ESTRO 37 Abstract book

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ESTRO 37

compared between different treatment modality and EBV viral load. Results Baseline characteristics between CCRT and IndCT-RT were no significant differences except for a higher percentage of N2 disease in the IndCT-RT subgroup (92.4% vs. 80.0%, P=0.0005). Both treatment modality resulted in similar relapse rates (20.0% vs. 17.5%, P=0.5566). The overall survival (OS, P=0.1980), progression-free survival (PFS, P=0.5339), distant metastasis failure-free survival (DMFFS, P=0.8870), and locoregional failure-free survival (LRFFS, P=0.3516) between CCRT and IndCT-RT revealed no statistically significant difference. However, patients with a high viral load experienced a higher relapse rate (33.0% vs. 12.4%, P<0.0001) and worse OS (5-year rate, 79.0% vs. 92.8%, P<0.0001), PFS (73.7% vs. 88.4%, P<0.0001), DMFFS (80.2% vs. 95.0%, P<0.0001), and LRFFS (85.6% vs. 92.6%, P=0.0045) than those with a low viral load. Conclusion IndCT-RT can reach the same treatment outcome as the current standard CCRT for stage III NPC patients. The pretreatment EBV DNA level identified a subgroup of patients, who presented with a higher viral load and suffered from significantly worse survivals. Strengthen treatment intensity for these subgroup patients deserves to study in future trials. EP-1136 Interaction of chemotherapy with radiation and surgery in nasal cavity and nasal sinus cancer T. Zhao 1 , Z. Yin 2 , G. Li 1 1 Beijing Hospital, radiation department, Beijing, China 2 Tianjin Medical University Cancer Institute & Hospital, Radiation department, Tianjin, China Purpose or Objective To evaluate the necessity of chemotherapy in nasal cavity and nasal sinus carcinoma, and to clarify the influence of surgery or radiotherapy on the outcome of chemotherapy. Material and Methods The Surveillance, Epidemiology, and End Results (SEER) database was used to identify 4131 patients with squamous cell carcinoma, adenocarcinoma, adenosquamous carcinoma, undifferentiated carcinoma, or adenoid cystic carcinoma in nasal cavity and nasal sinus between 2004 and 2014. Chi-square analysis was used to evaluate distribution of patient and tumor related factors within treatment groups. The Kaplan- Meier method was utilized to calculate overall survival. Log-rank method was used in univariate analysis and Cox- regression model was used to perform the multi-covariate analysis. All statistical tests were two-sided. Results In univariate analysis, T stage, N stage, pathology type, pathology grade and primary site (nasal cavity or nasal sinus) were prognostic factors (p<0.05 for all). Receiving radiotherapy or surgery predicted a better prognosis (p<0.05 for two). Chemotherapy was predictive of a worsen prognosis (p=0.03). In multivariate analysis, chemotherapy, radiotherapy, surgery, T stage, N stage, pathology type, pathology grade and primary site were all independent prognostic factors (p<0.05 for all).However, chemotherapy was marginally predictive of a better prognosis(p=0.049). Subgroup analyses were performed. For 882 patients treated with radiotherapy and no surgery, patients with T3 or N2 stage benefited from chemotherapy (5y-OS: 40.8% vs 17.8%, p=0.007; 28.4% vs 15.2%, p=0.036), while patients with T2 or N0 stage who received chemotherapy showed even worse OS (5y-OS: 27.4% vs 64.0%, p=0.013; 35.0% vs 88.0%, p=0.007). For 1190 patients who received surgery only, patients with N0 stage who received chemotherapy showed worse OS than those who received no chemotherapy (5y-OS: 63.1% vs 74.1%, p=0.016). For 1615 patients who received both

Conclusion p16-positive oropharyngeal cancer revealed to be a distinctive disease entity. Especially, extranodal extension had strong prognostic value for p16-negative oropharyngeal cancer, on the other hand, was not significantly relevant for p16-positive patients. Therefore, identical indication for adjuvant radiotherapy should not be applied to both p16-positive and p16- negative patients. Deintensified adjuvant strategy for p16-positive oropharyngeal squamous cell carcinoma seems to be needed. EP-1135 Effects of different treatment and EBV viral load in stage III nasopharyngeal carcinoma patients J.C. Lin 1 , W. Wen-Yi 2 , L. Yi-Chun 1 1 Taichung Veterans General Hospital, Department of Radiation Oncology, Taichung, Taiwan 2 Hung Kuang University, Department of Nursing, Taichung, Taiwan Purpose or Objective To investigate the prognostic impacts of different treatment modality and pretreatment plasma EBV DNA levels in patients with stage III nasopharyngeal carcinoma (NPC). Material and Methods This retrospective study collected 356 previously untreated, pathologically-proven NPC patients with stage III disease. The initial definitive treatment consisted of concurrent chemoradiotherapy (CCRT, n=145) or induction chemotherapy plus radiotherapy (IndCT-RT, n=211). Eighty-four of 356 (23.6%) patients also received post-RT adjuvant chemotherapy. The pre- treatment EBV DNA level was measured by the real-time quantitative polymerase chain reaction. We arbitrarily divided patients into a high (> 1000 copies/mL, n=106) or low (< 1000 copies/mL, n=250) viral load subgroup. Subsequent relapse rates and various survival curves were