Does a radiation dose-response relation exist concerning survival of patients who have soft-tissue sarcomas of the extremities? Radiation dose-response relation for soft-tissue sarcomas.

ABSTRACT

This study analyzes a single-institution experience by evaluating the impact on survival of increasing total dose of adjunctive irradiation in patients who had extremity soft-tissue sarcoma (ESTS). A retrospective review of the tumor registry at a university medical center from January 1984 through December 1992 yielded a total of 59 surgical patients of ESTS. With follow-up ranging from 30 to 135 months (median, 65 months), the 2-, 5-, and 8-year overall and disease-free survival for all patients was 86%, 71%, 58% and 76%, 70%, 56%, respectively. Multivariate analyses using the Cox proportional hazards model revealed that total radiation dose (p = 0.02), American Joint Committee on Cancer stage (p = 0.04), and tumor size (p = 0.006) were all significant prognostic factors of overall survival; however, only tumor size was predictive of disease-free survival (p = 0.02). When the effect of tumor size and disease stage were controlled in the Cox model, a dose-response curve between increasing total radiation dose and improved overall patient survival was indicated. This study demonstrates the significance of tumor size on predicting both overall and disease-free survival in patients who have soft-tissue sarcomas of the extremity. It also suggests, however, that a radiation dose-response relation may exist for overall survival. Future investigations should consider evaluating the minimal total radiation dose needed to optimize patient survival after limb-sparing surgery.