Risk of hepatic and extrahepatic cancer in NAFLD: A population‐based cohort study

BACKGROUND AND AIMS: Individuals with non‐alcoholic fatty liver disease (NAFLD) may be at greater risk of cancer. This study aimed to investigate the risk of hepatic and extrahepatic cancer compared to the general population in a population‐based cohort of patients with NAFLD. METHODS: We used the Swedish National Patient Registry from 1987 to 2016 to identify patients with a NAFLD diagnosis and no prior cancer. All patients with NAFLD were compared to up to 10 controls matched for age, sex and living location. The primary outcome was the first occurrence of any cancer as ascertained from national registries. As secondary outcomes, we analysed the risk of pre‐specified cancer subtypes. Cox regression models, adjusted for baseline diabetes, hypertension, hyperlipidaemia and chronic obstructive pulmonary disease were applied. RESULTS: We identified 8415 patients with NAFLD. Over a median follow‐up of 6.0 years (IQR 2.5–11.2 years), an increased risk for any cancer was found in patients with NAFLD compared to controls (9.7 vs. 8.6 cases per 1000 person‐years): hazard ratio (HR) = 1.22 (95% confidence interval, CI = 1.12–1.33). The risk for hepatocellular carcinoma (HCC) was particularly high (adjusted HR, aHR = 12.18, 95% CI = 7.15–20.79). The risk for some other cancer subtypes increased (colorectal [aHR 1.38], kidney [aHR 2.12], bladder [aHR 2.51] and uterine [aHR 1.78]), but was low in absolute terms. CONCLUSION: In this population‐based cohort, NAFLD was associated with an increased risk of developing cancer (especially HCC). The absolute risk for other forms of cancer was generally comparable to the control population.