ESTRO 2020 Abstract book

S614 ESTRO 2020

Between June 2016 and February 2019, 54 patients with BR or UR pancreatic adenocarcinoma who underwent gemcitabine plus S-1 with concurrent radiotherapy (total dose, 50.4Gy/28fr) were retrospectively studied. The median age was 69 years and 18 patients (33%) were female. Twenty-four patients (44%) had UR pancreatic adenocarcinoma. Pretreatment CA 19-9 (pre CA19-9) and CA19-9 a month after CRT (post CA19-9) were investigated. Univariate and multivariate analyses were performed to evaluate the prognostic value of pre CA19-9, post CA19-9, age, sex, tumor location, stage, resectability (BR vs. UR), and neutrophil-to-lymphocyte ratio for prediction of overall survival (OS) and progression-free survival (PFS). Results The median follow-up time was 15 months. Twenty-four patients (44%) received surgery after CRT. Thirty-five patients (63%) experienced disease recurrence or death (disease recurrence; 32 patients, 59%, death; 24 patients, 44%). Recurrence within 6 months after CRT occurred in 19 patients (35%). The median pre CA 19-9 and post CA19-9 were 330 U/mL and 44 U/mL, respectively. Univariate analysis showed poor prognosis with higher pre CA19-9 (OS, p=0.031), higher post CA19-9 (OS; p=0.013, PFS; p=0.009), and UR (PFS, p=0.025). Multivariate analysis revealed that post CA19-9 was an independent prognostic factor for OS (Hazard ratio [95% CI], 2.762 [1.187-6.470]; p=0.018) and PFS (Hazard ratio [95% CI], 2.364 [1.173-4.761]; p=0.016), and resectability (BR vs. UR) was for PFS (Hazard ratio [95% CI], 2.063 [1.042-4.083]; p=0.038). Post CA19-9 was higher in patients who had early recurrence compared with others (4520 (0.2-53259) vs 136 (0.1-843) U/mL, p <0.001). Six patients with high post CA19-9 (>1000 U/mL) had early recurrence.

Conclusion SBRT is a safe procedure and provides high LC rates in HCC patients, in particular if a dose regimen delivering a BED ≥120 Gy 10 is applied. Despite excellent local control, out- of-field progression remains of concern. SBRT following prior surgical resection is correlated to improved survival. PO-1070 Effect of surgery in locally advanced esophageal cancer after chemoradiotherapy I. Alda Bravo 1 , S. Fernandez Alonso 1 , M. Alarza Cano 1 , M.Á. Pérez-Escutia 1 , R. D'Ambrossi 1 , M.C. Peña 1 , M. Colmenero 1 , J.F. Pérez-Regadera 1 1 Hospital universitario 12 de Octubre, Servicio de Oncología Radioterápica, Madrid, Spain Purpose or Objective Neoadjuvant chemoradiotherapy followed by surgery is the standard treatment for locally advanced esophageal cancer (LAEC). The purpose of this study was to determine whether the addition of surgery improves survival. Material and Methods We retrospectively analyzed 75 LAEC patients treated between 2003 and 2019 in a department of radiation oncology. Histology was 75% squamous and 25% adenocarcinoma. Patients received 3D/VMAT radiotherapy to a dose of 45-60Gy. Patients underwent restaging using CT and Endoscopy at week 4-8, and, if deemed fit/suitable, surgery at week 8-10. Survival was estimated using Kaplan-Meier method and Log-Rank test. Results Median age was 69y, and 86% were males. 53% of tumors arose form the middle/upper third. 50% had T3/T4 tumors and 55% had positive nodes. Patients received: definitive chemo-RT (62%) or neoadjuvant chemoRT followed by surgery (38%). Pathological complete response (pCR) was achieved in 30% and R0 resection in 90%. After definitive chemoRT, 32% and 50% had partial or complete response. Median follow up 17 months, median OS and DFS were 21 and 17 months respectively. 2yOS was 41% after definitive chemoRT and 56% after surgery. pCR/no-pCR 2yDFS was 72%/32%. The addition of surgery for squamous or upper third tumors, did not improve survival, but was associated with improved DFS for adenocarcinoma or lower third tumors (p=0.001 and p=0.028, respectively). Conclusion Squamous or upper/middle third patients do not benefit from surgery, making them candidates for observation especially after complete response. Surgery improves survival in adenocarcinomas and lower third tumors. PO-1071 Prognostic value of CA19-9 in patients with pancreatic adenocarcinoma after chemoradiotherapy Y. Nampei 1 , Y. Toyomasu 1 , S. Ochiai 2 , T. Mase 1 , Y. Watanabe 1 , T. Kawamura 1 , A. Takada 1 , Y. Yamashita 3 , N. Ii 4 , H. Sakuma 1 , Y. Nomoto 1 1 Mie University School of Medicine, Radiology, Tsu, Japan ; 2 Saiseikai Matsusaka General Hospital, Radiation Oncology, Matsusaka, Japan ; 3 Matsusaka Central Hospital, Radiation Oncology, Matsusaka, Japan ; 4 Ise red cross hospital, Radiation Oncology, Ise, Japan Purpose or Objective The study objective was clarifying the role of CA19-9 in determining prognosis for patients with borderline resectable (BR) or locally advanced unresectable (UR) pancreatic adenocarcinoma receiving chemoradiotherapy (CRT). Material and Methods