Understanding the dynamics of tumours: How systems science can improve anti-cancer

Combined Hyperthermia-Radiotherapy (HT-RT) is an effective anti-cancer treatment and sometimes exhibits a surprisingly good clinical outcome. The combination of heat and radiation exhibits a synergistic effect when heating the tissue prior to or after irradiation up to approximately 42-43°C. The effect of moderate hyperthermia in combination with radiotherapy (HT-RT) was demonstrated in clinical trials and experimentally in vitro and in vivo. Several mechanisms which potentially contribute to the treatment response have been discussed. However, the full dynamics behind the synergistic effect of moderate heat (up to 43°C) and irradiation of the tumour remains unclear.

For improving and optimising the therapy, a deeper understanding of the dynamics behind the synergistic effect of heat and radiation is required. We propose a method for model-based data analysis using a bio-inspired dynamical model to explore experimental results in vitro. The method is based on a dynamic, radiobiological model (Multi-Hit Repair model), which is able to generate clonogenic survival - and Comet assay data in silico. These data can be compared to experimental data in vitro by using the Approximate Bayesian Computation (ABC) method. Interestingly, the model output is in agreement with all radiobiological observations investigated up to date, indicating that the model structure covers the essential aspects of the "real world" dynamics. The proposed method may serve as a good example to demonstrate how bio-inspired computer models can help to improve our understanding of the nature.