ESTRO 38 Abstract book

S419 ESTRO 38

patients per hospital in the survival of patients with locally advanced ESCC submitted to chemoradiotherapy plus surgery (S+RCT) or definitive chemoradiotherapy (RCT). Material and Methods We used the Fundação Oncocentro de São Paulo (FOSP) database to identify 18 years old or older patients who received a diagnosis of stage II, or III (non-T4) ESCC between 2000 and 2013 (1347 patients and 64 hospitals). Treatments initiated 365 days after diagnosis, without T and N definition and with early mortality (until 60 days of diagnosis) were excluded. Descriptive variables were first accessed with chi-square test after categorizing hospitals as high (HH) or low volume (LH), 100 surgeries per year was used to divide the groups. Overall survival (OS) was compared with a log-rank test and with a Cox proportional hazards method, adjusting for all variables, then we tested the possible interaction between treatment type and volume facility. Results 66% of patients were treated in HH hospitals, and 23% were treated with S+CRT without significative difference between facility’s surgery volume and treatment performed (p=0,96). There were more stage III ESCC treated in LH (46,1 vs 34,3% p<0,01), more treatment initiated after 60 days of diagnosis in HH (61,0 vs 38,3% p<0,01) and no significative age difference in volume facilities groups (p=0,48). Median OS in months was 14,7 in HH/CRT, 24,9 in HH/S+CRT, 13,1 in LH/CRT and 15,1 in LH/S+CRT with positive association in log-rank test (p rank <0,001).

Conclusion Although S+RCT is the gold standard for ESCC treatment, our data demonstrate different outcomes according to the facility’s treatment volume. Suggesting that esophagectomy should be performed only in more experienced centers. PO-0807 Heterogeneous FDG-guided dose escalation in definitive oesophageal radiotherapy: a feasibility study H.R. Mortensen 1 , M. Nordsmark 2 , D.S. Møller 3 , S.N. Risum 4 , E. Holtved 5 , M. Nielsen 6 , B. Weber 7 , M. Josipovic 8 , L. Hoffmann 9 1 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark ; 2 Aarhus University Hospital, Department of Oncology, Aarhus-, Denmark ; 3 Aarhus Universityhospital, Department of Medical Physics, Aarhus, Denmark ; 4 Rigshospitalet Copenhagen University Hospital-, Department of Oncology, Copenhagen, Denmark ; 5 Odense University Hospital, Department of Oncology, Odense, Denmark ; 6 Odense University Hospital-, Laboratory of Radiation Physics, Odense, Denmark ; 7 Aarhus University Hospital-, Department of Oncology, Aarhus, Denmark ; 8 Rigshospitalet Copenhagen University Hospital-, Department of Oncology-, copenhagen, Denmark ; 9 Aarhus University Hospital-, Department of Medical Physics-, Aarhus, Denmark Purpose or Objective Patients with localised esophageal and gastroesophageal junction (GEJ) cancer are offered definite chemo- radiotherapy if considered non-resectable or medically inoperable. Despite treatment with curative intent a median survival of less than 20 months and a 5-year survival of 15-25% were found in clinical trials. Survival is affected by several factors, including lack of locoregional control with failures located in the treated target volumes.

In Cox analysis, female sex (HR 0,76 p<0,01) and treatment in HH (HR 0,82 p<0,01) were associated with better overall survival. Patients treated with RCT had worst OS (HR 1,38 p<0,001). After performing sensitivity analysis for treatment type and facility’s surgery volume, we note a significative worst OS in those treated with CRT in HH (HR: 1,56; IC: 1,28-1,89) and no difference in that treated with CRT in LH (HR: 1,23; IC: 0,88-1,43), ( p interaction =0,035).