Long-term results of thermoradiotherapy for superficial, subsurface tumors using a 430 MHz microwave heating system.

Superficial, subsurface tumors of 93 patients were treated with thermoradiotherapy using a 430 MHz microwave heating system (HTS-100). All patients had malignant tumors, and all were treated with a combination of hyperthermia and radiation. Satisfactory temperature data for each thermal parameter were achieved within a 5 cm depth for each tumor. The overall complete response (CR) rate was 39.8%; in the less than or equal to 3 cm (depth of tumor), the CR rate was 66.7%, in the 3-5 cm group, the CR rate was 42.9%. In the multivariate analysis, duration of local control correlated with tumor responses (CR). There were no instances of prominent late complications that were observed for greater than or equal to 6 months. This study suggests that the HTS-100 may improve tumor response and the duration of local control of superficial and subsurface tumors.