Reduced visceral adipose tissue area linked to early recurrence in HCC patients with HBV: a parallel mediation analysis.

[BACKGROUND] This study aims to evaluate the relationship between abdominal fat, as quantified by magnetic resonance imaging (MRI), and early postoperative recurrence (≤ 2 years) in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), with an emphasis on identifying potential mediators.

[METHOD] We enrolled HCC patients with HBV infection who underwent preoperative MRI and hepatectomy between January 2015 and October 2021. The visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas were measured at the third lumbar vertebra plane on T1-weighted images and compared between patients with and without early recurrence. Multivariate logistic regression models identified risk factors for early recurrence, which were then visualized in a nomogram. Mediation analysis assessed whether mediators explained the relationship between abdominal fat and early recurrence.

[RESULT] The study included 146 HBV-related HCC patients from institution A (internal cohort) and 76 from institution B (external validation cohort). Results showed that patients with early recurrence had smaller VAT areas (P=0.001, P<0.001) compared to those without early recurrence. The nomogram identified VAT areas (OR 0.92; 95% CI 0.86, 1.00) and microvascular invasion (MVI) (OR 2.29; 95% CI 1.08, 4.85) as significant risk factors in the internal cohort, and VAT areas (OR 0.65; 95% CI 0.48, 0.88) and MVI (OR 13.47; 95% CI 1.33, 136.27) in the external cohort. Mediation analysis revealed that MVI and tumor size partially mediated the relationship between VAT and early recurrence.

[CONCLUSION] Reduced VAT areas influence early recurrence in HBV-related HCC, with MVI and tumor size acting as mediators.