Primary Radiation Therapy of Malignant Salivary gland Tumors by Conventional Megavoltage Irradiation: Korea Cancer Center Hospital / 대한치료방사선과학회지

ABSTRACT

Retrospective analysis of survival rates was undertaken in the patients of 58 cases treated with conventional radiation therapy for malignant salivary gland tumors between January 1975 and December 1984 in Korea Cancer Center Hospital (KCCH). They were patients whose long-term follow-up was possible and who had refused surgery or had had recurrences postoperatively. Out of 58 patients, 25 patients (43.1%) had mucoepidermoid carcinomas and 24 patients (41.3%) adenoid cystic carcinoma. Total actuarial survival rates at 5 years and 10 years were 68.2% and 31.8% respectively, but disease-free survival rates, 43.2% and 13.0%, respectively. According to TNM stage, the survival rates at 5 years were 86.5% in T1, 40.0% in T2 + T3, and 0% in T4. In terms of histologic types, 5 years disease-free survival rate of adenoid cystic carcinomas (40.1%) was lower than that of mucoepidermoid carcinomas (49.8%) but overall survival rate (77.3%) was much higher than that of mucoepidermoid carcinomas (51.5%). Therefore, we concluded that the patients, who had had disease after failure of treatment, could survive during a certain period of time and their alive times were 2 years on the average. There was a difference in survival rates in the mucoepidermoid carcinomas in terms of histological grade of differentiation and it was a arbiter in prognosis 5 YSR of low-grade was 78.8% and higher 2 times than that of high-grade. There was no difference in survival rates according to location and sex. The number of patients having minor salivary gland tumors was 6 cases and their actuarial 5 YSR was 32.3%. Consequently, prognostic factors which influence the survival rates of patients with malignant salivary gland tumors are thought to be 1) histological ubtypes 2) T and N staging (AJCC) 3) histological grade, especially in mucoepidermoids.