Temperature distribution in locally advanced breast carcinoma during hyperthermic treatment: relationship to perfusion, vascular density, and histology.

Temperature distributions achieved during hyperthermic treatment of 16 patients with locally advanced breast cancer were analyzed in relation to tissue perfusion, vascular density, and histology of treated volume. Temperatures were measured using multi-sensor thermistor probes inserted in the center and periphery of the treatment volume. A steady state temperature, Ts, and a perfusion related parameter, PERF, were determined for each probe location. Vascular density and tissue composition were determined by histologic analysis of biopsies taken from the temperature probe locations before treatment. Both malignant and normal tissue were found in the biopsies, reflecting a diffusive tumor growth pattern. The malignant and normal tissue compartments were analyzed separately using stereologic techniques. Ts, PERF, vascular density, and tissue composition differed significantly between patients. There was a clear relationship between Ts and PERF, showing that the local tissue perfusion was decisive for the temperatures achieved. Ts and PERF showed a clear correlation with the normal tissue vascular density, but not with the malignant tissue vascular density; that is, the treatment temperatures achieved were mainly determined by the vascularization of the normal tissue compartment. Fraction of necrosis was the only tissue compartment parameter that showed a clear relationship to Ts and PERF. Ts increased and PERF decreased with increasing necrotic fraction.