ESTRO 2025 - Abstract Book

S4011

Radiobiology - Tumour radiobiology

ESTRO 2025

3527

Digital Poster Development and validation of a radiobiological model incorporating tumour perfusion and oxygenation characteristics Kypros Demou 1 , Constantinos Zambolgou 2 , Triantafyllos Stylianopoulos 1 , Yiannis Roussakis 3 1 Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus. 2 Department of Radiation Oncology, German Oncology Center, Limassol, Cyprus. 3 Department of Medical Physics, German Oncology Center, Limassol, Cyprus Purpose/Objective: To report on the development and validation of a novel mathematical model simulating tumour growth and response to radiotherapy, uniquely incorporating tumour perfusion and oxygenation characteristics. Material/Methods: A continuous mathematical model was developed, building on a previous work [1], which simulates tumor growth and response to radiotherapy. The first part models tumour growth while integrating elastic and inelastic interactions within the tumour and the surrounding normal tissue. Tumour microenvironment modeling also includes changes in perfusion and oxygenation. The second part models the tumor’s response to radiotherapy. Cell death is calculated based on the Linear-Quadratic model, for each phase of the cell cycle individually, while dead cell removal rate is also modeled. Our model was validated against two pre-clinical murine studies and a clinical study [2] from the literature, which investigated tumour volume changes over time following radiotherapy, with different dose/fractionation schedules in prostate and head-and-neck cancer cases. Several additional clinical scenarios were also simulated, including examining conventional- hypo- and ultra-hypo- fractionated for prostate cancer cases, and examining the effect varying tumour oxygenation against fractionation or against intrinsic tumour radiosensitivity, to investigate its ability to realistically predict the clinically observed outcomes. Results: The model demonstrated good alignment with experimental data from pre-clinical (R 2 mean=0.84, range: 0.61-0.98,) and clinical (R 2 mean=0.85, range: 0.49-0.97) studies. Figure 1 shows the clinically acquired data of tumour volume from four head-and-neck patients receiving radiotherapy, along with the simulated volume changes using the developed model.

Figure 1: Fitting of the model to clinical data of head-and-neck cancer patients [2].