[Clinical results of thermoradiotherapy of locally advanced and recurrent breast cancers--comparison of results with radiotherapy alone].

From August 1979 through January 1988, 23 breast cancer patients with 25 tumors supposed to be refractory to conventional treatment were treated by thermoradiotherapy. Of the 25 tumors, 10 were locally advanced primary tumors [Group 1], 4 locally advanced recurrent tumors after operation more than 5 cm in maximum diameter [Group 2], and 11 locally recurrent tumors after radiotherapy [Group 3]. The present study was not a formal randomised-trial, but a historical-controlled study. The results were compared with tumors which were treated by radiation therapy alone between July 1962 and August 1979. The historical control groups comprised 11 tumors for Group 1, 17 for Group 2 and 19 for Group 3. Employing 4 types of heating devices (8, 13.56 MHz capacitive RF, 430, 2450 MHz microwave), hyperthermia was administered once or twice a week after irradiation, for 30-60 minutes per session, up to a total sessions of 2-9. Radiotherapy was delivered in fractions of 180 to 200 cGy per day, 5 days per week, up to 28-74.4 Gy in total, or in fraction of 400 cGy, two times per week, up to 28-60 Gy. Tumor temperatures were measured by inserting thermocouples into the tumors. The tumors that did not recur during follow-up of more than 3 months were regarded as locally controlled tumors, and the local control rate was calculated. The local control rate in Group 2 and the local response rate (CR + PRa) in Group 1 were higher than those of the historically controlled tumors. In Group 3, hyperthermia combined with lower total doses of irradiation showed a high local response rate similar to that by radiation therapy alone. Thus local hyperthermia in combination with radiation therapy seems to be more effective than radiotherapy alone for locally advanced and recurrent breast cancers.