Results of radiation therapy for unresected soft-tissue sarcomas

Definitive radiotherapy is uncommonly used in the management of soft-tissue sarcoma (STS). The purpose of the study was to evaluate the results of radiotherapy for unresected STSs treated in a single institution.

Between 1970 and 2001, 112 patients with STSs underwent radiotherapy for gross disease. Locations of the tumor were 43% in the extremities, 26% retroperitoneal, 24% in the head and neck, and 7% in the truncal wall. Histologic grades were 11% G1 and 89% G2 to G3. Median size of tumor at radiotherapy was 8 cm (range, 1-30 cm). Median radiation dose was 64 Gy (range, 25-87.5 Gy). Twenty percent of patients received chemotherapy. Local control (LC), disease-free survival (DFS), and overall survival (OS) rates were evaluated in univariate (log-rank) and then multivariate (Cox model) analysis to determine prognostic factors for STS.

Median follow-up for patients is 139 months (range, 30-365 months). The 5-year actuarial LC, DFS, and OS were 45%, 24%, and 35%, respectively. Tumor size at radiotherapy and radiation dose influenced LC, DFS, and OS in univariate analysis. LC at 5 years was 51%, 45%, and 9% for tumors less than 5 cm, 5 to 10 cm, and greater than 10 cm, respectively. Patients who received doses of less than 63 Gy had 5-year LC, DFS, and OS rates of 22%, 10%, and 14%, respectively, compared with 5-year LC, DFS, and OS rates of 60%, 36%, and 52%, respectively, for patients who received doses of 63 Gy or more. AJCC stage was related to the OS and DFS without statistically significant influence on LC. Use of chemotherapy, histologic grade, age, and location did not influence results. In multivariate analysis, LC was related to total dose (p = 0.02), T size at radiotherapy (p = 0.003), and AJCC stage (p = 0.04); DFS was related to total dose (p = 0.007), T size at radiotherapy (p = 0.01), and AJCC stage (p < 0.0001); and OS was related to AJCC stage (p = 0.0001) and total dose (p = 0.002), but not to T size, at radiotherapy. Major radiotherapy complications were noted in 14% of patients; 27% of patients who received doses of 68 Gy or more had these complications compared with 8% of patients treated with doses of less than 68 Gy.

Definitive radiotherapy for STS should be considered in clinical situations where no acceptable surgical option is available. Higher radiation doses yield superior tumor control and survival. A rise in complications occurs in patients who receive doses of 68 Gy or more, which provides a therapeutic window for benefit in these patients.