[Health Data Hub in France, use cases in oncology and radiation oncology]. / HealthDataHub ; plateforme des données de santé en France, application à l'oncologie radiothérapie.

Health data financed by the French national solidarity system constitute a common heritage. Such data should be exploited to optimize care while complying with ethics and fundamental rights of citizens. The creation of the Health Data Hub (HDH) was allowed by the 24 July 2019 Law on the organization and transformation of the French health system. Its objective is to enable authorized innovative project leaders to access non-nominative data via a state-of-the-art secure technological platform. It appears to be one of the strong points of the French Artificial Intelligence strategy. This structure is a public interest group which associates 56 stakeholders, mostly from the public authorities. It implements, in partnership with the National Health Insurance Fund, the major strategic orientations relating to the National Health Data System set by the French State and the Ministry of Solidarity and Health. The Health Data Hub allows cross-reference of consolidated databases with SNDS data. Several use cases are under construction. The creation of relational databases in radiation oncology is also possible through specific strategies to get pseudonymized data from the various radiotherapy software programs upstream of the Health Data Hub.

[Construction of radiobiological models as TCP (tumor control probability) and NTCP (normal tissue complication probability): from dose to clinical effects prediction]. / Construction des modèles radiobiologiques de type TCP (tumor control probability) et NTCP (normal tissue complication probability) : de la dose à la prédiction des effets cliniques.

In radiotherapy, the dose prescription is currently based on discretized dose-effects records that do not take into fully account for the complexity of the patient-dose-response relationship. Their predictive performance on both anti-tumour efficacy and toxicity can be optimized by integrating radiobiological models. It is with this in mind that the calculation models TCP (Tumor Control Probability) and NTCP (Normal Tissue Complication Probability) have been developed. Their construction involves several important steps that are necessary and important to understand. The first step is based on radiobiological models allowing to calculate according to more or less complexity the rate of surviving cells after irradiation. Two additional steps are required to convert the physical dose into an equivalent biological dose, in particular a 2Gy equivalent biological dose (EQD2): first to take into account the effect of the fractionation of the dose for both the target volume and the organs at risk; second to convert an heterogeneous dose to an organ into an homogeneous dose having the same effect (Niemierko generalized equivalent uniform dose (gEUD)). Finally, the process of predicting clinical effects based on radiobiological models transform doses into tumour control (TCP) or toxicity (NTCP) probabilities using parameters that reflect the radiobiological characteristics of the tissues in question. The use of these models in current practice is still limited, but since the radiotherapy softwares increasingly integrate them, it is important to know the principle and limits of application of these models.