ESTRO 38 Abstract book

S418 ESTRO 38

(22.4%), irresectability in 14 (12.1%), patients’ own decision in 17 (14.7%; 10 of them had a cCR) and death during NT in 9 (7.8%) patients (Table 1). Patients refusing surgery had an improved median OS compared to those in whom esophagectomy was cancelled for other reasons (30.1 vs 13.8 months; p<0.0001) (Figure 1). In the second time period, irresectability decreased (17.4% vs 5.7%; p=0.0279). Median OS was not different over time (9.2 vs 12.6 months; p=0.897). Irresectability (p=0.031), patients’ refusal (p=0.015) and poor general condition (p<0.001) were more frequent as reasons for cancellation in SCC patients. Median OS was 12.9 and 9.9 months for patients with an AC and a SCC (p=0.485), respectively. Median OS of patients in the surgery and non-surgery group was 36.5 and 10.8 months (p<0.0001).

Conclusion Re-irradiation with SBRT can provide effective analgesia and disease control with tolerable toxicity after prior SBRT for in-field recurrence, which is feasible for local relapsed pancreatic cancer. But it should be employed in highly selected patients with distant metastasis. PO-0805 Analysis of esophageal cancer patients treated with neoadjuvant therapy who never made it to surgery M. Thomas 1,2 , L. Depypere 3,4 , J. Moons 4 , W. Coosemans 3,4 , T. Lerut 3,4 , H. Prenen 5 , K. Haustermans 1,2 , H. Van Veer 3,4 , P. Nafteux 3,4 1 KU Leuven – University of Leuven, Department of Oncology – Laboratory Experimental Radiotherapy, B- 3000 Leuven, Belgium ; 2 UZ Leuven – University Hospitals Leuven, Department of Radiation Oncology, B-3000 Leuven, Belgium ; 3 KU Leuven – University of Leuven, Department of Chrometa, B-3000 Leuven, Belgium ; 4 UZ Leuven – University Hospitals Leuven, Department of Thoracic Surgery, B-3000 Leuven, Belgium ; 5 UZA – University Hospital Antwerp, Department of Oncology, B-2000 Antwerp, Belgium Purpose or Objective Neoadjuvant treatment (NT) followed by esophagectomy is standard practice in patients with locally advanced resectable esophageal cancer (EC). However, not all patients who start NT will undergo esophageal resection. The aim of this study was to evaluate the group of patients, scheduled for NT followed by esophagectomy, who never made it to surgery. Material and Methods We performed a retrospective institutional analysis of patients treated for locally advanced EC with NT (2002- 2015), who did not undergo esophagectomy. Tumor (histology, cTNM, tumor location), patient (age, gender) and treatment related (NT regimen) characteristics were collected. The reason for cancellation of surgery and the proportion of patients with a clinical complete response (cCR) were reviewed. Subanalysis was performed according to the time period (2002-2010 vs 2011-2015) and histology (adenocarcinoma (AC) vs squamous cell carcinoma (SCC)). Median overall survival (OS) was calculated for the entire patient cohort and according to the two time frames and histology. Results In 116 of 681 patients (17.0%), surgery was not performed after NT. NT treatment included chemoradiotherapy in 95 (81.9%) and chemotherapy alone in 21 (18.1%) patients. The median age of the patients not undergoing surgery was 66 years (IQR 60-70). The predominant clinical tumor stage was cT3 (75.9%) and most patients were clinically node positive (89.7%). A cCR was obtained in 23 patients (19.8%). Reasons for cancellation of surgery were disease progression in 50 (43.1%), poor general condition in 26

Conclusion One in six patients starting NT for EC never made it to surgery. Over time, irresectability as reason decreased. As a result, medical reasons became more important, indicating the paramount importance for upfront testing of medical operability. Cancellation of surgery was significantly more common in SCC patients. Reasons were medical inoperability and patients’ own decision, besides a higher number of irresectable tumors. Patients who refused esophagectomy, often because of cCR, had a significant survival benefit compared to those who did not undergo esophagectomy because of other reasons. PO-0806 Impact of Hospital Volume and Trimodality in Survival Outcomes for Esophageal Cancer M. Bringel oliveira duarte 1 , J. Barreto Campello Carvalheira 2 , E. Baldon Pereira 1 1 Hospital de Clínicas - Universidade Estadual de Campinas, Radiation Oncology, Campinas, Brazil ; 2 Hospital de Clínicas - Universidade Estadual de Campinas, Clinical Oncology, Campinas, Brazil Purpose or Objective Hospitals with a low volume of surgeries for esophageal cancer usually present a proportionally higher rate of complications for this procedure. However, it is unclear whether limited access to hospitals with a high volume of surgeries could influence the therapeutic plan for locally advanced esophageal squamous cell carcinoma (ESCC) in underdeveloped countries. Thus, in this population-based study, we assessed the influence of the number of treated