| Impact du schéma d’irradiation dans le cadre d’une irradiation stéréotaxique des carcinomes bronchiques non à petites cellules stade I : une étude rétrospective multicentrique (Impact of irradiation schedule in stage I non-small cell lung carcinoma SBRT: a multicenter retrospective study) Duvergé, Loïg - (2019-10-02) / Universite de Rennes 1 - Impact du schéma d’irradiation dans le cadre d’une irradiation stéréotaxique des carcinomes bronchiques non à petites cellules stade I : une étude rétrospective multicentrique
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Langue : Anglais Directeur(s) de thèse: Castelli, Joël Discipline : Oncologie Radiothérapie Classification : Médecine et santé Mots-clés : Radiothérapie stéréotaxique, cancer bronchique non à petites cellules, schéma d’irradiation, étalement, réoxygénation
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Résumé : Objectif : Déterminer l’impact en contrôle local et en survie globale d’un schéma d’irradiation continu versus discontinu (1 jour sur 2) en cas d’irradiation stéréotaxique d’un carcinome bronchique non à petites cellules stade I. Méthodes : 490 patients consécutifs traités dans 4 centres ont été rétrospectivement inclus et séparés en 2 groupes selon le schéma thérapeutique : continu (étalement (en jours) < 2 x nombre de fractions n) ou discontinu (étalement ≥ 2 x n). La survie globale, le contrôle local et la toxicité ont été comparés. Résultats : 245 patients ont été traités selon les 2 schéma continu et discontinu avec un suivi médian de 41 mois. Les deux groupes étaient comparables sur les facteurs confondants. Le contrôle local à 3 ans était de 92% (groupe discontinu) versus 84% (groupe continu p = 0,017). La survie globale à 3 ans était de 64% versus 52% (HR = 0,66 ; p = 0,024). La toxicité était équivalente. Conclusion : Le schéma d’irradiation discontinu améliore le contrôle local et la survie global. Abstract : Objectives: In the context of stereotactic body radiotherapy (SBRT) for early stage non-small cell lung cancer (NSCLC), the objectives of our study were to determine the impact on local control and overall survival of a continuous versus discontinuous schedule of radiotherapy. Materials and Methods: A total of 490 consecutive NSCLC stage I patients treated in 4 French radiation oncology centers between January 2008 and July 2018 were retrospectively analyzed. The dose delivered ranged from 30 to 75 Gy in 3 to 10 fractions (median BED10 = 125 Gy). Based on the ratio between the treatment duration (TD) and the number of fractions (n), patients were divided into two groups: continuous (TD <2n) versus discontinuous (TD ≥ 2n) schedule. Overall survival, local control and toxicity were compared using propensity score matching and Cox regression analyses. Results: The median follow-up was 41 months. The median age was 74 years old. Two hundred and forty-five patients were treated according to both the continuous regimen and the discontinuous regimen. The two groups were comparable in terms of the main confounding factors. The discontinuous schedule was correlated with better clinical outcome. The 3-year local control was 92% for the discontinuous treatment versus 84% for the continuous one (p = 0.0017). The 3-year overall survival was 64% for the discontinuous treatment versus 52% for the continuous one, Hazard Ratio of 0.66 (p = 0.0024). The irradiation schedule and the number of fractions were the only factors significant for the local control in multivariate analysis. The irradiation schedule, age, WHO performance status and T stage were significantly correlated with OS. Less than 2% of acute or post-treatment grade 3 pulmonary was reported for both groups. Conclusion: Our study is the first to show a positive impact of a discontinuous versus continuous SBRT schedule on overall survival as well as on local control for early stage NSCLC treated by SBRT, with similar low profile of toxicity. A multicenter randomized prospective study will be started in order to validate our results. | |||