ESTRO 37 Abstract book

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ESTRO 37

of longer OS and PFS, and the chemotherapy regimen of PFS (p=0.02); however, nosignificant differences between groups were found in multivariate analysis. Conclusion Weekly cisplatin as compared tothree-weekly cisplatin offers a good toxicity profile, with similar clinical outcomes, with no differences in OS or PFS in our series. EP-1117 Oncologic Safety of De-escalation Compared with Standard Dose in T1-3 Nasopharyngeal Carcinoma Z. Yin 1 , T. Zhao 2 , S. Jiang 3 , P. Wang 4 , Z. Yuan 4 , W. Wang 5 1 Tianjin Medical University Cancer Institute & Hospital, Radiotherapy, tianjin, China 2 Beijing Hospital, Departments of Radiation Oncology, Beijing, China 3 Tianjin Medical University, Department of radiotherapy, Tianjin, China 4 Tianjin Medical University Cancer Hospital, Department of Radiotherapy, Tianjin, China 5 Tianjin Medical University Cancer Hospital, Department of Radiotherapy, Tianjin, China Purpose or Objective Excellent local control (higher than 90%) in patients with T1-3 nasopharyngeal carcinoma (NPCs) in the era of intensity modulated radiotherapy (IMRT), may lead to local dose de-escalation in selected patients. In order to assess the oncologic safety of de-escalated dose compared with standard dose in T1-3 NPCs treated with IMRT, a retrospective propensity score analysis was conducted. Material and Methods A total of 264 patients diagnosed with T1-3NanyM0 nasopharyngeal carcinoma between June 2011 and June 2015 were retrospective analyzed. The median age was 50 years old (14-75 years old), 66 patients were female and 198 were male. All the patients were treated with IMRT, with or without systemic chemotherapy. The prescription IMRT dose in our institution is 69.96Gy/2.12Gy/33F to primary tumor and cervical metastatic lymph nodes, 60.06Gy/1.82Gy/33F to high risk target and 50.96Gy/1.82Gy/28F to low risk target. Results With a median follow-up time of 38 months. The 3-year locoregional failure free survival (LRFS), distant metastasis free survival (DMFS), disease free survival (DFS), and overall survival (OS) were 90.5%, 86.2%, 77.1% and 90.8%, respectively. 30 patients received IMRT dose less than prescription dose, categorized as dose de- escalation group, with a median dose of 64Gy. And 234 patients received exactly prescription dose were categorized as standard dose group, with a median dose of 70Gy. The 3-year LRFS rate and 3-year OS rate were 90.0% and 90.9% in standard dose group, while 95.0% and 90.0% in dose de-escalation group ( p =0.508 for LRFS and 0.955 for OS). Propensity scores were computed (30 patients for dose de-escalation group and 60 patients in standard dose group), and there is no significant difference in 3-year LRFS and 3 year OS between two groups (88.9% and 91.5% in standard dose group; 95.0% and 90.0% in dose de-escalation group, p =0.351 for LRFS and 0.918 for OS). In the multivariate analysis, no prognostic factor, including age, gender, T stage, N stage, RT dose, systemic chemotherapy, was associated with locoregional failure. Conclusion The results of a moderate de-escalation dose (the median dose was 64Gy) in selected patients (staged in T1-3) treated with IMRT are comparable to those of standard prescription dose (70Gy). EP-1118 Prediction of distant metastasis by simulating CT radiomics feature in nasopharyngeal carcinoma Z. Yin 1 , J. Zhang 2 , W. Wang 2 1 Tianjin Medical University Cancer Institute & Hospital,

Conclusion Results showed excellent short-term outcome and limited radiation-related side effects in pts treated with a MB approach. A longer follow-up is required to confirm these promising preliminary results EP-1116 Cisplatin-based chemotherapy plus radiotherapy for head and neck carcinoma. A. Hervas Moron 1 , J. Dominguez 1 , M. Martín 1 , M. Vallejo 1 1 Hospital Ramon y Cajal, Radiation Oncology, Madrid, Spain Purpose or Objective To compare the outcome and acute toxicity profile of radiotherapy plus weekly or three-weekly cisplatin in the treatment of locally advanced squamous cell carcinoma One-hundred and twenty-two patients with locally advanced head and neck carcinoma were treated with combined radiotherapy and chemotherapy using a cisplatin regimen in out institution over a 12-year period. Overall survival (OS) and progression-free survival (PFS) were calculated using Kaplan-Meier and multivariate Cox regression analysis was used to assess differences. Results Mean age at diagnosis was 59 years (range 42-82). Mean dose to gross target volume was 70 Gy and 50 Gy to clinical target volume. Weekly cisplatin (40 mg/m 2 ) was used in 96 patients and three-weekly cisplatin (100mg/m 2 ) in 26. Mean follow-up was 33.5 months (2- 157). No significant differences in grade 3-4 mucositis (27.2% vs. 40%), epithelitis (6.2% vs. 8.3%) or neutropenia (13.2% vs. 16%) were found. OS at 2 and 5 years was 70.3% and 50% respectively, and PFS at 2 and 5 years was 72.5% and 64.1%. In univariate analysis, stage III (p=0.01) and larynx location (p=0.005) were significant predictors of the head and neck. Material and Methods