Visceral Adipose Tissue Radiodensity Is Linked to Prognosis in Hepatocellular Carcinoma Patients Treated with Selective Internal Radiation Therapy

Abstract

Hepatocellular carcinoma (HCC) constitutes the fourth leading cause of cancer-related mortality. Various factors, such as tumor size, tumor multiplicity, and liver function, have been linked to the prognosis of HCC. The aim of this study was to explore the prognostic significance of muscle, subcutaneous and visceral adipose tissue (VAT) mass, and radiodensity, in a cohort of 101 HCC patients treated with selective internal radiation therapy (SIRT). Muscle and adipose tissue cross sectional area (cm²/m²) and radiodensity, reported as the Hounsfield Unit (HU), were determined using pre-SIRT computed tomography images. Cox proportional hazard models and exact logistic regression were conducted to assess associations between body composition and adverse outcomes. Majority of the patients were male (88%) with a mean VAT radiodensity of -85 ± 9 HU. VAT radiodensity was independently associated with mortality (HR 1.05; 95% CI: 1.01-1.08; p = 0.01), after adjusting for cirrhosis etiology, Barcelona Clinic Liver Cancer stage, previous HCC treatment, and portal hypertension markers. Patients with a high VAT radiodensity of ≥-85 HU had a two times higher risk of mortality (HR 2.01, 95% CI 1.14-3.54, p = 0.02), compared to their counterpart. Clinical features of portal hypertension were more prevalent in patients with high VAT radiodensity. High VAT radiodensity was associated with severe adverse events after adjusting for confounding factors. High VAT radiodensity is independently associated with both increased mortality and severe adverse events in patients treated with SIRT. VAT radiodensity measurement might serve as an objective approach to identify patients who will experience the most benefit from SIRT.

Keywords: CT attenuation; adverse events; body composition; mortality; radioembolization.

Figure 1

Survival curves in patients with high versus low visceral adipose tissue radiodensity. Survival over time was assessed using Kaplan–Meier curves and the curves were compared using the log-rank test. Shorter median survival was observed in patients with high visceral adipose tissue (VAT) radiodensity, compared to the patients with low VAT radiodensity (Log rank < 0.001).

Figure 2

Abdominal CT images taken at the 3rd. lumbar vertebra of patients with high versus low visceral adipose tissue radiodensity. Comparison of two HCC patients with the same visceral adipose tissue index (a) with a low visceral adipose tissue (VAT) radiodensity (−98 HU) and (b) with a high VAT radiodensity (−80 HU). Visceral adipose tissue with high radiodensity (−50 to −85) is shown in pink and low radiodensity VAT (−86 to −150) is shown in yellow. More than 75% of the total VAT area in Figure 2a represents the area composed of low-radiodensity VAT, whereas for Figure 2b the areas of high-radiodensity VAT is predominant (60%).

Figure 3

Scatter graph depicting correlations between visceral adipose tissue index and radiodensity. Negative moderately strong correlation (Pearson’s correlation) between visceral adipose tissue index (VATI) and VAT radiodensity in patients with HCC (r= −0.75, p < 0.001).