Abstract Book

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ESTRO 37

local relapse (p < 0.05). From these miRNAs, it was developed four miRNAs model (miR-212-3p, miR-331-5p, miR-1228-3p, and miR-4786-3p) that was highly associated with the local progression risk (HR = 2.72, 95%CI for HR (1.78-4.16), p < 5.87*10-7, Cox regression analysis). Kaplan-Meier analysis also revealed that Risk Score calculated based on this miRNA model was able to stratify patients with early and later local progression/recurrence after RT (p < 1.7*10-7, Risk Score threshold = 0.8566632). Conclusion Our data suggest that above miRNAs seem to be very promising molecules able to predict time to local disease progression in HNSCC patients who underwent IMRT. This work was financially supported by the Czech Ministry of Health, Grant no. 15-31627A, Project MZ CR – RVO (MOU, 00209805), and by the Ministry of Education, Youth and Sports of the Czech Republic under Project CEITEC 2020 (LQ1601). EP-2291 SUVmax of Primary Lesion in 18-F- Fluorodeoxyglucose PET predicts outcome in oral cavity cancer. P. Nenclares Peña 1 , M. Alarza Cano 1 , L. Asiaín Azcárate 1 , A. Hernández Martínez 2 , A. Ruíz Alonso 1 , J.F. Pérez- Regadera Gómez 1 1 Hospital Universitario 12 de Octubre, Radiation Oncology, Madrid, Spain 2 Hospital Universitario 12 de Octubre, Nuclear Medicine, Madrid, Spain Purpose or Objective 18 F-Fluorodexoyglucose positron emission tomography (18- FDG-PET) is widely used in the diagnosis and staging of head and neck cancer. As a functional imaging study, 18- FDG-PET may have a predictive value in long-term prognosis. The aim of this study was to investigate the clinical usefulness of the pretreatment 18-FDG-PET/CT parameters in predicting prognosis for patients with locally advanced oral cavity cancer (OCC). Material and Methods From October 2009 through April 2016, 42 non-metastatic OCC patients who underwent 18-FDG-PET before treatment were enrolled and reviewed retrospectively. 18-FDG-PET parameters were correlated with clinicopathologic parameters and prognostic data. Student T test or Mann-Whitney were used to evaluate the distribution of SUVmax values. Analysis of survival was performed using Log-rank test and Cox regression analysis. The best cut-off value of SUVmax was determined using the p-mimimum value strategy. Results Mean tumor and lymph node SUVmax values were 23.93 (range 4.22-27.03) and 9.69 (range 3.53-27.03), respectively. Tumor-SUVmax correlated with the presence of contralateral lymph nodes (p=0.049). With a median follow-up of 23 months, median overall survival (OS) and disease-free survival were 21 and 8 months, respectively. Univariate analysis showed higher tumor- SUVmax, stage and age were factors predicting for significantly poorer OS (p=0.032, p=0.011, p= 0.045, respectively). In multivariate analysis, tumor-SUVmax was an independent predictive factor for OS (HR: 1.04, CI95% 1.01-1.09, p=0.039). The best cut-off value of tumor-SUVmax for predicting survival was 22.2 (p=0.049). Conclusion The results of this study indicate that tumor-SUVmax may function as an independent predictive factor for

Conclusion Cetuximab-ABT-199 couple combined with photon radiation significantly inhibited spheroid growth of SQ20B and FaDu cell lines, targeting both parental and CSCs subpopulations. EP-2290 The Role of MicroRNAs Expression Model in Head and Neck Squamous Cell Carcinoma. M. Slavik 1 , P. Ahmad 2 , J. Sana 2 , T. Shatokhina 3 , T. Kazda 1 , M. Hermanova 3 , P. Slampa 1 , O. Slaby 2 1 Masaryk Memorial Cancer Institute and Faculty of Medicine- Masaryk University, Radiation Oncology, Brno, Czech Republic 2 Masaryk University, Central European Institute of Technology, Brno, Czech Republic 3 St. Anne´s University Hospital and Faculty of Medicine- Masaryk University, 1st Department of Pathological Anatomy, Brno, Czech Republic Purpose or Objective The aim of this study was to discover a set of MicroRNAs (Mirnas) which will predict the radiation therapy response in head and neck squamous cell cancer (HNSCC) patients and be able to predict the locoregional control ( LRC) and classify these patients according to the time to local progression. Material and Methods We retrospectivly analyzed global miRNA expression profiles in 43 FFPE tumor samples from HNSCC patients treated by definitive intensity modulated radiotherapy. Patients were divided into two groups according to their time to local disease progression as follows. Short [n = 22; median 5.1 months (1.3, 18.6)] vs. long [n = 21; 60.4 (46.8, 98.8)] LRC groups: sex – 18 (82%) male, 4 (18%) female vs. 19 (90%) male, 2 (10%) female; age at diagnosis – median 57,5 vs. 58,3 years; diagnosis –SCCs of oral cavity 4 (18%), hypopharynx 3 (14%), larynx 3 (14%), oropharynx 12 (54%) vs. 3 (14%), 3 (14%), 4 (19%), 11 (53%); stage – IV 19 (86%), III (14%) vs. IV 13 (62%), III 7 (33%), II 1 (5%); CD44-positive – 4 (18%) vs. 2 (10%); EGFR- positive – 14 (64%) vs. 10 (48%); p16-positive – 6 (27%) vs. 8 (38%). The miRNA expression analyses were carried out by the hybridization technology GeneChip miRNA 4.0 array (Affymetrix). All data were pre-processed and further analyzed by the software packages included in the R/Bioconductor, all data were log2-transformed. Results Twenty-four miRNAs that were significantly differentially expressed between both groups (p < 0.05; Average Expression > 1; Average logFold Change = 0.42). Similarly, 24 miRNAs were significantly associated with the time to