Dogs with advanced and/or metastatic cancer were treated with thermal therapy in combination with a reduced dose of standard of care treatment. The evolution of clinical parameters indicated the safety of the treatment and the improvement in quality of life.

Thermal sensors in liver, rectum, and tumor confirmed a homogeneous heating of these body parts. The monitoring of clinical parameters showed acceptable and reversible changes in liver, cardiac, muscle and coagulation parameters, as expected. Combination of WBTT with both radiotherapy and chemotherapy only caused some low-grade adverse events.

Thermal therapy as adjuvant cancer therapy

WBTT seems to be promising as an adjuvant cancer therapy for several reasons.

• First, tumor cell-based experiments have confirmed a time- and temperature-dependent cytotoxic effect when temperatures between 41°C and 47°C were applied. The same cell-killing effect is generally assumed in in vivo situations. Moreover, several clinical studies underlined the importance of duration and extent of supranormal temperature achieved during thermal treatment.
• Second, WBTT mimics the physiological response of fever, and can be associated with the same therapeutic benefits: e.g. stimulation of the immune system, enhancing immune surveillance and contributing to long term protection from tumor growth and development of metastases.
• Third, WBTT has demonstrated to be a powerful adjuvant to chemotherapy and radiotherapy, by inducing changes in the oxidative metabolism, thereby sensitizing cancer cells to the cytotoxic effects of these treatment modalities.

In addition, the adjuvant effect of chemotherapy has been attributed to the ability of systemic thermal treatment to modulate the tumor microenvironment through increased blood flow and vessel permeability, decreased negative interstitial pressure, and modulation of the extracellular matrix architecture.