ESTRO 2020 Abstract Book

S223 ESTRO 2020

5 Kliniken Maria Hilf, Department of Radiation Oncology, Mönchengladbach, Germany ; 6 Helios University Hospital Wuppertal, Department of Nuclear Medicine, Wuppertal- , Germany ; 7 Marienhospital Stuttgart, Department of Nuclear Medicine, Stuttgart, Germany ; 8 Klinikum Mutterhaus der Boromäerinnen, Department of Radiation Magdeburg, Germany ; 10 Charité University Hospital-, Department of Radiation Oncology, Berlin, Germany ; 11 University Hospital Mainz-, Department of Radiation Oncology, Mainz, Germany ; 12 Medical University of Vienna, Department of Radiotherapy, Vienna, Germany ; 13 University Hospital Mainz, Department of Nuclear Medicine, Mainz, Germany ; 14 Helios Kliniken Schwerin, Department of Nuclear Medicine, Schwerin, Germany ; 15 University of Freiburg, Institute of Medical Biometry and Statistics IMBI, Freiburg, Germany ; 16 University of Mainz, Institute of Medical Biostatistics- Epidemiology and Informatics IMBEI-, Mainz, Germany Purpose or Objective Concurrent chemotherapy is the standard of care for locally advanced non-small cell lung cancer (NSCLC) treated with definitive radiotherapy. The optimal chemotherapy protocol for use with concurrent therapy is not known. In this analysis we evaluated the role of different chemotherapy protocols in patients treated in the phase III PET Plan trial (ARO 2009-09; NCT00697333). Material and Methods The prospective randomized controlled phase-III PET-Plan trial was conducted in 24 centers. Patients with inoperable locally advanced NSCLC suitable for radio-chemotherapy were randomized at a 1:1 ratio concerning the target volume (TV) definition and received quality-assured isotoxically dose-escalated RT (60–74 Gy, 2 Gy per fraction) was applied to the respective TVs. Concurrent platinum-based chemotherapy was mostly conducted according to Vokes et al.(Vokes, II et al. 2002), using cisplatin 80mg/m² (day 1 and 22) and vinorelbin 15mg/m² (day1+8 and 22+29) (protocol 1, P1) or cisplatin 20mg/m² (day1-5 and 29-33) and vinorelbin 12.5 mg/m² (day 1,8,15 and 29,36,43) (protocol 1, P2) or carboplatin AUC1 (day1- 5 and 29-33) and vinorelbin 12.5 mg/m² (day 1,8,15 and 29,36,43) (protocol 1, P3) according to Semrau et al.(Semrau, Klautke et al. 2008), at the discretion of the treating physician. Results Between 05/2009 and 11/2016, 205 patients were randomized and 172 patients in the per-protocol analysis (A: n=84, B: n=88). 30 patients were treated according to P1, 92 according to P2 and 28 according to P3. One patient did not receive any treatment in Arm A (1%) and 21 patients received different treatments. In the PP analysis of 79% in arm A and 82% in arm B received the 1st cycle per protocol (pp) and 73% (Arm A) and 72% (Arm B) received the 2nd cycle pp but there was no statistical significant difference in regards of overall survival (OS) and progression free survival (PFS). Causes of deviation were mostly renal or hematologic toxicity. All 3 protocols were well tolerated. Patients in P1 (17%) und P2 (15%) developed more grade 3 leucopenia than P3 (4%) but less grade 3 renal toxicities 0% (P1,2) vs 4%(P3). Only patients in P1 developed grade 4 hematologic toxicities (7% leuco- , 3% thrombocytopenia and 3% anemia ).Patents treated with P1 or P2 had a better survival as opposed to P3 (p=0.008 and p=0.009 respectively) but there was no difference between P1 and P2 (p=0.6). Furthermore there was no difference observed concerning PFS between the Oncology, Trier, Germany ; 9 University Hospital Magdeburg, Department of Radiation Oncology,

Finally, sCTs were generated starting from the auto- segmented bones and OARs in the treatment planning system (Monaco, Elekta). A bulk electron density was assigned to each volume. Electron densities were averaged over 19 patients CTs who underwent to prostate radiotherapy (Fig.1). Three 10MV photon VMAT prostate plans were optimized for three patients on planning CT and recalculated on the corresponding sCT. Dosimetric differences to planning CT were evaluated by using quantitative methods such as dose-volume histogram (DVH) and 2D local gamma analysis.

Results The mean deviation of DVH-parameters for PTV and OARs for the three patients were less than 1.5%. 2D local gamma analysis, using an acceptance criterion of 2% and 2mm, provided average pass rates of 99.9% for the axial and coronal planes and 100% in the sagittal plane. Under the strict passing criteria of 1% and 1 mm, the average pass rate was 98.6%, 96.7% and 95.9% for the axial, coronal and sagittal planes, respectively.

Conclusion This study demonstrates that MRI-only planning for prostate patients is feasible using our proposed MRI optimized sequence and hybrid bulk - multi-atlas method. In particular sCT-based treatment plans provide dosimetric and gamma analysis values in close agreement to original CT-based. This method provides also quite nice contours with few corrections before planning: quantitative analysis will be finalized with an expanded cohort of patients to increase the efficiency of the atlas. PD-0413 The role of different chemotherapy protocols for concurrent CRT in locally advanced NSCLC E. Gkika 1 , S. Tanja 1 , K. Stephanie 2 , A. Schaefer-Schuler 3 , M. Mix 4 , A. Küsters 5 , M. Tosch 6 , S.M. Eschmann 7 , Y. Bultel 8 , P. Hass 9 , J. Fleckenstein 2 , A. Thieme 10 , M. Stockinger 11 , K. Dieckmann 12 , M. Miederer 13 , G. Holl 14 , C. Rischke 1 , S. Adebahr 1 , S. Lenz 15 , C. Broichhagen 15 , H. Binder 15 , J. König 16 , A. Grosu 1 , U. Nestle 1,5 1 Uniklinik Freiburg, Radiation Oncology, Freiburg, Germany ; 2 Saarland University Hospital, Department of Radiation Oncology, Homburg/Saar, Germany ; 3 Saarland University Hospital, Department of Nuclear Medicine, Homburg/Saar, Germany ; 4 Uniklinik Freiburg, Department of Nuclear Medicine, Freiburg, Germany ; Poster discussion: CL: Lung