ESTRO 2020 Abstract Book

S84 ESTRO 2020

Of the 376 patients, 121 had VSVZ involved, 62 had CC involved and 43 had SGZ involved and remaining 150 had cortical involvement and the latter served as controls. Overall median age was 60.4 years, median Karnofsky performance score (KPS) was 80 and median tumor volume was 34.7 cm 3 . Gross total resection (GTR) was seen in 50.6% and subtotal resection in 38.1% and rest were unresectable. On multivariate cox analyses, VSVZ was found to be an independent factor for poor OS and PFS. Besides, increasing age, lower KPS, less than GTR status were associated independent factors for reduced survival. Conclusion Patients with GBMs contacting the VSVZ and SGZ neurogenic zones exhibit divergent clinical patterns of tumor recurrence and survival and VSVZ involvement are associated with early recurrences and lower survival. VSVZ has a rich stem cell and growth factor microenvironment and these structures can be considered as organs at risk in uninvolved disease for probably better outcomes. PD-0174 Predictive factors for local and distant brain control and survival after SRT of brain metastases K. Holub 1,23 , G. Louvel 2 1 Universitat de Barcelona- Hospital Clinic de Barcelona, Radiation Oncology, Barcelona, Spain ; 2 Gustave Roussy, Radiation Oncology, Villejuif- Paris, France ; 3 SEOR-CRIS Fundation Purpose or Objective Brain metastases (BMs) are the most common adult intracranial tumors with the growing prevalence. Stereotactic radiotherapy (SRT) has greatly improved their local control (LC), but scores to predict distant control (DC) and overall survival (OS) after SRT are lacking. This study aims to investigate the factors related with local and distant brain progression free survival (LPFS, DPFS), OS and survival limited by neurological death in patients with BMs treated with upfront or post-surgical SRT. Material and Methods The data of 652 consecutive adult patients with 1565 newly diagnosed BMs from histologically confirmed solid tumors, treated with SRT between January 2012 and December 2018 in a large European cancer centre were retrospectively reviewed. In order to evaluate the predictive factors for LPFS, DPFS and OS, the following variables were evaluated: primary tumor histology, time to BMs diagnosis (> 6 months), BM location, gross tumor volume (GTV), planning target volume (PTV), single BM (vs. multiple), total dose of SRT ≤ 20Gy, whole brain radiotherapy (WBRT) prior to SRT, number of SRT fractions. Survival outcomes of patients with upfront and postoperative SRT were analysed separately. All statistical tests were two-sided (p<0.05), Kaplan-Meier’s and Cox regression models were used applied (SPSS v.23). Results SRT was administrated to 567 patients as an upfront treatment of 1399 BMs and to 156 patients with 166 postoperative cavities; 83 patients received both post- surgical and upfront SRT to different lesions. Median age at SRT was 60.3years. Most frequent histologies were NSCLC (267p, 40.9%), melanoma (130p, 19.9%), breast (70p, 10.7%), renal (48p, 7.4%), and colorectal cancer (21p, 3.2%). In patients treated with upfront SRT, lower LPFS was associated with melanoma and GTV>1.5cm3, while breast cancer determined better LC. In terms of DPFS, NSCLC histology was prognosticator of worse LC, while single BM, melanoma and renal cancer histology, and WBRT prior to SRS determined better DC. Superior mOS was observed in patients with single BM, control of extracraneal disease at the time of SRT and time to BMs diagnosis>6m. In patients with postoperative SRT, LC was better in small lesions (PTV<30.0cm3, p=0.033), while DPFS was nearly 5 times longer in single BM compared with multiple BMs (36.7m vs. 7.7m, p=0.000). In a cohort of

patients whose death was determined by brain progression, single BMs (p=0.012) and smaller lesions (PTV < 30.0cm 3 , p=0.000) were associated with better mOS. Infratentorial BM location was associated with worse mOS (9.7 months vs. 18.9 months in supratentorial BMs, p=0.008). Conclusion Our results on the impact of primary tumor histology, number, size and location of BMs, and characteristics of local radiation treatment on LPFS, DPFS and OS add new evidence about SRT efficacy, which may help to refine the selection of patients who benefit more from this treatment and to establish the predictive scores evaluating the risk of local and distant progression after SRT. PD-0175 TTIRS trial:a retrospective analysis of the association between TT or IT and RS for BM from NSCLC E. Olmetto 1 , S. Scoccianti 1 , R. Di Franco 2 , P. Anselmo 3 , G. Beltramo 4 , C. Mantovani 5 , M.F. Osti 6 , V. Pinzi 7 , N. Giaj- Levra 8 , A. Bruni 9 , P. Matteucci 10 , S. Pedretti 11 , E. Giudice 12 , P. Tini 13 , M. Krengli 14 , P. Ciammella 15 , F. Pasqualetti 16 , M. Trignani 17 , A. Merlotti 18 , V. Borzillo 2 , D. Franceschini 19 , E. Maranzano 3 , R. Umberto 5 , N. Pierina 19 , V. Scotti 1 1 University of Florence, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, Firenze, Italy ; 2 Istituto Nazionale Tumori - Fondazione G. Pascale, Department of Radiotherapy, Naples, Italy ; 3 Radiotherapy Oncology Centre S. Maria Hospital, Department of Radiotherapy, Terni, Italy ; 4 Cyberknife Centro Diagnostico Italiano, Department of Radiothrapy, Milan, Italy ; 5 Radiotherapy unit- University of Turin, Department of Oncology, Turin, Italy ; 6 Uoc radioterapia Aou sant’Andrea facoltà medicina e psicologia Universita Sapienza, Department of Radiotherapy, Rome, Italy ; 7 Uo radioterapia Fondazione IRCCS istituto neurologico Carlo Besta, Department of Radiotherapy, Milan, Italy ; 8 IRCCS Ospedale Sacro Cuore Don Calabria, Deaprtment of advanced radiation oncology, Verona, Italy ; 9 Radiotherapy Unit- University Hospital of Modena, Department of Oncology and Hematology, Modena, Italy ; 10 Radioterapia Oncologica Campus Biomedico, Department of Radiotherapy, Rome, Italy ; 11 ASST Spedali Civili di Brescia e Università degli studi di Brescia- U.O. Radioterapia oncologica, Department of Radiotherapy, Brescia, Italy ; 12 UOC di Radioterapia- Policlinico Universitario Tor Vergata, Departmnt of Onco- Haematology, Rome, Italy ; 13 Radioterapy unit- University of Siena, Department of Radiotherapy, Siena, Italy ; 14 Radiation Oncology- University Hospital Maggiore della Carità, Department of Radiotherapy, Novara, Italy ; 15 Radioterapia Oncologica- AUSL-IRCCS Reggio Emilia, Department of Radiotherapy, Reggio Emilia, Italy ; 16 Radiation Oncology- Azienda Ospedaliero Universitaria Pisana, Department of Radiotherapy, Pisa, Italy ; 17 U.O.C. Radioterapia Oncologica- Ospedale Clinicizzato SS Annunziata- UniversitàChieti G.D'Annunzio, Department of Radiotherapy, Chieti, Italy ; 18 Radiation Oncology A.S.O. S.Croce e Carle, Department of Radiotherapy, Cuneo, Italy ; 19 Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, Rozzano, Italy Purpose or Objective To investigate the association between concomitant RadioSurgery (RS) and Immunotherapy (IT) or Targeted Therapy (TT) for the treatment of brain metastases (BM) from Non Small Cell Lung Cancer (NSCLC). Aims of the study were Local Progression free Survival (L-PFS), Distant Progression Free Survival (D-PFS), Overall Survival (OS) and Safety. This a multicenter study by Brain and the Thoracic Oncology Group of Airo (Italian Association of Radiation Oncology)