Regular aspirin use is associated with an approximately threefold reduction in risk for the three major subtypes of cholangiocarcinoma, results of a case-control study indicate.
In a study comparing patients with bile duct cancers with matched controls, aspirin use was associated with a 65% reduction in risk for intrahepatic cholangiocarcinoma (CCA), 66% reduction in risk for perihilar CCA, and 71% reduction in risk for distal CCA, reported Dr. Jonggi Choi and colleagues from the Mayo Medical School in Rochester, Minn.
“This is one of the largest hospital-based case-control studies evaluating risk factors for CCA in Western populations. We found that aspirin use had a significant inverse association with CCA development,” they wrote in Hepatology (2016. doi: 10.1002/hep.28529).
They also found that other disorders, including primary sclerosing cholangitis (PSC), non–PSC related cirrhosis, biliary tract diseases, hepatitis B infections, and diabetes, as well as smoking, were associated with varying magnitudes of risk for different CCA subtypes.
“This supports the hypothesis that the three CCA subtypes are distinct diseases and that each subtype thus has its own susceptibility to risk factors,” they wrote.
The investigators conducted a case-control study to look at various risk factors for CCA using data on all patients seen for CCA at the Mayo Clinic in Rochester from 2000 through 2014. Each case was matched by age, race, sex, and residence to two controls, chosen from among patients enrolled in the Mayo Clinic Biobank.
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There were a total of 2,395 cases (1,169 with intrahepatic CCA, 995 with perihilar CCA, and 231 with distal CCA) and 4,769 controls. In all, 24.7% of cases and 44.6% of controls had used aspirin.
In multivariate logistic regression analysis controlling for demographic factors, obesity, hypertension, diabetes, stroke, coronary artery disease, peripheral vascular disease, atrial fibrillation, nonalcoholic fatty liver disease/nonalcoholic steatohepatitis, PSC, cirrhosis, irritable bowel disease, and smoking status, aspirin was significantly associated with a reduction in risk for all CCA subtypes with adjusted odds ratios (AOR) of 0.35 for intrahepatic CCA, 0.34 for perihilar cancer, and 0.29 for distal CCA (P for all less than .001).
In addition, they found that PSC was strongly associated with risk for perihilar CCA (AOR 453; P less than .001), intrahepatic CCA (AOR 93.4, P less than .001), and distal CCA (AOR 34.0, P = .002).
Cirrhosis not related to PSC was also associated with intrahepatic and perihilar CCA (AOR 13.8 and 14.1, respectively, P less than .001 for each), but not with distal CCA. Isolated inflammatory bowel disease without PSC was not associated with elevated risk of any CCA subtype.