Effects of local tumor hyperthermia on the growth of solid mouse tumors

The sensitivity to local tumor hyperthermia (43 degrees, 60 min) of a spectrum of eight different solid mouse tumors (Lewis lung carcinoma, M5076 ovarian carcinoma, colon carcinoma 38, colon carcinoma 26, mammary adenocarcinoma C3HBA, mammary adenocarcinoma 16C, glioma 26, and B16 melanoma) was investigated. A microwave (2.45-GHz) apparatus produced localized heating of the tumors without generation of whole-body hyperthermia. The temperature at the center of the heated tumors was regulated to within +/- 0.1 degrees while the temperature uniformity within the tumor was +/- 0.5 degrees. The local hyperthermia treatments reduced the size and retarded the growth of the treated tumors compared with control values for each of the tumors tested. The faster-growing Lewis lung carcinoma and B16 melanoma were the least responsive to treatment, while the slower-growing colon 38 and M5076 ovarian carcinomas were the most responsive. Multiple treatments resulted in longer grwoth delays and greater tumor growth inhibition than did single treatments. No consistent difference in life span between the control and treated groups was measured, and only five of 188 treated animals were cured.