Local-regional recurrences of breast cancer: Treatment with radiation therapy and local microwave hyperthermia

From October 1981 through September 1988, 31 local-regional recurrences of breast cancer in 26 patients were treated at the Oncology Center in Trento, Italy, with a combination of external radiation therapy (XRT) and superficial local microwave hyperthermia (Ht). The mean total XRT dose was 37.40 Gy, ranging from 19.80 to 60.00 Gy, depending on the extent of previous irradiation. Ht was delivered using the same superficial mw applicator, operating at frequencies between 280 and 480 MHz. The goal was to obtain a minimum intra- and peritumoral temperature of 42.5°C for 30 min. Ht was applied immediately after XRT, 2 or 3 times per week for a total of 1-9 sessions (median 2). Thirty lesions (97%) could be evaluated for response 3 months after the end of the combined treatment. Twenty (66.6%) complete responses, seven (23.3%) partial responses, and three (10%) with no change were observed. No significant acute local side effects were noted, with the exception of two thermal burns and one ulceration. Patients achieving complete response show actuarial long-term local control of 87.8% at 3 years. In our experience, Ht combined with a low/moderate XRT dose may be particularly valuable in the palliation of recurrences in previously irradiated regions. Excellent response rates can be obtained when Ht is combined with a radical dose of irradiation.