Five-year results from a Scandinavian sarcoma group study (SSG XIII) of adjuvant chemotherapy combined with accelerated radiotherapy in high-risk soft tissue sarcoma of extremities and trunk wall

Abstract

Purpose: To evaluate adjuvant chemotherapy and interpolated accelerated radiotherapy (RT) for adult patients with high-risk soft tissue sarcoma in the extremities or trunk wall.

Methods and materials: High-risk soft tissue sarcoma was defined as high-grade malignancy and at least two of the following criteria: size≥8 cm, vascular invasion, or necrosis. Six cycles of doxorubicin and ifosfamide were prescribed for all patients. RT to a total dose of 36 Gy (1.8 Gy twice daily) was inserted between two chemotherapy cycles after marginal margin resection regardless of tumor depth or after wide-margin resection for deep-seated tumors. RT was boosted to 45 Gy in a split-course design in the case of intralesional margin resection.

Results: A total of 119 patients were eligible, with a median follow-up of 5 years. The 5-year estimate of the local recurrence, metastasis-free survival, and overall survival rate was 12%, 59%, and 68%, respectively. The group receiving RT to 36 Gy had a local recurrence rate of 10%. In contrast, the local recurrence rate was 29% in the group treated with RT to 45 Gy. The presence of vascular invasion and low chemotherapy dose intensity had a negative effect on metastasis-free and overall survival. Toxicity was moderate after both the chemotherapy and the RT.

Conclusions: Accelerated RT interposed between chemotherapy cycles in a selected population of patients with high-risk soft tissue sarcoma resulted in good local and distant disease control, with acceptable treatment-related morbidity. The greater radiation dose administered after intralesional surgery was not sufficient to compensate for the poorer surgical margin. Vascular invasion was the most important prognostic factor for metastasis-free and overall survival.