Histopathological studies on the effect of thermoradiotherapy for human malignant tumors

The histopathological study was performed on 16 human malignant tumors which were treated with thermoradiotherapy. The microscopic examination revealed marked necrosis throughout entire sections in 4 tumors to which irradiation to more than 60 Gy in combination with heating at over 42 deg C was delivered. In other 7 tumors, a massive coagulation necrosis occupied three fourths of tumor tissues, mainly in the part of the core. The remaining 5 tumors showed only slight histological changes, that is, the area of intratumor necrosis was less than three fourths of an entir tumor section. A marked destruction of blood vessels appeared in the tumor parenchyma in 13 of the 16 tumors, while in the stroma in only 2 tumors. A condensation of destroyed nuclei was revealed in 11 tumors. Viable tumor cells surviving after thermoradiotherapy were observed in the central area in 3 tumors, around blood vessels in 2 tumors and in the peripheral zone in 12 tumors. These results indicated that thermoradiotherapy affected the center area of tumors more prominently than the peripheral zone, and provided a rationale for the combined use of a high dose of radiation and hyperthermia in the definitive treatment of bulky tumors. (author)