Effectiveness of regional hyperthermia with chemotherapy for high-risk retroperitoneal and abdominal soft-tissue sarcoma after complete surgical resection: a subgroup analysis of a randomized phase-III multicenter study.

OBJECTIVE To determine whether regional hyperthermia (RHT) in addition to chemotherapy improves local tumor control after macroscopically complete resection of abdominal or retroperitoneal high-risk sarcomas. BACKGROUND Within the prospectively randomized EORTC 62961 phase-III trial, RHT and systemic chemotherapy significantly improved local progression-free survival (LPFS) and disease-free survival (DFS) in patients with abdominal and extremity sarcomas. That trial included macroscopically complete and R2 resections. METHODS A subgroup analysis of the EORTC trial was performed and long-term survival determined. From 341 patients, 149 (median age 52 years, 18-69) were identified with macroscopic complete resection (R0, R1) of abdominal and retroperitoneal soft-tissue sarcomas (median diameter 10 cm, G2 48.3%, G3 51.7%). Seventy-six patients were treated with EIA (etoposide, ifosfamide, doxorubicin)+RHT (≥5 cycles: 69.7%) versus 73 patients receiving EIA alone (≥5 cycles: 52.1%, P=0.027). LPFS and DFS as well as overall survival were determined. RESULTS RHT and systemic chemotherapy significantly improved LPFS (56% vs 45% after 5 years, P=0.044) and DFS (34% vs 27% after 5 years, P=0.040). Overall survival was not significantly improved in the RHT group (57% vs 55% after 5 years, P=0.82). Perioperative morbidity and mortality were not significantly different between groups. CONCLUSIONS In patients with macroscopically complete tumor resection, RHT in addition to chemotherapy resulted in significantly improved local tumor control and DFS without increasing surgical complications. Within a multimodal therapeutic concept for abdominal and retroperitoneal high-risk sarcomas, RHT is a treatment option beside radical surgery and should be further evaluated in future trials.