Obesity Is Protective Factor in Hepatocellular Carcinoma

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Introduction: The incidence of hepatocellular carcinoma (HCC) has been increasing significantly with the nationwide epidemic of obesity. The relationship between obesity, metabolic syndrome, nonalcoholic fatty liver disease (NAFLD) is well established. However, as HCC is heterogeneous regarding etiology and severity of concurrent cirrhosis, the overall role of obesity in HCC warrants more investigation. This study aims to characterize prevalence of obesity in HCC patients, assess association of obesity with tumor characterstics and prognosis. Methods: We retrospectively analyzed patients with diagnosis of hepatocellular carcinoma (by ICD-9 code) at a large public hospital during 10 years (05/2006 through 05/2015). HCC was confirmed with characteristic radiologic features and/or histology from liver biopsy. Patients are categorized according to body weight index (BMI) at diagnosis of HCC as underweight (2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), Class I Obesity (30-34.9 kg/m2), Class II Obesity (35-39.9 kg/m2), Class III Obesity (≥ 40 kg/m2). HCC is categorized according to etiology into viral, alcoholic, viral-alcoholic, nonviral-nonalcoholic. We constructed multivariable regression model of mortality with STATA 13. Results: 270 patients were included of which 13(4.81%) were underweight, 99(36.7%) normal weight, 78(28.9%) overweight, 50 (18.5%) Class I obese, 15(5.6%) Class II obese, 15(5.6%) Class III obese. There was no difference in mean BMI by severity of cirrhosis. However there was significant difference of mean BMI by etiology (p < 0.0001): nonviral-nonalcoholic HCC showed significant higher BMI. Higher BMI is associated with extra-hepatic metastasis (p=0.026), however there's no difference in tumor number and size. BMI is independent risk factor for venous thromboembolic event (VTE) (OR 1.15, p=0.020; CI 1.02-1.29), and independent protective factor for mortality (OR=0.92 p=0.038; CI: 0.84-0.99). After exclusion of patients with prior paracentesis (70/270), protective effect of BMI persists (OR 0.86, p=0.007; CI 0.77-0.96). Conclusion: Patients with HCC of different etiologies have significantly different BMI: nonviral-nonalcoholic-HCC which mostly represent (NAFLD) is associated with higher BMI. Higher BMI is associated with extra-hepatic metastasis and risk of VTE. BMI is not risk factor for hospice or preclusion from curative treatment. However interestingly higher BMI showed protective effect against mortality.