ESTRO 38 Abstract book

S762 ESTRO 38

Baseline Characteristics Characteristic n=10 Age(years) Median(range) 66(43-84) Sex male 4(40%) female 6(60%) ECOG PS 1 1(10%) 2 2(20%) 3 7(70%) Stage Ⅲ 9(90%) Ⅳ 1(10%)

Results The median clinical follow-up time from the beginning of first CT application was 30 months (range, 8-130 months.The incidence of severe lymphopenia was only 1% at control evaluation but it was 93% after CRT (p<.001). The median OS time was 24 months (range, 8-126 months). The 2, 3, and 4-year OS rates were 65%, 59%, and 52%, respectively. There was no statistically significant difference in OS in patients with severe lymphopenia and SIR positivity after CRT ( p =.75, and p =.31, respectively). Additionally, the severity of baseline lymphopenia or lymphopenia at the control evaluation had no effect on OS rates ( p =.75, and p =.92, respectively). Median RFS time was 20 months (range, 6-120 months). The 2, 3, and 4-year RFS rates were 58%, 55%, and 50%, respectively. In univariate analysis, stage 3 disease ( p <.001) and MDLN ratio >20% ( p <.001) had negative effect on OS. In multivariate analysis for OS, stage III disease (p=.041) and MDLN ratio >20% (p=.032).In univariate analysis for RFS, stage 3 disease (p=.001), and MDLN ratio >20% (p=.011) had negative effect. MDLN ratio >20% was the only significant prognostic factor for RFS in multivariate analysis (p=.033).In the ROC analysis, the AUC for mean splenic doses was 0.741 for OS (p=.042) and 0.680 for RFS (p=.050). Mean splenic dose ≥35 Gy was a significant poor prognostic factor for OS and RFS (p=.042, and p=0.50 respectively). Maximum splenic dose ≥58 Gy effected OS unfavorably (p=.050).Volumetric modulated arc therapy (VMAT), intravenous CT, and age ≥65 years were significant predictors for severe lymphopenia. Conclusion Severe lymphopenia could not be accepted as a predictive or prognostic factor for LAGC. Mean and maximum splenic doses should be kept on mind while evaluating the treatment DVHs. Age of patient, iv usage of concomitant CT agent and VMAT are the factors which can influence the ALCs of patients.Disease-related factors such as stage and metastatic lymph node ratio are seen the most important factors. EP-1399 A Pilot Study of Apatinib Combined with SBRT To Advanced Pancreatic Cancer G. MA 1 , M. Shuo 2 , Z. Shuman 1 , X. Li-ang 1 1 4th Hospital Hebei Medical University, Radiotherapy, shijiazhang, China ; 2 Syracuse University, new York, USA Purpose or Objective The primary endpoint: progression-free survival (PFS) The secondary endpoint:, overall survival (OS) and safety. Material and Methods The study enrolled 10 patients with advanced pancreatic adenocarcinoma from Dec. 2015 to Apr. 2018. In the first week, all the patients were treated with Apatinib 500mg daily 。 At the same time, treatment plans of SBRT were finished. From the second week , Apatinib was taken 500mg daily and SBRT were goning concomitantly. SBRT regimen was 50Gy/20F/4W. Same dosage of Apatinib was continued alone after SBRT to disease progression, death, or intolerable toxicity.

Results All patients were followed up for the tumor response evaluation. The median progression-free survival (PFS) was 4.5 months (95% CI, 3.47 to 5.53). The median overall survival (OS) was 7.5 months (95% CI, 5.95 to 9.05). Safety and Tolerability Hypertension is one of the most frequent adverse events, which appeared in 3 of 10 pts. There also were some other AEs, Hand-food syndrome 2, proteinuria 1, diarrhea 1 , fatigue 1, oral mucositis 1 and thrombocytopenia 1. AEs could be better controlled and no treatment-related hemorrhage occurred.

AE(%)

All Grade3/4

Hypertension 3 0 Hand-food syndrome 2 0 proteinuria 1 0 diarrhea 1 0 fatigue 1 0 oral mucositis 1 0 thrombocytopenia 1 0

Conclusion Our Results indicates that Apatinib combined with SBRT exhibites safety and efficacy to advanced pancreatic adenocarcinoma. More patients should be enrolled and observed EP-1400 Comparing Treatment Plans for Proximal and Middle/Distal Stomach Cancer: IMRT, VMAT, and Tomotherapy Y. Chen 1 , J. Lin 1,2 , S. Huang 1 , Y. Chou 3 , M. Li 1 , J. Tsai 1,2 1 Shuang Ho Hospital- Taipei Medical University, Department of Radiation Oncology, New Taipei City, Taiwan ; 2 School of Medicine- College of Medicine- Taipei Medical University, Department of Radiology, Taipei, Taiwan ; 3 National Defense Medical Center, School of Public Health, Taipei, Taiwan Purpose or Objective Adjuvant chemoradiotherapy is viewed as a definitive treatment after resection of stomach cancer (SC). To protect normal tissue, several highly conformal radiotherapy modalities evolved. Therefore , we aimed to compare dosimetric parameters of helical tomotherapy (TOMO), volumetric-modulated arc therapy (VMAT), and intensity-modulated radiotherapy (IMRT) in the adjuvant treatment of SC in different locations. Material and Methods This retrospective study was conducted from January 2013 to May 2017 and included 11 patients with gastric cancer receiving adjuvant chemoradiotherapy after total