ESTRO 2023 - Abstract Book

S483

Sunday 14 May 2023

ESTRO 2023

Proffered Papers: Gynaecology

OC-0601 Early toxicity and quality of life after molecular-based adjuvant treatment in the PORTEC-4a trial A. van den Heerik 1 , C. Post 1 , L. Lutgens 2 , D. Haverkort 3 , S. Kommoss 4 , F. Koppe 5 , M. Nowee 6 , H. Westerveld 7 , M. de Jong 8 , D. Cibula 9 , J. Cnossen 10 , J.W. Mens 11 , C. Chargari 12 , S. Bijmolt 13 , C. Gillham 14 , T. Stam 15 , I. Jurgenliemk-Schulz 16 , K. Vandecasteele 17 , K. Verhoeven-Adema 18 , R. Nout 1,11 , H. Putter 19 , V. Smit 20 , N. Horeweg 1 , T. Bosse 20 , C. Creutzberg 1 1 Leiden University Medical Center, Radiation Oncology, Leiden, The Netherlands; 2 Maastricht Radiation Oncology Clinic, Radiation Oncology, Maastricht, The Netherlands; 3 Radiotherapy Group, Radiation Oncology, Arnhem, The Netherlands; 4 University of Tübingen, Women’s Health, Tübingen, Germany; 5 Institute Verbeeten, Radiation Oncology, Tilburg, The Netherlands; 6 Netherlands Cancer Institute, Radiation Oncology, Amsterdam, The Netherlands; 7 Amsterdam University Medical Centers, Radiation Oncology, Amsterdam, The Netherlands; 8 Radiotherapy Institute Friesland, Radiation Oncology, Leeuwarden, The Netherlands; 9 First Faculty of Medicine, Charles University and General University Hospital, Obstetrics and Gynaecology, Prague, Czech Republic; 10 Catharina Hospital, Radiation Oncology, Eindhoven, The Netherlands; 11 Erasmus MC – Cancer Institute, Radiation Oncology, Rotterdam, The Netherlands; 12 Institut Gustave Roussy, Radiation Oncology, Villejuif, France; 13 University Medical Center Groningen, Radiation Oncology, Groningen, The Netherlands; 14 St. Luke’s Hospital, Radiation Oncology, Dublin, Ireland; 15 Haaglanden Medical Center, Radiation Oncology, The Hague, The Netherlands; 16 University Medical Center Utrecht, Radiation Oncology, Utrecht, The Netherlands; 17 University Hospital Ghent, Radiation Oncology, Ghent, Belgium; 18 Comprehensive Cancer Centre Utrecht, IKNL, Utrecht, The Netherlands; 19 Leiden University Medical Center, Medical Statistics, Leiden, The Netherlands; 20 Leiden University Medical Center, Pathology, Leiden, The Netherlands Purpose or Objective The international PORTEC-4a trial was the first trial to incorporate molecular factors in decision making on adjuvant treatment for women with early stage high-intermediate risk endometrial cancer (HIR-EC). For patients allocated to the intervention arm, adjuvant treatment was based upon a molecular-integrated risk profile. The present analyses were performed to compare health-related quality of life (HRQL) and adverse event (AE) rates between the treatment arms in the first 6 months after randomisation. Materials and Methods Patients with HIR-EC were randomised (2:1) between individualised treatment based upon a molecular-integrated risk profile or standard vaginal brachytherapy (VBT). In case of a favourable profile, adjuvant treatment was omitted. Those with an intermediate profile received VBT while those with an unfavourable risk profile received pelvic radiotherapy (EBRT). HRQL was assessed with the EORTC-QLQ C30 and EN24 module at baseline, after treatment and 6 monthly after randomisation. AE were graded using the CTCAE v4.0. Analyses were performed on the per-protocol population. Prevalence of toxicity was calculated at each timepoint and compared using Fisher’s exact test. Analysis of HRQL was done according to the EORTC guidelines. Symptoms rated as “quite a bit” or “very much” were considered ‘severe’. A 2-sided p<0.01 was considered statistically significant, and p<0.05 reported as a trend. Results Between 2012 and 2021, 563 evaluable patients were included, 367 in the molecular arm vs 196 in the standard arm, see figure 1. In 46.7% of patients in the molecular arm adjuvant treatment was omitted. Grade ≥ 2 AE were reported in 59 patients at completion of treatment: 41 (11.4%) in the interventional arm vs 18 (8.9%) in the standard arm (p=0.39); at 6 months, this was 44 (12.2%) vs 22 (10.9%), p=0.36. Grade 3 AE were reported for 4 patients (3 in the molecular arm and 1 in the standard arm) at treatment completion, and for 8 (4 vs 4) at 6 months. There were no grade 4 or 5 AE. During treatment all grade 3 AE were genitourinary or vaginal, whereas at 6 months only 1 was related to treatment. 94.7% completed HRQL assessment at baseline, 81.0% during treatment and 82.2% at 6 months. No significant differences between the two arms were found for physical functioning (p=0.31) and global health status (p=0.10). Social and role functioning improved over time in both arms (p<0.001). A trend for better role functioning over time was seen for patients treated according to their molecular profile compared to standard VBT (p=0.014).