Soft tissue sarcomas treated with postoperative external beam radiotherapy with and without low-dose-rate brachytherapy.

Purpose: Patients treated for soft tissue sarcoma with adjuvant low-dose-rate brachytherapy (BT) plus external beam radiotherapy (EBRT) were compared with those treated with adjuvant EBRT alone. The hypothesis was that higher doses from postoperative BT plus EBRT would improve local tumor control.

Methods And Materials: The medical records of 130 sarcoma patients definitively treated between February 1983 and February 2001 were reviewed. Of these, 25 patients received BT followed by EBRT, and 61 were treated with EBRT alone. Overall survival, freedom from distant metastasis, and local control were calculated using Kaplan-Meier estimates. Univariate and multivariate analyses were performed. The mean postoperative radiation dose with EBRT alone was 59 Gy (range, 50-74) and 50 Gy (range, 40-70 Gy) when low-dose-rate BT was included. The mean implant dose was 16 Gy (range, 10-20 Gy).

Results: The 5-year Kaplan-Meier estimate for overall survival for BT plus EBRT and EBRT alone was 82% and 72% (p = 0.93), respectively. The 5-year freedom from distant metastasis and freedom from local failure rate for BT plus EBRT vs. EBRT alone was 90% vs. 78% (p = 0.15) and 90% vs. 83% (p = 0.25), respectively. In the univariate subset analysis, Stage III patients had better local control at 5 years (100% vs. 62%, p = 0.03) and a trend was noted for better local control for high-grade tumors (100% vs. 74%, p = 0.09) if treated with BT plus EBRT. No statistically significant predictors were found on multivariate analysis for local control. The median follow-up was 62 months.

Conclusion: Local control at 5 years was high in both groups at 83% and 90%. On univariate analysis, Stage III patients had improved 5-year local control and a trend was found toward better local control for high-grade tumors. On multivariate analysis, no predictors were found for better local control; however, the numbers of Stage III and high-grade patients were small, which may have masked a possible benefit of BT plus EBRT in this population.