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.