ESTRO 2021 Abstract Book

S204

ESTRO 2021

Figure 1. Kaplan Meier curves for LC, DFS and OS

Conclusion The present study reports a broad spectrum of therapeutic options in exclusive VC setting, which unfortunately have little impact on outcomes still remaining poor. Further prospective studies are warranted for a better treatment standardization in terms of prescription doses and volumes. OC-0298 Toxicity and patient-reported symptoms after 3D-conformal or intensity-modulated pelvic radiotherapy B. Wortman 1 , C. Post 1 , M. Powell 2 , P. Khaw 3 , A. Fyles 4 , R. D'Amico 5 , C. Haie-Meder 6 , I. Jurgenliemk-Schulz 7 , M. McCormack 8 , V. Do 9 , D. Katsaros 10 , P. Bessette 11 , M. Baron 12 , R. Nout 1 , K. Whitmarsh 13 , L. Mileshkin 14 , L. Lutgens 15 , H. Kitchener 16 , S. Brooks 17 , H. Nijman 18 , E. Astreinidou 1 , H. Putter 19 , C. Creutzberg 1 , S. de Boer 1 1 LUMC, Radiation Oncology, Leiden, The Netherlands; 2 Barts Health NHS Trust, Clinical Oncology, London, United Kingdom; 3 Peter MacCallum Cancer Center, Radiation Oncology, Melbourne, Australia; 4 Princess Margaret Cancer Center, Radiation Oncology, Toronto, Canada; 5 Azienda Socio Sanitaria Territoriale, Radiation Oncology, Lecco, Italy; 6 Institute Gustave Roussy, Radiotherapy, Villejuif, France; 7 University Medical Centre Utrecht, Radiation Oncology, Utrecht, The Netherlands; 8 University College London Hospitals NHS Foundation Trust, Clinical Oncology, London, United Kingdom; 9 Liverpool & Macarthur Cancer Therapy Centre, Radiation Oncology, New South Wales, Australia; 10 Città della Salute and Sant'Anna Hospital, Gynecologic Oncology, Turin, Italy; 11 University of Sherbrooke, Gynecologic Oncology, Sherbrooke, Canada; 12 Center Hospitalier Régional Universitaire de Besançon, Radiothereapy, Besancon, France; 13 The Clatterbridge Cancer Centre, Clinical Oncology, Bebington, United Kingdom; 14 Peter MacCallum Cancer Centre, Medical Oncology, Melbourne, Australia; 15 MAASTRO, Radiation Oncology, Maastricht, The Netherlands; 16 University of Manchester, Institute of Cancer Sciences, Manchester, United Kingdom; 17 Auckland City Hospital, Radiation Oncology, Auckland, New Zealand; 18 University Medical Centre Groningen, Gynecologic Oncology, Groningen, The Netherlands; 19 LUMC, Medical Statistics, Leiden, The Netherlands Purpose or Objective Over the past decades, radiation therapy (RT) techniques have developed from 3-dimensional conformal radiotherapy (3DCRT) to intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc techniques (VMAT), with increased conformality of the dose to the target volume with better sparing of the surrounding normal tissues. In the randomised PORTEC-3 trial, combined chemoradiotherapy was shown to improve survival for women with high-risk endometrial cancer compared to RT alone, albeit with increased short-term and long-term toxicities. The aim of the current analysis was to investigate whether IMRT, compared to 3DCRT, resulted in fewer adverse events (AE) and patient-reported symptoms in the PORTEC-3 trial. Materials and Methods Data on AE and health-related quality of life (QoL) of the PORTEC-3 trial was available for this analysis. Physician-reported AE were graded using CTCAE v3.0. Patient-reported QoL (using EORTC-QLQC30 and symptom items from CX24 and OV28) was measured at baseline, after RT, and at 6, 12, 18, 24, 36 and 60 months. AE and QoL were analysed and compared between 3DCRT and IMRT for the total study cohort and by treatment received. For patient-reported QoL combined scores 1-2 (“not at all” and “a little”) and 3-4 (“quite a bit” and “very much”) were compared between the two techniques by binary logistic regression, with scores of 3-4 considered as significant symptoms reported below. Results Among 660 evaluable patients participating in the PORTEC-3 trial, 333 received RT alone and 327 chemoradiotherapy; 559 received 3DCRT, 99 IMRT and for 2 the technique was unknown. Median follow-up was 74.6 months. Patient characteristics showed no significant differences between treatment arms and between the RT techniques. During treatment 43.6% had grade >2 gastro-intestinal and 43.3% haematological AE, with no significant differences between the techniques (p=1.00 and p=0.23). In the follow-up period, 15.4% versus 4.0% of patients had grade >2 diarrhoea after 3DCRT versus IMRT, respectively, p<0.01; 26.1% and 13.1% had grade >2 haematological AE, p<0.01. No significant differences were recorded for genitourinary AE. 574 (87%) patients were evaluable for QoL; 494 received 3DCRT and 80 IMRT. During treatment, 37.5% versus 28.6% of patients who had 3DCRT versus IMRT reported diarrhoea, p=0.125; 22.1% versus 10.0% bowel urgency, p=0.039, and 18.2% and 8.6% abdominal cramps, p=0.058 (Figure 1). At 1 year, 11.7% versus 3.8% (p=0.09) and 10.2% versus 5.8% (p=0.37), of patients reported diarrhoea or bowel urgency after 3DCRT versus IMRT. At 3 years, this was 11.2% versus 7.1% (p=0.34), and 9.2% versus 4.8% (p=0.39).