ESTRO 2021 Abstract Book

S139

ESTRO 2021

OC-0207 Long-term results of peri-transplant RT in Hodgkin’s lymphomas: results from a multi-center study M. Levis 1 , B. Campbell 2 , F. Matrone 3 , G. Furfaro 1 , L. Grapulin 4 , A. Di Russo 5 , M. Buglione 6 , I. Iamundo De Cumis 7 , G. Simontacchi 8 , P. Ciammella 9 , A. Magli 10 , G. Pascale 11 , S. Meregalli 12 , M. MacManus 2 , G. Fanetti 3 , F. De Felice 4 , A. Alghisi 6 , M.A. Deidda 7 , M. Manicone 9 , G. Ciccone 13 , A.R. Filippi 14 , U. Ricardi 1 1 University of Torino, Department of Oncology, Torino, Italy; 2 Peter MacCallum Cancer Centre, Department of Radiation Oncology, Melbourne, Australia; 3 Centro di Riferimento Oncologico di Aviano - IRCCS, Department of Radiation Oncology, Aviano, Italy; 4 Sapienza University, Department of Radiation Oncology, Roma, Italy; 5 Fondazione IRCCS Istituto Nazionale dei Tumori di Milano, SC Radioterapia, Milano, Italy; 6 Brescia University, Department of Radiation Oncology, Brescia, Italy; 7 Azienda Ospedaliera Brotzu, Department of Radiation Oncology, Cagliari, Italy; 8 Careggi Hospital, Department of Radiation Oncology, Firenze, Italy; 9 AO-IRCCS Arcispedale Santa Maria Nuova, Department of Radiation Oncology, Reggio Emilia, Italy; 10 Azienda Ospedaliero Universitaria Santa Maria della Misericordia, Department of Radiation Oncology, Udine, Italy; 11 Istituto Romagnolo per lo studio dei tumori - IRCCS, Department of Radiation Oncology, Meldola, Italy; 12 Ospedale San Gerardo, Department of Radiation Oncology, Monza, Italy; 13 Città della Salute e della Scienza - CPO Piemonte, Clinical Epidemiology, Torino, Italy; 14 Fondazione IRCCS Policlinico San Matteo and University of Pavia, Department of Radiation Oncology, Pavia, Italy Purpose or Objective In this multicenter collaboration, we report real-world data in the largest published series of long-term outcomes for patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL) treated with peri-transplant radiotherapy (pt-RT) and high-dose chemotherapy with autologous stem cell transplant (ASCT). Materials and Methods We conducted a multi-institutional retrospective analysis, including data from 11 Italian and 1 Australian Institutions. Eligibility required a histological diagnosis of HL, receipt of ASCT plus pt-RT between 2004 and 2014 for R/R HL and age ≥18 years at time of ASCT. All patients received salvage chemotherapy (sCT) for maximum debulking prior to ASCT. Metabolic responses to sCT, ASCT and pt-RT were scored according to the Lugano Classification. Partial metabolic response or stable disease were defined as incomplete response, while progressive disease was defined as refractory. All patients were required to receive pt-RT immediately before or within 6 months after the ASCT date. Primary endpoint was overall survival (OS) and secondary endpoint was progression-free survival (PFS). Time to event endpoints were calculated from the date of ASCT with the Kaplan-Meier method, and were compared among subgroups using the log-rank test. Univariate and Multivariable (MVA) Cox proportional hazards were calculated to estimate the effect of covariates on patients’ outcome. Results 131 patients were eligible: 68 (52%) were male, median age at ASCT was 32 (range, 18-70) years. At time of diagnosis with R/R HL, 92 (70%) patients had limited (stage I-II) disease, and 10 (8%) patients had bulky disease. Before ASCT, complete metabolic response (CMR) was observed in 50 (38%) patients, incomplete response in 53 (40%) and refractory disease in the remaining 28 (21%). Peritransplant-RT was given pre-ASCT in 32 patients (24%) and post-ASCT in 99 (76%); median prescribed dose was 30.6 Gy (range, 20-44 Gy). With median follow up of 60 months, 3- and 5-year OS were 84% and 77%, while 3- and 5-year PFS were 75% and 72%, respectively ( Figure ). On MVA, advanced stage at relapse (HR 4.07, p = 0.01), involvement of >3 nodal areas (HR 3.67, p = 0.04), incomplete metabolic response before ASCT (HR 2.88, p = 0.02) and after pt-RT (HR 4.34, p <0.01) had a negative impact on OS. An incomplete metabolic response to pt-RT (HR 7.00, p <0.01) and being treated with ASCT before 2010 (HR 4.09, p = 0.01) negatively affected PFS. The timing of pt-RT (pre- ASCT vs post-ASCT) did not have an impact on OS or PFS.