Optimisation de la radiothérapie guidée par l?image – TIGRE

Prostate cancer is the first cancer among men (1/8), representing about 50 000 new cases per year in France due to PSA screening. Despite a similar prevalence of latent prostate tumors around the world, incidence rates for clinical prostate cancer in Western men are 30-50 times higher than those for Asian men. However, data suggest that prostate cancer rates are increasing. Moreover in China, most patients subjected to prostate biopsy suffer from urinary symptoms and have elevated PSA levels. The lack of mass screening for prostate cancer results in a high rate of advanced tumors with nodal involvement and/or metastases. All prostate cancer can be treated by radiotherapy. Radiotherapy (RT) is the reference treatment of cancer, together with surgery and chemotherapy. RT can be proposed for instance to treat all localized prostate cancer, which represents the most frequent cancer among men (1/8). Three technical developments have dramatically increased the precision of radiation dose delivery: conformal radiotherapy (3DCRT) which has been developed during the last decade, Intensity Modulated RadioTherapy (IMRT) in the last years and Image Guided Radiotherapy (IGRT) developed more recently. Due mainly to the technical complexity of IGRT, its use is still limited. The goal of our project is to optimize IGRT in a routine practise in order to improve cancer curability, chosen prostate cancer as a model. Due to the recent apparition of the technique, the clinical experience is still very limited. Physicians and physicists are nowadays discovering the IGRT technique, trying to use it appropriately.The main objective of this project is to develop image processing / modeling tools and integrate them in a prototype to actually allow the practitioner to fully exploit the potential benefit of image guided radiotherapy in the treatment of prostate cancer, i.e. in a context of deformable organs. Thus, the two main expected results of TIGRE, focused on prostate cancer treatment, are (i) the development of a software prototype and its validation to provide the therapist with a reliable decision making aid tool taking actually into account the deformable nature of the organs (FRANCE), (ii) the proposition of a first original and operational approach for adaptive radiotherapy allowing the on-line re-planning of the treatment plan (CHINA). To reach this result the TIGRE project leaves a substantial place to the integration and evaluation steps.