ESTRO 36 Abstract Book

S389 ESTRO 36 _______________________________________________________________________________________________

Material and Methods Patients diagnosed with uveal melanoma from 2004 to 2013 were selected from Surveillance, Epidemiology, and End Results (SEER) database. Propensity-score matching with nearest neighbor 1:1 matching method and inverse probability of treatment weighting (IPTW) using propensity score were used to compare the survival outcome between RT only and surgical resection alone for the treatment of uveal melanoma. Results Overall, 3,291 patients were treated: 2,503 received RT only (RT group) and 788 surgical resections only (surgery group), respectively. After propensity-score matching, 437 patients were identified in each cohort (total N = 874). The RT group had an improved crude 5-year overall survival (OS) rate compared with the surgery group (76 % vs. 60 %, P-value < 0.001) and the 5-year cancer-specific survival (CSS) rate (89% vs. 72 %, P-value < 0.001), respectively. Compared to the surgery group, the RT group was associated with improved OS [hazard ratio (HR) = 0.51, 95% confidence interval (CI) = 0.39 – 0.66, P-value < 0.001] and CSS [HR = 0.37, 95% CI = 0.25 - 0.54, P-value < 0.001] in multivariate Cox proportional hazard analysis, respectively. The survival benefit of the RT group maintained after adjustment with IPTW, both in OS [adjusted HR (AHR) = 0.45, 95% CI = 0.36 - 0.56, P-value < 0.001] and CSS [AHR = 0.27, 95% CI 0.27 - 0.51, P-value < 0.001]. Conclusion To our knowledge, the present study is the first to demonstrate the survival difference according to the treatment modality in uveal melanoma, using both propensity-score matching and weighting methods with the SEER database. The current study suggests that RT might provide a survival advantage over surgery in the treatment of uveal melanoma. PO-0741 Ipilimumab and stereotactic radiosurgery with cyberknife in melanoma brain metastases V. Borzillo 1 , R. Di Franco 1 , S. Falivene 1 , A. Martino 2 , V. Ravo 1 , G. Totaro 1 , F.M. Giugliano 3 , P.A. Ascierto 4 , A.M. Grimaldi 4 , L. Festino 4 , E. Simeone 4 , V. Vanella 4 , F. Cammarota 1 , D. Giannarelli 5 , P. Muto 1 1 Istituto Nazionale Tumori Fondazione Pascale, Radioterapia, Napoli, Italy 2 Seconda Università degli Studi di Napoli, Dipartimento di Diagnostica per Immagini e Radioterapia, Napoli, Italy 3 European Medical Imaging Fondazione Muto-onlus, Radiation Oncology, Casavatore- Naples, Italy 4 Istituto Nazionale Tumori Fondazione Pascale, Struttura Complessa Oncologia Medica Melanoma Immunoterapia Purpose or Objective Ipilimumab(Ipi), an anti-cytotoxic T-lymphocyte- associated antigen 4(CTLA-4) monoclonal antibody, has been shown to improve survival in patients(pts) with advanced melanoma. However, there is a lack of data about the efficacy of Ipi in pts with brain metastases(BMs), as well as about its combination with radiotherapy(RT) and the right sequence of both treatments. The purpose of this study was to evaluate overall survival(OS), local control(LC) of the lesion treated, and intracranial control(IC) in pts with melanoma BMs (MBMs) treated with stereotactic Radiotherapy(SRT)/radiosurgery(SRS) with Cyberknife® and Ipi Material and Methods From December 2012 to May 2016 we treated 63 pts(34 M,29 F) with MBMs. The median age was 61 years (28-81y). 52pts received Ipi: 24 prior-RT(IPI PRE-RT), 7 concomitant- RT and 21 post-RT(IPI POST-RT).11 not received Ipi(NO Oncologica e Terapie Innovative, Napoli, Italy 5 Istituto Nazionale Tumori Regina Elena Roma, Biostatistical Unit, Roma, Italy

Results of the test were validated in 72% of the patients. They were confirmed by histology in 14%, by another imaging technique (MRI, Bone scintigraphy or CT) in 23.2%, by another 18F-Ch-PET in 5% and with a biochemical response after a specific treatment in 48% of them. Result of the test was discordant in 9%. According to this data, 18F-Ch-PET has a Sensibility and Specificity of 97% and 81% respectively. Conclusion 18F-Ch-PET seems to be a very useful diagnostic test for restaging recurrent PCa in selected group of patients, allowing all relapse sites to be evaluated at once. It can also modify treatment management in an important percentage, identifying which ones can be offered a potential curative treatment. In our series, like in previous literature, PSA level, PSAvel and PSAdt are strong predictive factors for positive 18F- Ch-PET. PO-0739 Phase II Trial of Dynamic Dosimetry for prostate brachytherapy: correlation with post-implant MRI/CT PO-0740 Surgery versus Radiotherapy in Uveal Melanoma: SEER Analysis using Propensity Score Matching &IPTW B.S. Jang 1 , J.H. Chang 2 , S.H. Oh 3 , Y.J. Lim 1 , I.H. Kim 4 1 Seoul National University Hospital, Department of Radiation Oncology, Seoul, Korea Republic of 2 SMG-SNU Boramae Medical Center, Department of Radiation Oncology, Seoul, Korea Republic of 3 SMG-SNU Boramae Medical Center, Department of Biostatistics, Seoul, Korea Republic of 4 Cancer Research Institute- Seoul National University College of Medicine, Department of Radiation Oncology, Seoul, Korea Republic of Purpose or Objective The treatment of uveal melanoma includes surgery and radiotherapy (RT). Utilization of RT has been increasing as a strategy for organ preservation, but the survival difference between two modalities has not been reported. Abstract withdrawn Poster: Clinical track: Skin cancer / malignant melanoma