Hyperthermia (HT) is a treatment which obtains the anti-tumor effect by heating at 42.5°C or above. In addition, it is assumed that the effect of anti-cancer medicine is improved by combined with chemotherapy. However, it has been reported that mild-hyperthermia (MHT), under the 42.5°C treatment, makes immunity activate for tumor growth inhibition and MHT can enhance the anti-tumor effect even with chemotherapy treatment. Here, we demonstrate verification and the fundamental mechanism of the anti-tumor effect jointly, using it with MHT and chemotherapy. Moreover, we investigated the blood flow inside the tumor due to heat processing and the quantity of chemotherapeutic drug.
C3H/He mice (male, 8 weeks) were used. 1 × 10⁶ squamous cell carcinoma (SCC-VII) cells were transplanted in the right femoral region of mice and subjected to experiment when the tumor had grown to 7 mm in diameter. For the observation of tumor growth, we divided 6 groups : non processing group, MHT group (Processing temperature : 41.0°C), HT group (Processing temperature : 43.0°C), cis-diamminedichloroplatinum (II) (CDDP) dosage group, MHT combined with CDDP group (CDDP + MHT) and HT combined with CDDP group (CDDP + HT). Further, the tumors were extracted after all experiments were complete and then stained as the pathological specimen of the tumors.
CDDP + MHT group inhibited tumor growth 1.3 times in comparison with the CDDP group and enlarged necrosis range in the tumor by pathology. Also we observed increase of blood flow by MHT and the quantity of CDDP treating with MHT in the tumor. These results suggest that MHT treatment causes anti-tumor effect by enhancing blood flow and chemodrug uptake in the tumor.