ESTRO 2025 - Abstract Book

S874

Clinical - Gynaecology

ESTRO 2025

Conclusion: The results suggest that HYPO showed trend of improved LRC and OS while having similar intermediate-term outcomes across the conditions studied with CVRT and EMBRACE-II.

Keywords: EMBRACE, cervical cancer, hypofractionation

4128

Digital Poster Association between body composition and survival in gynecological cancer patients undergoing radiotherapy Artemis Bouzaki 1 , Alan McWilliam 1,2 , Donal McSweeny 1 , Claire Higham 3 , Peter Hoskin 4 , Azadeh Abravan 1,2 1 Division of Cancer Sciences, University of Manchester, Manchester, United Kingdom. 2 Advanced Radiotherapy, The christie NHS Foundation, Manchester, United Kingdom. 3 The Christie NHS Foundation, The christie NHS Foundation, Manchester, United Kingdom. 4 Clinical Oncology, The christie NHS Foundation, Manchester, United Kingdom Purpose/Objective: The role of body composition in cancer prognosis, particularly in gynaecological cancers, is underexplored. While body mass index (BMI) is commonly used as a risk factor, less attention has been given to how specific measures of body fat and muscle mass impact survival outcomes. This study examines the association between body composition metrics and survival in gynaecological cancer patients undergoing radiotherapy. Material/Methods: We conducted a retrospective analysis of 275 anonymised gynaecological cancer patients treated with radiotherapy at a single institution between 2008 and 2023. Body composition metrics such as skeletal muscle, intramuscular adipose tissue (IMAT), visceral fat, and subcutaneous fat were quantified at the L3 vertebral level from planning CT scans using an in-house toolkit. The skeletal muscle index (SMI) was imputed for patients without measurements of height using a linear model estimation accounting for age. The IMAT-to-skeletal muscle ratio was also calculated. Cox proportional hazards models (CPHMs) were used to assess the association of each metric with survival outcomes, adjusting for potential confounders: age, cancer stage, and performance status. Subgroup analyses were conducted for patients separated at the median age. Results: Body composition data were not calculated for 52 patients due to unavailable CT scans, leaving 223 patients for the analysis. The median age was 57 years. In univariable analysis, IMAT-to-skeletal muscle ratio was significant (HR = 4.3, p < 0.01) suggesting a 13% increase in risk per 0.1 unit increase in the ratio. SMI was also significant in univariable analysis (HR = 0.95, p < 0.01) (Figure 1). However, when adjusted for potential confounders in multivariable analysis none of the body composition metrics remained statistically significant (Table 1). BMI was not significant in univariable or multivariable analysis. Subgroup analyses revealed no significant associations between survival and any body composition metric, including BMI, in either age cohort.