Combined re-radiation therapy and regional or capacitive hyperthermia as a part of multimodal treatment for locoregional breast cancer recurrences in previously irradiated areas

Hyperthermia (HT) enhances the effects of radiotherapy (RT) and has shown benefit in recurrent breast cancer. Most existing studies focus on conventional superficial HT, whereas the efficacy of regional hyperthermia (RHT) and capacitive hyperthermia (CHT) in previously irradiated areas remains underexplored. Patients with locoregional breast cancer recurrences previously treated with RT were included in this retrospective analysis. Re-irradiation was delivered in combination with RHT or CHT and was integrated into an individualized multimodal treatment concept. HT was applied once or twice weekly immediate following RT, with temperature monitoring performed for RHT. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS) and toxicity. A total of 15 patients with 17 locoregional recurrences were included. Patients received re-RT with a median dose of 50 Gy and a median of 7 HT sessions (range, 1–24 sessions; Interquartile range (IQR), 5.5–10). After a median follow-up of 30.1 months (range, 5–76 months; IQR, 13–43) two patients experienced local progression during follow-up. The estimated 2-year PFS was 75%, and OS was 60% at last follow-up. Acute and late toxicities were limited to grade 1–2 events, with no grade ≥ 3 toxicity observed. This retrospective analysis demonstrates the feasibility of combining RHT or CHT with multimodal treatment in patients with recurrent breast cancer and provides encouraging preliminary clinical outcomes. Despite the limitations, these findings support the integration of RHT and CHT into salvage treatment strategies and justify further prospective investigation. Not applicable.