Abstract book - ESTRO meets Asia

S91 ESTRO meets Asia 2018

the follow-up after 2 years and remaining six patients are still under follow-up. Toxicity profiles were really good, with no acute toxicity were documented during the treatment and grade one late GI-toxicity was documented for two patients during follow-up. Conclusion SBRT with very high precision treatment modality can be safely delivered here in Bangladesh with very good therapeutic outcome and lesser toxicities in Hepatocellular carcinoma patients. PO-222 Evaluating the Optimal Radiation Dose for Definitive CCRT for Esophageal Squamous cell carcinoma T. Ke 1 , J. Que 1 1 Chi Mei Medical Center, Radiation oncology, Tainan, Taiwan Purpose or Objective The optimal radiation dose for definitive concurrent chemoradiotherapy (CCRT) in esophageal squamous cell carcinoma (ESCC) has long been debated. In this study we evaluated if doses greater than conventional radiation dose ( ≦ 50.4 Gy) are beneficial in terms of tumor control, tumor response, overall survival (OS) and disease-free survival (DFS). Material and Methods The database of patients diagnosed with esophageal squamous cell carcinoma from 2007 to 2015 were obtained in a medical institution. A total of 84 patients were retrospectively analysed (Figure 1) All categorical variable was compared using Chi-square test. The risk of OS and DFS were estimated using Cox proportional hazards regression, and Kaplan-Meier plot presented the trend of OS and DFS with log-rank test for comparing the difference. All significance levels were set at a p = <0.05.

Conclusion Tumor response might be improved by escalated radiation dose greater than 50.4 Gy, when delivered with IMRT- based definitive concurrent chemoradiotherapy in the esophageal squamous cell carcinoma. Furthermore, the overall survival and disease-free survival also showed better outcome in those who acquired complete response after IMRT-based definitive concurrent chemoradiotherapy. Our study suggested tumor complete response related to the better prognosis. Although higher radiation dose does not show any impact on overall survival, disease-free survival rate nor does it improve locoregional failure as well as distant failure. More studies are warranted to confirm the positive relation between complete response and overall survival or disease-free survival. PO-223 Prognostic value of volumetric parameters of 18F-FDG PET/CT in esophageal cancer: a meta-analysis Y. Kim 1 , S. Han 2 , S. Woo 3 , C.H. Suh 4 , J.J. Lee 2 1 Kangwon National University Hospital, Radiation Oncology, Chuncheon, Korea Republic of 2 Asan Medical Center, Nuclear Medicine, Seoul, Korea Republic of 3 Seoul National University College of Medicine, Radiology, Seoul, Korea Republic of 4 Asan Medical Center, Radiology, Seoul, Korea Republic of Purpose or Objective To perform a systematic review and meta-analysis on the prognostic value of metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from pretreatment 18 F-FDG PET in patients with esophageal cancer. Material and Methods Pubmed and EMBASE databases were searched up to April 12, 2018 for studies which evaluated MTV or TLG as a prognostic factor in esophageal cancer with overall survival (OS) and event-free survival (EFS) as the endpoints. Hazard ratios (HRs) were meta-analytically pooled using the random-effects model. Multiple subgroup analyses based on clinicopathological and PET variables were performed. Results Sixteen studies with 1294 patients were included. The pooled HRs of MTV and TLG for OS were 2.26 (95% CI, 1.73– 2.96) and 2.23 (95% CI, 1.73–2.87), respectively. Regarding EFS, the pooled HRs of MTV and TLG were 2.03 (95% CI, 1.66–2.49) and 2.57 (95% CI, 1.82–3.62), respectively. MTV were significant prognostic factors for OS consistently across the multiple subgroups classified by stage, histologic subtype, treatment, delineation of VOI, and determination method of cut-off value with pooled HRs ranging from 1.96 to 2.54. Conclusion MTV and TLG on pretreatment 18 F-FDG PET were significant prognostic factors in patients with esophageal cancer. As prognostic biomarkers, volumetric metabolic parameters may bolster the role of 18 F-FDG PET in management of esophageal cancer. PO-224 Skeletal muscle depletion predicts toxicities and outcomes in patients with gastric cancer W. Yang 1 , F. Xia 1 , J. Wang 1 , R. Hu 1 , M. Zhou 1 , G. Li 1 , Y. Yuan 1 , Z. Zhang 1

Results Escalated radiation dose (>50.4 Gy) group achieved a higher complete response rate than the conventional radiation dose group ( ≦ 50.4 Gy) (p=.002). (Table 1) Patients who had complete response also had better overall survival (p=.05) and disease-free survival (p=.04) than those who without complete tumor response after IMRT-based definitive concurrent chemoradiotherapy. However, no significant differences were found between escalated dose and conventional dose in overall survival (p=0.214) and disease-free survival (p= 0.264). Failure pattern including local regional failure and distant failure (p=0.424) does not show any significant differences either between the two radiation doses.