Early obesity and risk of cholangiocarcinoma in the United States.

Abstract

239 Background: In the United States, the incidence of intrahepatic cholangiocarcinoma (ICC) has been increasing over the last few decades. Despite the public health problem of obesity and the increasing incidence of ICC, the relationship between early adulthood obesity and ICC has never been examined in the American population. Methods: At the University of Texas MD Anderson Cancer Center we conducted a case-control study aimed at examining relationship between ICC and history of obesity after controlling for the potential confounding of several risk factors. Cases were patients with pathologically confirmed diagnosis of ICC. Controls were healthy subjects recruited from spouses of patients at MD Anderson who had cancers other than liver or gastrointestinal. Each case was frequency matched to 4 controls by age (± 5 years), sex, and race. Case patients and controls were interviewed for risk factors of liver cancer. A self-reported weight and body size pictogram at ages 20, 30, 40, 50, 60 was obtained from each participant. In 2016 we recruited 63 newly diagnosed patients with ICC who were compared to 252 healthy controls. Obesity was defined as body mass index (BMI) ≥ 30.0. Results: There was a significant 3 fold increase in ICC risk for obese individuals compared to those with normal weight. The estimated odds ratio (OR), 95%; confidence interval (CI) was 3.3 (1.3-9.1); P = .02. Obesity at the mid-20s, mid-30s, and mid- 40s was significantly associated with ICC risk; the estimated OR (95% CI) was 7.3 (2.8-19.7), 7 (2.4-20.9), and 4.8 (2-11.4), respectively. In addition, viral hepatitis, heavy alcohol use ( > 40 ml ethanol/day), and family history of cancer were significantly associated with ICC. Underlying radiological, pathological, or clinical evidence of steatosis, fibrosis, and cirrhosis was significantly observed in 25% ICC patients with early obesity. Conclusions: We concluded that early adulthood obesity is a significant risk factor for ICC in USA where underlying fatty liver diseases can be a significant factor for ICC progression. Integration of obesity with other ICC risk factors into a risk model may lead to identify high-risk individuals. Future collaboration with other US institutions is highly warranted to highlight the mechanism of obesity-induced ICC.