[Multimodal therapy using hyperthermia for gastric cancer--with special reference to histological studies]

We carried out a combination preoperative therapy involving radiofrequency hyperthermia (8 MHz or 13.56 MHz) with radiation (10-MV X-ray) or chemotherapy (Mitomycin C, CDDP or UFT) for 24 advanced gastric cancers with the aim of preventing local recurrence and improving resectability. The tumor and histological effects were evaluated in each case. Furthermore, an agar phantom possessing a cavity, for simulating the stomach, was employed in an experiment to evaluate temperature distribution upon RF-heating. In the experiment using the agar phantom, the rising temperature around the cavity at 3 o'clock was higher than at 5' and 6 o'clock. This suggested that gastric juice and air must be aspirated when treating a patient by RF-heating. Of the 24 tumors, 4 (17%) showed partial response. Histological effects were observed in 67% of 21 primary tumors. The rate of histological effects in metastases of lymph nodes, liver and peritoneum were 29% (4/14), 100% (2/2) and 0% (0/4), respectively. Tumor response was closely correlated with irradiation and the temperature in the stomach cavity (over 42.5 degrees C). Almost all patients showed good tolerance of this combined therapy. These results show that combined treatment involving radiation, chemotherapy and hyperthermia appears to be a potentially useful from of preoperative therapy for patients with advanced gastric cancer.