EFFETTI ANTIPROLIFERATIVI DELLA TERMOTERAPIA: UNO STUDIO DI ONCOLOGIA SPERIMENTALE

Thermotherapy is supposed to induce irreversible cell damage in tumour cells. Aim of this study was to evaluate the antiproliferative activity of temperatures between 45 and 65°C on various cancer cell lines and to compare the biological effects of water-bath and microwave induced thermotherapy, on cell proliferation. Cell cultures from five different tumours (DU-145, PC3, RTEJ, K562, Daudi) were placed in a precision water-bath and maintained for 1 hour at temperatures ranging between 37 and 65°C (experiment 1). Cell cultures from DU-145 and PC3 tumours were exposed for 1 hour at 50.4°C either in a precision water-bath or in a microwave field (>1 GHz frequency) (experiment 2). The antiproliferative effect of thermotherapy was evaluated, in both experiments, by 3H-thymidine uptake. Experiment 1: water-bath induced thermotherapy caused significant inhibition of cell proliferation with great variability among the different cell lines: 15.5-84.1% inhibition at 45°C, 19.1-89.4% at 50°C, 50.2-93.9% at 55°C, 77.5-97.5% at 60°C, 70.7-99.6% at 65°C. Experiment 2: one-hour thermotherapy treatment at 50.4°C induced 54.1% (microwaves) and 41.3% (water-bath) inhibition rates in PC3 cell line; 81.1% (microwaves) and 76.5% (water-bath) inhibition rates were observed in DU-145 cell line. In conclusion, a significant, although small, percentage of tumour cells survived 1 hour exposure to temperatures between 45 and 65°C. Antiproliferative effect of microwave thermotherapy seems to be related to thermal effects of the electromagnetic radiation.