Finding safe dose-volume constraints for re-irradiation with SBRT of patients with prostate cancer relapse: The IEO experience. (December 2021)

• Record Type: Journal Article
• Authors: Augugliaro, Matteo; Marvaso, Giulia; Cambria, Raffaella; Pepa, Matteo; Bagnardi, Vincenzo; Frassoni, Samuele; Pansini, Floriana; Patricia Rojas, Damaris; Colombo, Francesca; Iuliana Fodor, Cristiana; Musi, Gennaro; Petralia, Giuseppe; De Cobelli, Ottavio; Cattani, Federica; Orecchia, Roberto; Zerini, Dario; Alicja Jereczek-Fossa, Barbara
• Is Part Of: Physica medica. Volume 92(2021)
• Page Start: 62
• Page End: 68
• Publication Date: 2021-12
• Subjects: AIRO Italian Association of Radiotherapy and Clinical Oncology -- ADT Androgen Deprivation Therapy -- BT Brachytherapy -- b-PFS Biochemical Progression-Free Survival -- CI Confidence Interval -- CT Computed Tomography -- DA Dynamic Arc -- DVH Dose-Volume Histogram -- EBRT External Beam Radiation Therapy -- EORTC European Organisation for Research and Treatment of Cancer -- IGRT Image-guided RT -- IMRT Intensity-modulated RT -- G Grade -- GI Gastrointestinal -- GU Genitourinary -- HR High Risk -- LQ Linear Quadratic -- LR Low Risk -- mpMRI multiparametric Magnetic Resonance Imaging -- EQD2 2 Gy Equivalent Uniform Dose -- OAR Organ at Risk -- OR Odds Ratio -- OS Overall Survival -- PCa Prostate Cancer -- PET Positron Emission Tomography -- PSMA Prostate-specific membrane antigen -- PSA Prostate-Specific Antigen -- PTV Planning Target Volume -- QoL Quality of Life -- RT Radiotherapy -- RTOG Radiation Therapy Oncology Group -- SBRT Stereotactic Body Radiation Therapy -- VMAT Volumetric-Modulated Arc Therapy; Recurrent prostate cancer -- Salvage external beam radiotherapy -- Dosimetric constraints -- Re-irradiation; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2021.11.005
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: Consensus for the management of PCa recurrence following EBRT is lacking. Salvage SBRT represents an effective and safe treatment option. Literature on dosimetric constraints for safe and effective re-irradiation is scarce. The study provides a useful benchmark for re-irradiation planning. Abstract: Aim: The primary aim of this study is to provide preliminary indications for safe constraints of rectum and bladder in patients re-irradiated with stereotactic body RT (SBRT). Methods: Data from patients treated for prostate cancer (PCa) and intraprostatic relapse, from 1998 to 2016, were retrospectively collected. First RT course was delivered with 3D conformal RT techniques, SBRT or volumetric modulated arc therapy (VMAT). All patients underwent re-irradiation with SBRT with heavy hypofractionated schedules. Cumulative dose-volume values to organs at risk (OARs) were computed and possible correlation with developed toxicities was investigated. Results: Twenty-six patients were included. Median age at re-irradiation was 75 years, mean interval between the two RT courses was 5.6 years and the median follow-up was 47.7 months (13.4–114.3 months). After re-irradiation, acute and late G ≥ 2 GU toxicity events were reported in 3 (12%) and 10 (38%) patients, respectively, while late G ≥ 2 GI events were reported in 4 (15%) patients. No acute G ≥ 2 GI side effects were registered. Patients receiving an equivalent uniform dose of the two RT treatments < 131 Gy appeared to be at higher risk of progression (4-yr b-PFS: 19% vs 33%, p = 0.145). Cumulative re-irradiation constraints that appear to be safe are D30% < 57.9 Gy for bladder and D30% < 66.0 Gy, D60 % < 38.0 Gy and V122.1 Gy < 5% for rectum. Conclusion: Preliminary re-irradiation constraints for bladder and rectum have been reported. Our preliminary investigation may serve to clear some grey areas of PCa re-irradiation.