Matteo Augugliaro1, Giulia Marvaso2, Raffaella Cambria3, Matteo Pepa4, Vincenzo Bagnardi5, Samuele Frassoni5, Floriana Pansini3, Damaris Patricia Rojas1, Francesca Colombo2, Cristiana Iuliana Fodor1, Gennaro Musi6, Giuseppe Petralia7, Ottavio De Cobelli6, Federica Cattani3, Roberto Orecchia8, Dario Zerini1, Barbara Alicja Jereczek-Fossa2. 1. Division of Radiation Oncology, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy. 2. Division of Radiation Oncology, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy; Department of Oncology and Hemato-oncology, University of Milan, Via Festa del Perdono 7, 20122 Milan, Italy. 3. Unit of Medical Physics, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy. 4. Division of Radiation Oncology, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy. Electronic address: matteo.pepa@ieo.it. 5. Department of Statistics and Quantitative Methods, University of Milan-Bicocca, Piazza dell'Ateneo Nuovo, 1, 20126 Milan, Italy. 6. Department of Oncology and Hemato-oncology, University of Milan, Via Festa del Perdono 7, 20122 Milan, Italy; Division of Urology, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy. 7. Department of Oncology and Hemato-oncology, University of Milan, Via Festa del Perdono 7, 20122 Milan, Italy; Division of Radiology, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy. 8. Scientific Direction, IEO, European Institute of Oncology IRCCS, Via Ripamonti 435, 20141 Milan, Italy.
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.
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.