Factors associated with the development of extrahepatic malignancy in patients with nonalcoholic fatty liver disease: a single-center longitudinal study

Background and aims: The aim of the present study was to determine incident cases of extrahepatic malignancy in patients with nonalcoholic fatty liver disease (NAFLD) and to identify whether the factors are associated with cancer development.

Methods: Between 15 January 2001 and 14 March 2021, a total of 1365 patients had been diagnosed with NAFLD were enrolled in the study.

Results: The median follow-up period was 59.5 months. The mean age was 50.9 ± 10.9 years. The female gender was predominant (57%). During the follow-up period, 62 extrahepatic malignancies and 11 hepatocellular carcinomas were identified. Of all extrahepatic malignancies, 51 were solid organ malignancies and 11 were hematological malignancies. Female breast cancer was the most frequent (25.8%), followed by thyroid cancer (19.4%), lymphoma (12.9%), and lung cancer (9.7%). In univariate and multivariable analyses, after adjusting for age and sex, the presence of diabetes and high initial baseline gamma glutamyl transpeptidase (GGT) levels were significantly associated with the development of extrahepatic malignancies [hazard ratio (HR) = 1.82, 95% confidence interval (CI): 1.04-3.20, P = 0.036] and HR = 1.96, 95% CI: 1.14-3.38, P = 0.015, respectively). In 424 biopsy-proven NAFLD patients, the development of extrahepatic cancer was significantly associated with the severity of hepatic fibrosis (HR = 3.31, 95% CI: 1.36-8.07; P = 0.008).

Conclusion: Extrahepatic malignancies are frequently seen in patients with NAFLD. Diabetes mellitus, high baseline GGT levels, and significant hepatic fibrosis are associated with the development of extrahepatic cancer in patients with NAFLD.