ESTRO 2023 - Abstract Book

S722

Monday 15 May 2023

ESTRO 2023

The prognostic value of SMI was investigated in Kaplan-Meier curves and multivariable Cox models accounting for age, sex, performance status (PS), feeding tube insertion pre-RT, O’Rourke dysphagia score, T & N stage, histology, specific tumour site and pre-RT BMI. The interaction between BMI and SMI was also investigated. The primary endpoint was overall survival (OS). Results Automatic segmentation was successful for 96% of cases. Kaplan-Meier curves split on sex-specific median SMI showed a significant difference in OS ( p=0.025 ; Fig1(a)). Sarcopenic patients had a median survival time of 534 days compared to 993 days for non-sarcopenic patients. In Cox models, SMI was found to be a prognostic factor ( p=0.04 ; Fig2) alongside pre-RT feeding tube insertion, histology and N stage, where increased SMI was protective. The interaction between BMI and SMI was also a significant factor ( p=0.04 ), which suggests that the effect of SMI on OS varies with BMI. This is shown in Fig1(b) where the effect of SMI on OS is different for different BMI sub-groups (underweight & normal vs. overweight & obese). The adverse effect of low SMI was strongest in low BMI patients. Whereas, SMI was not an independent prognostic factor in overweight/obese patients.