Interstitial thermoradiotherapy in the treatment of recurrent/residual malignant tumors.

From October 1981-November 1983, a total of 31 recurrent and/or persistent tumors in 29 patients were treated with interstitial radiotherapy in combination with interstitial hyperthermia. All patients had undergone extensive previous treatments by surgery and/or radiation therapy. In the present series, radiation used was administered by iridium 192 implant, with doses varying from 4000-6000 cGy, delivered at the rate of 1000 cGy +/- 10%/day. Hyperthermia was delivered by radiofrequency (8 lesions) and microwave (25 lesions) in two sessions, each raising tumor temperature to a minimum of 42 degrees C over 60 minutes. Of 26 lesions with at least one satisfactory heating session, there were 18 (69%) complete responses, five (19%) partial responses, and three with less than 50% regression. None of the five lesions with unsatisfactory heating resulted in complete response. Of the total group, two patients developed a cutaneous sinus and one patient developed a fistula. The detailed methodology and results are presented and recommendations for future improvements are discussed.