ESTRO 38 Abstract book

S740 ESTRO 38

Pathology, Leeds, United Kingdom ; 8 Odense University Hospital, Laboratory of Radiation Physics, Odense, Denmark ; 9 Vejle Hospital- University of Southern Denmark, Department of Oncology, Vejle, Denmark ; 10 Aarhus University Hospital, Department of Medical Physics, Aarhus, Denmark ; 11 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark ; 12 Vejle Hospital- University of Southern Denmark, Department of Medical Physics, Vejle, Denmark Purpose or Objective The standard treatment of locally advanced non-small cell lung cancer (LA-NSCLC) has changed with the PACIFIC trial, stating that the addition of 1-year adjuvant immune checkpoint inhibitor therapy after completed concomitant chemoradiotherapy increases the 2-year survival rate compared to placebo. Inclusion criteria were a WHO performance status (PS) of 0-1 and no sign of progression. Adjuvant therapy should start within 42 days of completed chemoradiotherapy. The aim of this analysis was to determine the fraction of patients with LA-NSCLC that have PS 0-1 within six weeks after completion of concomitant chemoradiotherapy and would hence be candidates for adjuvant immune checkpoint inhibitor therapy. Material and Methods We are currently recruiting patients with LA-NSCLC in a national multicenter randomized phase III isotoxic dose escalation trial. In the study the control arm receives 66 Gy in 33 fractions concomitantly with cis- or carboplatin every third week and fixed dose vinorelbine 50 mg three times weekly. The concomitant chemoradiotherapy is proceeded by a single series of induction platinum-based combination chemotherapy. Radiotherapy is delivered with intensity modulated or volumetric arc modulated therapy. Daily image guidance with conebeam CT and treatment adaptation guidelines are used. The trial inclusion criteria are cytology or histology proven LA-NSCLC and PS 0-1. Diagnostic procedures include FDG- PET/CT and endobronchial ultrasound (EBUS) with aspiration cytology from central mediastinal nodes. We are investigating the possibility of an amendment to allow for adjuvant immune checkpoint inhibitor therapy to enable continuous inclusion in the study. Thus, an unplanned interim analysis was performed within the trial, analyzing only baseline characteristics and PS at the first clinical follow-up six weeks post radiotherapy. Results Patients were included from January 2015 and forward. Data lock for the interim analysis was September 1 st , 2018. 124 patients had completed their treatment and attended their first clinical follow-up. Clinical report form was filled out for 109 patients; PS data were missing for ten patients, leaving 99 for analysis. Patient characteristics are shown in Table 1. PS at start and six weeks after end of radiotherapy are shown in Figure 1. No patients were in PS3 or 4 after radiotherapy. Conclusion The majority of patients (85%) with LA-NSCLC, who were staged with EBUS and PET/CT and received state-of-the art concomitant chemoradiotherapy in a randomized dose escalation trial, remained in PS 0-1 after finished radiotherapy and were thus candidates for adjuvant immune checkpoint inhibitor therapy.

EP-1353 Lung cancer extrecerebral oligometastases/oligoprogression stereotactic irradiation M. Kissel 1 , I. Martel-Lafay 2 , J. Lequesne 3 , J. Faivre 4 , C. Le Péchoux 5 , D. Stefan 1 , V. Barraux 1 , C. Loiseau 1 , J. Grellard 3 , S. Danhier 1 , D. Lerouge 1 , C. Chouaid 6 , R. Gervais 7 , J. Thariat 1 1 Centre François Baclesse, Radiotherapy, Caen, France ; 2 Centre Léon Bérard, Radiotherapy, Lyon, France ; 3 Centre François Baclesse, Clinical research, Caen, France ; 4 Institut de Cancérologie de Lorraine, Radiotherapy, Nancy, France ; 5 Institut Gustave Roussy, Radiotherapy, Villejuif, France ; 6 Centre Hospitalier Intercommunal de Créteil, Pneumology, Créteil, France ; 7 Centre François Baclesse, Pneumology, Caen, France Purpose or Objective While stereotactic irradiation (SBRT) of cerebral metastases is standard in oligometastatic lung cancer, the clinical benefit of SBRT in extracranial metastases depending on metastatic burden and aggressiveness awaits evidence. The aim was to assess feasibility and efficacy of a radical approach on all extracerebral metastatic sites among lung cancer patients with an “oligo” disease. Material and Methods This retrospective multicentric study in four French cancer centers included patients treated with SBRT on all their extracerebral metastatic sites corresponding to the following settings : extracerebral oligometastatic (one to five lesions at diagnosis), oligorecurrent (metastatic relapse with one to five metastases), oligoprogressive (1- 5 progressive lesions with all other lesions controlled by systemic treatment) or oligopersistent (consolidative