Thirty-two cases of esophageal cancer were treated with thermochemotherapy from August 1984 to June 1985. A combination of bleomycin (20 mg per session iv) and cisplatin (0.5-0.9 mg/kg per session as low dose and 1.0-2.0 mg/kg per session as high dose), or of bleomycin, cisplatin (high dose), and cyclophosphamide (400-600 mg per session) were the treatment regimens. A 915-MHz microwave applicator was inserted into the lumen of the esophagus for heating. The temperature at normal adjacent tissue to the cancer was at 43-44 degrees C, while the temperature of the cancer was at 45 degrees C-50 degrees C. Chemotherapy and hyperthermia were administered simultaneously, once a week for six to eight sessions. The response rate in the low-dose group was 36.4% (four of 11) and 81% (17 of 21) in the high-dose group. The complete response rate in the low-dose group was zero of 11 patients, with 38.1% (eight of 21) in the latter group. The relationship between power output and tumor response is also discussed.