[18F]FDG PET/CT beyond staging: Prognostic significance of sarcopenia and adipose tissue metabolism in esophageal carcinomas.

Abstract

Aim: This study aimed to investigate the relationship between PET and CT parameters and sarcopenia, adipose tissue, and tumor metabolism in esophageal carcinoma (EC) and its impact on survival in EC.

Method: Our study included 122 EC patients who underwent PET/CT for staging. Muscle and adipose tissue characteristics were evaluated, including lumbar (L3) and cervical (C3) muscle areas, psoas major (PM) and sternocleidomastoid muscle (SCM) parameters, and PET parameters for visceral and subcutaneous adipose tissue (SAT). Sarcopenia was determined using CT images, with a threshold for muscle tissue at the L3 vertebral level, and its impact on overall survival (OS) was investigated.

Results: Sarcopenia was detected in 48 patients. SULmax in the primary tumor (PT) was significantly higher in sarcopenic patients (SP). The frequency of distant metastasis was higher in SP and OS was significantly lower. In the locally advanced stage, sarcopenia status decreased survival. L3, PM, C3, and SCM muscle areas were highly correlated. Subcutaneous adipose tissue SUVmax was significantly increased in SP and those with distant metastasis. Univariate analysis identified PT SULmax, PT SUVmean, PT TLG, lymph node and distant metastasis, SAT SUVmax, and sarcopenia as poor prognostic factors, while multivariate analysis confirmed BMI, distant metastasis, PT SUVmean, PT TLG as independent predictors of OS.

Conclusion: This study demonstrated that sarcopenia, linked to reduced survival, correlates with primary tumor SULmax, distant metastasis, and subcutaneous tissue PET parameters, exerting a notable impact on survival, particularly in locally advanced stages. Attenuation-corrected CT can be used instead of diagnostic CT, and sarcopenia can be diagnosed using not only L3 but also C3 slices.