were 70% and 57%, respectively. A Cox proportional hazard model identified T3-4 disease (p = 0.004) and radiation dose lower than 66 Gy (p = 0.001) as independent predictors of local recurrence. The 10-year overall survival and distant metastasis-free rates were 46% and 67%, respectively. Radiation therapy alone is a reasonable alternative to surgery in the definitive management of salivary gland cancers and results in long-term survival in a significant proportion of patients. Radiation dose in excess of 66 Gy is recommended.