ESTRO 2025 - Abstract Book

S1670

Clinical - Sarcoma & skin cancer & malignant melanoma

ESTRO 2025

Purpose/Objective: To assess the outcomes of high-grade soft tissue sarcomas (STS) of the extremities treated with neoadjuvant radio(chemo)therapy in a single-institution series. Material/Methods: This study involved 102 patients (median age 52 years, range: 16-86) with localized, high-grade STS of the extremities. All cases underwent a multidisciplinary review involving radiation oncologists, orthopaedic surgeons, medical oncologists, radiologists, and pathologists. Preoperative radiotherapy with a median dose of 50 Gy delivered in 25 fractions (range 18-50) was given to all patients. Sixty-eight patients received preoperative chemotherapy, with seven continuing postoperatively. Conservative surgery followed a median of 5 weeks (range 2 14) post-radiotherapy. Results: Over a median follow-up of 65 months (range 2-207), 40 patients (39.22%) experienced relapse: 2 (1.96%) locally, 36 (35.29%) with distant metastases (median onset 17.08 months, range 2.86-147.25), and 2 (1.96%) with both. The 5 year actuarial rates were: local control (LC) 96.90%, metastasis-free survival (MFS) 70.00%, disease-free survival (DFS) 69.00%, and overall survival (OS) 96.60%. Surgical margins were wide in 74.76% of patients, marginal in 19, and intralesional in 7. Histologic evaluation showed a median tumor necrosis of 80% (range <10%-100%). Log-rank tests indicated statistically significant better 5-year DMFS and DFS in patients with spindle cell histology (p=0.016, p=0.012) and lower median dose (p=0.047, p=0.021), better 5-year LC with wide resection margins (p=0.004), and improved 5-year OS with chemotherapy (p=0.008) (Table 1). None of the significant differences recorded in the multivariate analysis were confirmed in the multivariate analysis (Cox's proportional hazard method).

Table 1 : actuarial results and univariate analysis.

Conclusion: Neoadjuvant radiotherapy, combined with conservative radical surgery, achieves excellent LC and OS. This underscores the importance of thorough, multidisciplinary evaluation. The extended follow-up period is crucial for timely detection of metastases, which can occur long after treatment.

Keywords: neoadjuvant radiotherapy, sarcomas