ESTRO 38 Abstract book

S415 ESTRO 38

months vs. 13.8 months, P<0.001; LC: 10.5 months vs. 15.0 months, P<0.001). Conclusion BED escalation >70Gy may provide survival benefits and better local control in patients with pancreatic cancer but require further validation in prospective studies. PO-0801 Esophageal Cancer: One Organ, Two Histologies, One Treatment Strategy: Why? M. Lamande 1,2 , L. Grandjean 1 , E. Gonne 3 , D. Van Daele 4 , J. Collignon 3 , M. Polus 4 , C. Loly 4 , J. Vanderick 1 , P. Coucke 1 , P. Martinive 1,2 1 C.H.U. - Sart Tilman, Department of Radiotherapy, Liège, Belgium ; 2 Institut Jules Bordet, Department of Radiotherapy, Brussels, Belgium ; 3 C.H.U. - Sart Tilman, Department of Medical Oncology, Liège, Belgium ; 4 C.H.U. - Sart Tilman, Department of Gastroenterology and Digestive Oncology, Liège, Belgium Purpose or Objective Neoadjuvant radiochemotherapy (NRTC) is recommended for Adenocarcinoma (ADK) and Squamous Cell Carcinoma (SCC) of the esophagus for patients with good performance status and tumor located in the lower third of the esophagus. While often treated as a sole and unique entity, esophageal cancer could be viewed as two different pathologies based on tumor histology, pathogenicity and patient related co-morbidities. The aim of this study was to assess the Overall Survival (OS), median OS (mOS), Local and Distant Recurrences (LR/DR) in regard of tumor histology. Material and Methods We retrospectively reviewed a cohort of patients with histological proven SCC or ADK esophageal cancer who received either definitive RTC or NRTC from 01/01/08 to 10/15/16. For definitive RTC patients received 50,4Gy in 28 fractions concomitantly with Cisplatin and 5FU or Carboplatin and Taxol. For NRTC they received 45Gy in 25 fractions with Carboplatin and Taxol. Patients who were not electable for NRTC due to co-morbidities, tumor stage or tumor location were treated by RCT and salvage We identified 112 patients, 74 SCC and 38 ADK. NRTC was administrated to 9 SCC and 24 ADK, all the others received RTC. With a median follow up of 40 months, the 3 and 5y OS and mOS for all the cohort are for RTC 33%, 25,4% and 21,1 mo and for NRTC 38,5% 38,5% and 24,3mo, respectively (p=ns). Among 74 SCC (Ratio M/F=2), 85,1% were former smokers and 64% were still active and 71,6% had alcoholic habits at diagnosis. The 3 and 5y OS for RTC are 38% and 32% with 21,8mo mOS. For NRTC the 3y OS is 22,4% and 22,4mo mOS. Recurrences occurred in 40 % patients (LR alone 11%, LR and DR 5%, DR 24%). Most recurrences occurred (74%) during the first year after treatment and 70% of those patients died within the year of the relapse. Among 38 ADK (Ratio M/F=8,5), 65,8% were former and 47,4% were still active smokers and 26,3 % had alcoholic habits at diagnosis. Most of the patients (63%) were treated with NRCT. Recurrences occurred in 50 % patients (LR alone 5%, LR and DR 5%, DR alone 39%) and 58% of these relapses occurred within the first year. The mOS of RTC was 8,25 months without any survivors at 3 years. NRCT approach showed a mOS of 24,3 mo and 3 years OS of 40 %. Due to limited number of patients the 5 years OS is not reliable. More details are featured in Table surgery. Results

Conclusion Our study revealed that long-term survival is still achievable for patients with cT4b N+ EC. Patients with younger age, higher BMI, and cN1 disease tended to have better OS while salvage esophagectomy may further improve the outcomes. PO-0800 Radiation dose escalation in pancreatic cancer: a propensity-score matching study X. Zhu 1 , C. Yangsen 1 , Z. Xianzhi 1 , S. Yuxin 1 , J. Xiaoping 1 , Q. Shuiwang 1 , C. Fei 1 , J. Zhen 1 , F. Fang 1 , G. Lei 1 , Z. Huojun 1 1 Changhai Hospital, Radiation Oncology, Shanghai, China Purpose or Objective For patients with locally advanced pancreatic cancer, standard therapy consists of different combinations of chemotherapy and radiotherapy. Additionally, chemoradiotherapy may be the alternative option for those with resectable or borderline resectable but medically inoperable pancreatic cancer though there was no consensus about the optimal therapy. However, fewer studies have evaluated the association of radiation dose and survival or local control. Therefore, the aim of the study was to investigate the role of dose escalation in non- operable pancreatic cancer. Material and Methods Consecutive patients with resectable or borderline resectable but medically inoperable due to comorbidities and locally advanced pancreatic cancer receiving SBRT and chemotherapy were included. Patient demographic and treatment information were stratified by a BED 10 of 60 to 70Gy versus a BED 10 >70Gy. Factors predictive of overall survival (OS), progression free survival (PFS) and local control (LC) were identified by multivariate analysis. OS, PFS and LC were further compared using propensity score matching. Results Four hundred and thirty-three patients were included; 330 received 60 to 70Gy and 107 received doses >70Gy. Univariate analysis showed that tumor stage and CA19-9 response correlated with OS and PFS, while tumor stage, CA19-9 response and ECOG was associated with LC. After multivariate analysis, both tumor stage and CA19-9 response were predictive of OS, PFS and LC (P<0.001 for all analyses). Therefore, these two factors were used to develop matched cohorts. One hundred and seven patients in each group were included after propensity-score matching. Patients with a BED 10 >70Gy had a superior OS, PFS and LC compared with those with a BED 10 of 60 to 70Gy (OS: 13.7 months vs. 17.6 months, P<0.001; PFS: 9.4