Mise en place de l'imagerie embarquée au Centre Jean Perrin

L'installation dans le département de radiothérapie du Centre Jean Perrin de 2 nouveaux accélérateurs équipés d'imagerie embarquée (tomographie conique Cone Beam CT kV) a motivé une évaluation de l'outil et une modification des pratiques de contrôle de positionnement au poste de traitement. La mise en pratique du contrôle du positionement du patient par 2 clichés orthogonaux les 3 premiers jours puis de façon hebdomadaire, a été étendue à tous les postes de traitements, avec une systématisation de la conduite à tenir en cas de modification par rapport aux marges attendues. La mise en œuvre de ces contrôles mobilise 3h de temps médical par jour et une partie de cette étude a consisté à évaluer la possibilité de réaliser une délégation partielle de ces contrôles. Dans 96,7% des cas l'écart des mesures est <=3mm ce qui permettrait de déléguer ce contrôle aux MER. Une deuxième partie de ce travail a été l'analyse du Cone Beam CT en ORL et sur la prostate. En ORL, l'analyse confirme qu'il existe des mouvements de la tête dans le masque et que ces derniers s'accentuent à la 4ème semaine au moment de la perte de poids du patient. En fin d'irradiation il existe une diminution du volume des parotides, associée à une augmentation de la dose reçue aux parotides et à la moelle. Les doses reçues par le rectum lors d'une irradiation prostatique sont supérieures à la dosimétrie prévisionnelle et peuvent être corrigées par un recalage osseux optimal. Les fiduciaires ou le CBCT devraient permettre de réduire la dose au rectum surtout en cas d'escalade de dose. L'utilisation en pratique de routine du Cone beam CT n'est pas encore utilisable car il demande du temps médecin et machine supplémentaire.CLERMONT FD-BCIU-Santé (631132104) / SudocSudocFranceF

Delineation of the Prostate Bed: The “Invisible Target” Is Still an Issue?

For pathological high-risk prostate cancer, adjuvant irradiation has shown a survival benefit. Phase III studies have highlighted that half men would face biochemical relapse and would be candidate for radiotherapy at adjuvant or salvage times. Despite at least four published international contouring guidelines from different collaborative groups, discrepancies remain for volumes, delineation, and margins to be considered in order to optimize radiotherapy planning. This article from “Groupe d’Etude des Tumeurs UroGénitales (GETUG)” members will focus on controversies to help clinicians to create best volume delineation for adjuvant or salvage post prostatectomy radiotherapy

Intraprostatic Fiducials Compared with Bony Anatomy and Skin Marks for Image-Guided Radiation Therapy of Prostate Cancer

International audiencePurpose Prostate motion occurs during radiotherapy for localized prostate cancer. We evaluated the input of intraprostatic fiducials for image-guided radiation therapy and compared it with bony anatomy and skin marks. Methods Eleven patients were implanted with three fiducial markers in the prostate. Daily sets of orthogonal kV-kV images were compared with digitally reconstructed radiography. Data were recorded for skin marks, bony anatomy, and fiducial markers. The variations were analyzed along three principal axes (left-right: LR, superoinferior: SI, and anteroposterior: AP). Results A total of 2,417 measures were recorded over 38 fractions of radiotherapy (76 Gy). Fiducial marker movements from bony anatomy were ≤ 5 mm for 84.2% (confidence interval: CI 95%±1.5), 91.3% (CI 95%±1.1), and 99.5% (CI 95%±0.4) of the measures along the AP, SI, and LR axes, respectively. Ninety-five percent of the shifts between a fiducial marker and the bony anatomy were < 8 mm in the AP and SI axes, and < 3 mm in the LR axis. Fiducial marker movements from skin marks were ≤ 5 mm for 64.8% (CI 95%±1.9), 79.2% (CI 95%±1.6), and 87.2% (CI 95%±1.3) of the measures along the AP, SI, and LR axes, respectively. Bony anatomy movements from skin marks were ≤ 5 mm for 84% (CI 95%±1.4), 92% (CI 95%±1.1), and 87% (CI 95%±1.3) of the measurements along the AP, SI, and LR axes, respectively. Conclusion Using fiducial markers provides better accuracy of repositioning of the prostate than using bony anatomy and skin marks for image-guided radiotherapy of prostate cancer

Early toxicity of a phase II trial of combined salvage radiotherapy and hormone therapy in oligometastatic pelvic node relapses of prostate cancer (OLIGOPELVIS GETUG P07)

International audiencePURPOSE:Limited pelvic nodal relapse of prostatic cancer is a paramount challenge for locoregional salvage treatments. Salvage whole pelvis radiotherapy as considered in the BLINDED trial, is an attractive option but with concerns about its toxicity. This article describes early toxicity with the technique.METHODS AND MATERIALS:BLINDED was a prospective multi-center phase II trial investigating high-dose salvage pelvic irradiation with an additional dose to the fluorocholine-based positron-emission-tomography (FCH-PET)-positive pelvic lymph nodes (PLN), combined with six-month androgen blockade. The prescribed dose was 54 Gy in 1.8 Gy fractions with up to 66 Gy in 2.2 Gy fractions to the pathological PLN. Early toxicity was defined until one year after radiotherapy. Patients quality of life was assessed using the EORTC questionnaires (QLQ-C30 and QLQ-PR25).RESULTS:Seventy-four patients were recruited in fifteen French radiation oncology departments between August 2014 and July 2016. Seven were excluded before treatment because of violation of the inclusion criteria. The intention-to-treat analysis therefore included sixty-seven patients. Half of them had received prior prostatic irradiation. Median age was 67.7 ± 6.5 years. Grade 2 acute urinary toxicity was observed in 9/67 patients (13.4%) and grade 2 one-year toxicity in 4/67 patients (6%). Three patients (4.4%) had grade 3 urinary toxicity. Grade 2 acute digestive toxicity was observed in 10/67 patients (14.9%) and grade 2 one-year toxicity in 4/67 patients (6%). Patients with prior prostate bed irradiation did not exhibit increased urinary or digestive toxicity. EORTC questionnaire scores at one year did not worsen significantly.CONCLUSIONS:The acute and one-year toxicity of the BLINDED protocol was satisfactory, even in patients with a past history of prostatic irradiation