Comparison of the secondary cancer risk after conventional and intensity-modulated radiotherapy using an animal model

• Applicants: Dr. Jens Fleckenstein; Professor Dr. Frank Giordano; Professor Dr. Gerhard Glatting; Professor Dr. Frederik Wenz
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology
• Term: from 2014 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 256898620

External-beam radiotherapy is an integral part of current multimodal cancer therapies. Over the past decades, radiation-induced adverse effects were consequently reduced by improving target coverage with higher conformality, which was enabled by the advent of intensity-modulated Radiotherapy (IMRT). However, to achieve a high degree of conformality, the technique exposes a significant volume of the body with low radiation doses, which is often referred to as 'low-dose bath'. It has been hypothesized that IMRT may therefore increase secondary cancers, which is controversially discussed as there are to date no to little experimental (standardized) data on the incidence of secondary cancers in low-dose areas. Our group has commissioned a Micro-CT as small-animal irradiation device and, as a first step of this proposal, we now aim to establish a Monte-Carlo-based planning system to enable small animal IMRT. We will then define a fixed target volume in tumor-permissive rats, which will be irradiated either conventionally (via opposing fields) or via rotations in an intensity-modulated fashion. The primary objective is comparing induced tumor incidences in high-, low- and no-dose areas. A secondary goal is to establish overall and cancer-free survival rates. The project displays the first standardized comparative assessment of cancer incidences after conventional and modulated radiotherapy and will provide data for a re-assessment of risks associated with the technique.

• DFG Programme: Research Grants