ESTRO 2025 - Abstract Book

S979

Clinical – Head & neck

ESTRO 2025

males, whereas in females, only albumin levels at the end of treatment were strongly associated with survival (p<0.001). Multivariable analysis identified baseline PA as an independent predictor of survival in males (p=0.026). 4o Conclusion: The results highlight pronounced gender-specific variations in the nutritional and metabolic responses of HNC patients undergoing CRT, underscoring the need for tailored, gender-sensitive nutritional interventions throughout treatment. Keywords: Malnutrition, gender, BIA

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Proffered Paper Impact of the introduction of “5+5” contouring on efficacy and swallowing outcomes in the phase 3 randomised CompARE trial. Charles Fong 1 , Piers Gaunt 2 , Paul Sanghera 1 , Agostino Cristaudo 3 , Annabell Allen 2 , Isla Humphreys 2 , Claire Gaunt 2 , Andrew Hartley 1 , Hisham Mehanna 4 1 Radiotherapy Department, Queen Elizabeth Hospital, Birmingham, United Kingdom. 2 Cancer Research UK Clinical Trials Unit (CRCTU), University of Birmingham, Birmingham, United Kingdom. 3 Rosemere Cancer Centre, Royal Preston Hospital, Preston, United Kingdom. 4 Institute for Head and Neck Studies and Education, University of Birmingham, Birmingham, United Kingdom Purpose/Objective: CompARE is a multi-arm multi-stage adaptive phase III randomised clinical trial evaluating the impact of alternative treatment regimens for escalating treatment of patients with intermediate and high-risk oropharyngeal cancer 1 . During recruitment to this study, centres were given the option to switch to a new contouring protocol incorporating the international “5+5” contouring protocol 2 . This exploratory analysis examines the impact of “5+5” contouring on local control, overall survival and swallowing outcomes. Material/Methods: The survivor functions for overall and local recurrence free survival were estimated using the Kaplan-Meier method and regression coefficients from a Cox regression model adjusting for trial treatment arms and stratification factors were used to estimate the hazard ratios for the “5+5” protocol compared to standard contouring protocol. The MD Anderson Dysphagia Inventory (MDADI) scoring questionnaire was completed by patients at regular intervals on the trial. Results: Between July 2015 and January 2024, 794 patients were randomised into the CompARE trial. The baseline characteristics of this population are; 17% High- risk OPC, 83% Intermediate-risk OPC, median age 58, 83% male, 78% ECOG PS 0. At the trial outset the standard contouring approach was employed for radiotherapy. However, from July 2020 the 5+5 regimen was increasingly adopted by a number of recruiting centres. Of those recruited, 771 patients underwent treatment that incorporated radiotherapy and reported the contouring approach undertaken as standard (N=496, 64%) or the 5+5 approach (N=275, 36%). The local recurrence free-survival at 36 months was; 85% (95%CI; 81%, 88%) for the standard contouring approach and 87% (95%CI; 82%, 91%) for the 5+5 approach. There was no significant difference in local recurrence free-survival using the new technique, adjusted hazard ratio 0.98 (95%CI; 0.57, 1.69). The overall survival at 36 months was; 82% (95%CI; 79%, 86%) for the standard contouring approach and 80% (95%CI; 70%, 87%) for the 5+5 approach. There was no significant difference in overall survival using the new technique, adjusted hazard ratio 0.88 (95%CI; 0.52, 1.51). The mean MDADI score at baseline was 77 (SD 17). At 12 months the MDADI was 68 (SD 17) for the Standard method and 72 (SD 17) for the 5+5 method