ESTRO 2020 Abstract Book

S167 ESTRO 2020

fatigue may be mediated by each of these factors needs further study.

OC-0318 Neurotoxicity of early prophylactic cranial radiation and hippocampal avoidance in SCLC (SAKK 15/12) H. Vees 1 , F. Caparrotti 2 , E.I. Eboulet 3 , A. Xyrafas 3 , A. Fuhrer 4 , U. Meier 5 , M. Mark 6 , O. Elicin 7 , D.M. Aebersold 7 , D.R. Zwahlen 6 , T. Finazzi 8 , A. Said Allal 9 , P.M. Putora 10 , F. Martucci 11 , C. Biaggi Rudolf 4 , K. Ribi 12 1 Hirslanden Klinik Zürich, Radiotherapie, Zürich, Switzerland ; 2 University Hospital of Geneva, Radiation Oncology, Geneva, Switzerland ; 3 SAKK Coordinating Center, Informatics, Bern, Switzerland ; 4 SAKK Coordinating Center, Coordinating Center, Bern, Switzerland ; 5 Cantonal Hospital of Winterthur, Radiation Oncology, Winterthur, Switzerland ; 6 Cantonal Hospital of Graubünden, Departement of Hematology/Oncology, Chur, Switzerland ; 7 Inselspital- Bern University Hospital, Department of Radiation Oncology, Bern, Switzerland ; 8 University Hospital of Basel, Clinic of Radiotherapy and Radiation Oncology, Basel, Switzerland ; 9 Cantonal Hospital of Fribourg - HFR, Radiation Oncology, Fribourg, Switzerland ; 10 Cantonal Hospital of St. Gallen, Radiation Oncology, Sst. Gallen, Switzerland ; 11 Oncology Institute of Southern Switzerland, Radiation Oncology, Bellinzona, Switzerland ; 12 SAKK Coordinating Center, Quality of Life Office and International Breast Cancer Study Group IBCSG Coordinating Center, Bern, Switzerland Purpose or Objective To evaluate neurocognitive function (NCF) and clinical outcomes after early hippocampal avoidance (HA) prophylactic cranial irradiation (PCI) in limited disease (LD) small-cell lung cancer (SCLC) in a multicenter phase In a phase II trial, patients with LD SCLC received HA-PCI of 25 Gy in 10 fractions concomitant to the 2nd cycle of chemotherapy (CHT) and thoracic radiotherapy. All patients underwent objective NCF testing at baseline, 6 weeks, 6 and 12 months after HA-PCI. NCF tests included Hopkins Verbal Learning Test Revised (HVLT-R), Controlled Oral Word Association (COWAT), and Trail Making Tests (TMT) A and B. The primary endpoint was NCF decline at 6 months after HA-PCI. We assumed a rate of ≤ 30% of patients with no NCF decline as unpromising. Secondary endpoints included brain metastases free survival (BMFS), overall survival (OS), and safety of the concomitant treatment. Results Among the 44 patients enrolled in the trial, 38 had evaluable NCF assessment at 6 months after HA-PCI. The rate of evaluable patients showing no NCF decline at 6 and 12 months was 34.2% (90% CI: 21.6 - 48.8%) and 48.5% (95% CI: 30.8 - 66.5%), respectively (Figure 1). Median follow- up was 13.2 months (95% CI: 12.6 - 14.1). At 12 months, the rate of BMFS was 84.2% (95% CI: 68.1 - 92.8%), and of OS was 87.7% (95% CI: 73.0 - 94.7%). Four patients died due to SCLC, 1 due to respiratory failure, 1 due to hemorrhage, and 1 for unknown reason. The most frequently reported grade ≥ 3 acute adverse events were anemia (21.4%), febrile neutropenia (19.1%) and fatigue (14.3%). II trial (SAKK 15/12). Material and Methods

Conclusion The rate of patients showing no NCF decline 6 and 12 months after early HA-PCI concomitant to CHT does not appear to be better, but rather similar to that observed in patients receiving sequential PCI without HA. 1 Early HA-PCI in LD SCLC is feasible, with observation of promising BMFS and OS. Reference: 1. Wolfson AH, Bae K, Komaki R, et al. Primary Analysis of a Phase II Randomized Trial Radiation Therapy Oncology Group (RTOG) 0212: Impact of Different Total Doses and Schedules of Prophylactic Cranial Irradiation on Chronic Neurotoxicity and Quality of Life for Patients With Limited-Disease Small-Cell Lung Cancer. Int J Radiat Oncol Biol Phys. 2011;81(1):77-84. OC-0319 Validation of a companion diagnostic biomarker for prospective use in prostate radiotherapy trials N. Thiruthaneeswaran 1,2 , B.A.S. Bibby 1 , R. Pereira 3 , E. More 1 , R.G. Bristow 3,4 , A. Choudhury 1 , C. West 1 1 University of Manchester, Translational Radiobiology, Manchester, United Kingdom ; 2 University of Sydney, Sydney Medical School, Sydney, Australia ; 3 University of Manchester, Translational Oncogenomics, Manchester, United Kingdom ; 4 Manchester Cancer Research Centre, The Oglesby Cancer Research Building, Manchester, United Kingdom Purpose or Objective A 28-gene hypoxia-associated signature (HS) was derived for prostate cancer. The signature was validated for prognostic significance in eight prostatectomy, a definitive radiotherapy cohort and a salvage radiotherapy cohort. Biomarker validation using scant or minimal formalin-fixed paraffin-embedded (FFPE) tissue from diagnostic biopsies is a challenge due to nucleic acid degradation and low tissue volume. The aim of this study was to technically validate the robustness of the signature for reproducibility, reliability and intratumour heterogeneity. Material and Methods Diagnostic FFPE needle core (NC) biopsies from high-risk prostate cancer patients treated with different radiotherapy regimens were collected (n=663). Intratumour heterogeneity was assessed in 40 patient samples with multiple tumour FFPE NC blocks. Correlation was assessed in matched needle core to macrodissected prostatectomy samples in 12 patients. To assess downstream usability of extracted retrospective RNA three Proffered Papers: Proffered papers 15: Radiation response biomarkers