PubMedDate not supplied
Seventeen patients with locally advanced breast cancer were given hyperthermic treatment, and changes in temperatures and thermal doses with fraction number were studied. The changes were related to the vascular density of the treated volume before treatment. Multi-point thermistor probes were used for temperature measurements. Two parameters were determined for each probe location, a steady-state temperature, Ts, and a thermal dose, t43. To quantify changes in Ts and t43, linear curves were fitted to plots of these temperature parameters versus fraction number. The slopes of the curves, kTs and kt43, were used to represent the changes in Ts and t43, respectively. Vascular density was determined by histological analysis of biopsies taken from the temperature probe locations before the first heat treatment. Generally, Ts and t43 increased with increasing fraction number. kTs and kt43 were positively correlated to the vascular density of the normal tissue in the treatment volume, i.e. the increase in Ts and t43 was largest in the best-vascularized tissue. The cooling capacity of the normal tissue was probably reduced during the later heat fractions, either because of direct damage to the blood vessels or because of an impaired thermoregulative response. No relationship was found between the temperature parameters and the vascularization of the malignant tissue in the treatment volume. The present results show that the use of a fractionated schedule for heat treatment of locally advanced breast carcinoma may increase the temperatures and thermal doses achieved during treatment. A more uniform heating of the tumours can therefore be achieved by giving multiple heat fractions in the tumour areas that are difficult to heat adequately in one session.