Résultats préliminaires de l’étude STIC PDR intitulée « Utilisation de la curiethérapie pulsée gynécologique (PDR) avec optimisation de la répartition de la dose et dosimétrie tridimensionnelle » pour les cancers du col utérin

Abstract

Purpose In 2005, a French multicentric-prospective study (“STIC PDR”) was initiated for patients treated for cervix carcinoma comparing brachytherapy method based on orthogonal X-rays (2D group) or based on 3D-imaging and PDR Brachytherapy (3D group). The study has ended after 2.5 years accrual and the enrollment of 801 patients. We will describe the first 637 patients. Patients and methods Two hundred and eighty-eight patients were included in the 2D group and 349 in the 3D group. Three subgroups of patients have been defined: brachytherapy–surgery (159 patients); external-beam radiotherapy (EBRT)–brachytherapy-surgery (264 patients); EBRT–brachytherapy (214 patients). Clinical data were comparable between 2D and 3D groups in each subgroup. In both groups, ICRU bladder and rectal points were drawned; in the 3D group, CTV volumes were delineated according to GYN-GEC-ESTRO recommendations (high-risk CTV and intermediate-risk CTV), as were the external wall of the OARs. The dose to 100 (D100) and 90% (D90) of CTV and the volume of CTV receiving 60 Gy (V60) were analysed. Results Brachytherapy: for each subgroup, results are comparable between 2D and 3D (isodose 60 Gy volume, dose to ICRU bladder and rectal points, TRAK). In the 3D group, CTV coverage was lower than GEC-ESTRO recommendations. Surgical data: the same proportion of patients were in complete-cervical pathologic remission between 2D and 3D groups (54 and 55%). There was no difference in coverage of CTVs between complete and partial remission in the 3D group. Conclusion The first results of the “STIC PDR” study show that physicians did not modify to a large extent their mode of prescription while evolving towards 3D brachytherapy. The follow-up of the patients will lead to precious data in the 3D group about the relationship between DVHs, late complications and local control.