PREDICTIVE FACTORS FOR SKIN REACTIONS IN PATIENTS TREATED WITH THERMORADIOTHERAPY

In this study we performed univariate analyses to analyse the predicti ve factors for skin reactions, i.e. erythema, thermal blisters and ulc eration, that occur during thermoradiotherapy. One hundred and twenty- six fields in 126 patients were treated with thermoradiotherapy using 915 MHz external microwave hyperthermia. Mean age of patients was 62 y ears. All but 11 lesions received previous therapy. Prior treatment in cluded surgery (75%), chemotherapy (60%) and/or radiation therapy (51% ). The mean previous radiation dose was 54 +/- 2 Gy. The concurrent tu mour radiation dose was 45 +/- 1 Gy, in 16 fractions, over 35 elapsed days (dose per fraction of 1.6-4.8 Gy). The mean number of heat sessio ns administered was 5.5 +/- 0.2 (range 1-14). In 83% of cases hyperthe rmia was administered biweekly. Forty-two patients were treated withou t any skin reaction (33%), erythema occurred in 59 fields (47%), trans ient thermal blisters occurred in 25 fields (20%) and ulceration occur red in 23 fields (18%). In 25 cases, two or more skin reactions (20%) were observed concurrently. Concurrent radiation dose correlated with skin reactions (p = 0.02). The incidence of skin reactions was inverse ly correlated with previous radiation therapy (p = 0.04) and previous radiation therapy dose (p = 0.04) possibly due to fibrosis. None of th e tumour or skin thermal parameters correlated with the reaction rate.