A Large, Multicenter, Retrospective Study on Efficacy and Safety of Stereotactic Body Radiotherapy (SBRT) in Oligometastatic Ovarian Cancer (MITO RT1 Study): A Collaboration of MITO, AIRO GYN, and MaNGO Groups.

Recent studies have reported improvement of outcomes (progression-free survival, overall survival, and prolongation of androgen deprivation treatment-free survival) with stereotactic body radiotherapy (SBRT) in non-small cell lung cancer and prostate cancer. The aim of this retrospective, multicenter study (MITO RT-01) was to define activity and safety of SBRT in a very large, real-world data set of patients with metastatic, persistent, and recurrent ovarian cancer (MPR-OC).

The endpoints of the study were the rate of complete response (CR) to SBRT and the 24-month actuarial local control (LC) rate on "per-lesion" basis. The secondary endpoints were acute and late toxicities and the 24-month actuarial late toxicity-free survival. Objective response rate (ORR) included CR and partial response (PR). Clinical benefit (CB) included ORR and stable disease (SD). Toxicity was evaluated by the Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC) and Common Terminology Criteria for Adverse Events (CTCAE) scales, according to center policy. Logistic and Cox regression were used for the uni- and multivariate analysis of factors predicting clinical CR and actuarial outcomes.

CR, PR, and SD were observed in 291 (65.2%), 106 (23.8%), and 33 (7.4%) lesions, giving a rate of CB of 96.4%. Patient aged ≤60 years, planning target volume (PTV) ≤18 cm3 , lymph node disease, and biologically effective dose α/β10 > 70 Gy were associated with higher chance of CR in the multivariate analysis. With a median follow-up of 22 months (range, 3-120), the 24-month actuarial LC rate was 81.9%. Achievement of CR and total dose >25 Gy were associated with better LC rate in the multivariate analysis. Mild toxicity was experienced in 54 (20.7%) patients; of 63 side effects, 48 were grade 1, and 15 were grade 2. The 24-month late toxicity-free survival rate was 95.1%.

This study confirms the activity and safety of SBRT in patients with MPR-OC and identifies clinical and treatment parameters able to predict CR and LC rate.

This study aimed to define activity and safety of stereotactic body radiotherapy (SBRT) in a very large, real life data set of patients with metastatic, persistent, recurrent ovarian cancer (MPR-OC). Patient age <60 years, PTV <18 cm3 , lymph node disease, and biologically effective dose α/β10 >70 Gy were associated with higher chance of complete response (CR). Achievement of CR and total dose >25 Gy were associated with better local control (LC) rate. Mild toxicity was experienced in 20.7% of patients. In conclusion, this study confirms the activity and safety of SBRT in MPR-OC patients and identifies clinical and treatment parameters able to predict CR and LC rate.

The oncologist. 2019 Oct 10 [Epub]

Gabriella Macchia, Roberta Lazzari, Nicoletta Colombo, Concetta Laliscia, Giovanni Capelli, Giuseppe Roberto D'Agostino, Francesco Deodato, Ernesto Maranzano, Edy Ippolito, Sara Ronchi, Fabiola Paiar, Marta Scorsetti, Savino Cilla, Rossana Ingargiola, Alessandra Huscher, Anna Maria Cerrotta, Andrei Fodor, Lisa Vicenzi, Donatella Russo, Simona Borghesi, Elisabetta Perrucci, Sandro Pignata, Cynthia Aristei, Alessio Giuseppe Morganti, Giovanni Scambia, Vincenzo Valentini, Barbara Alicja Jereczek-Fossa, Gabriella Ferrandina

Fondazione "Giovanni Paolo II," Unità Operativa di Radioterapia, Università Cattolica del Sacro Cuore, Campobasso, Italy., Division of Radiotherapy, IEO European Institute of Oncology, IRCCS, Milan, Italy., Division of Medical Gynecologic Oncology, IEO European Institute of Oncology, IRCCS and University of Milan-Bicocca, Milan, Italy., Department of Translational Medicine, Division of Radiation Oncology, University of Pisa, Pisa, Italy., Department of Human Sciences, Society and Health, University of Cassino and Southern Lazio, Cassino, Italy., Department of Radiotherapy and Radiosurgery, Humanitas Clinical and Research Hospital, IRCSS, Rozzano, Milan, Italy., Radiation Oncology Centre, S. Maria Hospital, Terni, Italy., Department of Radiation Oncology, Campus Bio-Medico University, Rome, Italy., Fondazione "Giovanni Paolo II," Unità Operativa di Fisica Medica, Università Cattolica del Sacro Cuore, Campobasso, Italy., U.O. di Radioterapia Oncologica "Guido Berlucchi," Fondazione Poliambulanza, Brescia, Italy., Radiotherapy Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy., Department of Radiation Oncology, San Raffaele Scientific Institute, Milan, Italy., Department of Oncology and Radiotherapy, Azienda Ospedaliera Universitaria Ospedali Riuniti, Ancona, Italy., Radiotherapy Unit, Ospedale "Vito Fazzi", Lecce, Italy., Radiotherapy Department, Azienda USL Toscana sud est, San Donato Hospital-Arezzo, Italy., Radiation Oncology Section, University of Perugia and Perugia General Hospital, Perugia, Italy., Istituto Nazionale Tumori di Napoli, Fondazione Pascale IRCCS, Naples, Italy., Department of Experimental, Diagnostic and Specialty Medicine - DIMES, University of Bologna, S. Orsola-Malpighi Hospital, Bologna, Italy., Fondazione Policlinico Universitario A. Gemelli, IRCCS, Unità Operativa Complessa Ginecologia Oncologica, Dipartimento per la Salute della Donna e del Bambino e della Salute Pubblica, Roma, Italy.