Metabolic Activity of Visceral Adipose Tissue Is Associated with Metastatic Status of Lymph Nodes in Endometrial Cancer: A ¹⁸F-FDG PET/CT Study

Obesity contributes to increased cancer incidence and aggressiveness in patients with endometrial cancer. Inflamed metabolic activity of visceral adipose tissue (VAT) is regarded as a key underlying mechanism of adverse consequences of obesity. The aim of this study was to investigate the association between inflammatory metabolic activity of VAT evaluated by 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) and metastatic status of lymph nodes (LN) in patients with endometrial cancer. In total, 161 women with newly diagnosed endometrial cancer, who received preoperative 18F-FDG PET/CT, were enrolled. VAT inflammatory metabolic activity was defined as V/S ratio and measured from the maximum standardized uptake value (SUVmax) of VAT normalized to the SUVmax of subcutaneous adipose tissue (SAT). The positive LN metastasis group exhibited a significantly higher V/S ratio than the negative LN metastasis group. Systemic inflammatory surrogate markers including high sensitivity C-reactive protein, spleen SUVmax, and bone marrow SUVmax were also higher in the LN metastasis group than in the negative LN metastasis group, showing significant correlations with V/S ratio. In multivariate logistic regression analysis, V/S ratio was independently associated with LN metastasis. V/S ratio is independently associated with the LN metastasis status in patients with endometrial cancer. This finding could be useful as a potential surrogate marker of obesity-induced VAT inflammation associated with tumor aggressiveness.