The role of adjuvant radiotherapy after marginal excision for local control of extremity and truncal soft tissue sarcoma

Abstract

9573 Background: Adjuvant radiotherapy (RT) has been shown to improve local control (LC) in patients with extremity and truncal soft tissue sarcoma (STS). The purpose of this study was to analyze how much RT promoted LC in patients with marginally excised STS compared with patients with widely excised STS. Methods: Two hundred and thirty-two patients with STS (173 extremity cases and 59 trunk cases) who had received conserving surgery were divided into 3 groups according to marginal status and the addition of RT; (1) wide excision alone (n = 56, Group A), (2) wide excision plus RT (n = 64, Group B) and (3) marginal excision plus RT (n = 112, Group C). LC, overall survival, and morbidity rates were retrospectively compared among 3 groups. Results: There were no differences in age, gender, pathologic type, and tumor site among three groups, but Group A had the higher incidence of small-sized tumor and low grade tumor than other groups. Thirty-eight patients experienced local failures (LF) after completion of treatment. Group C had similar incidence of LF compared with Group B (Group A; 4%, Group B; 21%, and Group C; 19%). Overall 5-year and 10-year LC rates were 80% and 70%, and there were no significant differences between Group B and Group C in 10-year LC rate (Group A; 84%, Group B; 65%, and Group C; 68%). Tumor grade and tumor site were found to be significant predictors of LF. Group C had lower 10-year overall actuarial survival rate compared with Group B (Group A; 85%, Group B; 78%, and Group C; 69%). This was associated with significantly different incidence of distant failure (Group A; 11%, Group B; 16%, and Group C; 29%, p=0.008). Seven patients suffered from wound dehiscence, and 1 patient from bone necrosis. The incidence of Grade 3–4 late complication was higher in Group B than Group A and Group C (Group A; 0%, Group B; 9.3%, and Group C; 1.7%, p=0.03). Conclusions: Our data indicate that RT seems to promote LC in patients with positive or close margin up to that of patients with wide margin in extremity and truncal STS. We suggest that conserving surgery and RT for patients with marginal STS should be the alternative choice rather than aggressive surgery for better LC without deteriorating limb-function or causing serious complication. No significant financial relationships to disclose.