Regular aspirin use may help reduce risk of bile duct cancer

Regular use of aspirin was linked with a significantly reduced risk of developing bile duct cancer, also called cholangiocarcinoma, in a recent study. The findings, which are published in the journal Hepatology, indicate that additional research on the potential of aspirin for preventing bile duct cancer is warranted.

Evidence has been accumulating that regular, long-term use of aspirin is associated with decreased risks for several cancer types, especially gastrointestinal cancers. To investigate the potential of aspirin for preventing bile duct cancer, a team led by Jonggi Choi, MD, Roongruedee Chaiteerakij, MD, PhD, and Lewis Roberts, MB ChB, PhD, of the Mayo Clinic College of Medicine in Rochester, MN, conducted one of the largest hospital-based case-control studies evaluating risk factors for bile duct cancer in Western populations. Their study included 2395 patients with bile duct cancer who were seen at the Mayo Clinic from 2000 through 2014, and 4769 healthy controls who were matched with patients by age, sex, race, and residence. A total of 591 (24.7 percent) bile duct cancer patients and 2129 (44.6 percent) controls took aspirin.

The researchers found that individuals who took aspirin had a 2.7-fold to 3.6-fold reduced likelihood of having bile duct cancer compared with those who did not take aspirin. In addition to finding an inverse association between aspirin use and the presence of bile duct cancer, the team discovered that primary sclerosing cholangitis (an inflammatory condition that causes scars within the bile ducts), biliary tract diseases, cirrhosis, hepatitis B virus infection, diabetes, and smoking conferred risks of different magnitudes for the three different bile duct cancer subtypes. This supports the hypothesis that bile duct cancer subtypes are distinct diseases with their own risk factors.

“Chronic persistent inflammation is one of the key elements that promotes cancer of the bile ducts, and well-known risk factors for bile duct cancer have all been shown to increase the risk for bile duct cancer by inducing chronic inflammation of the ducts,” explained Dr. Choi. “Aspirin is an anti-inflammatory agent and may reduce the risk of bile duct cancer by reducing inflammation through inhibition of the cyclooxygenase enzyme. Previous studies have shown that aspirin also blocks additional biological pathways that promote cancer development.”

Dr. Chaiteerakij noted that it remains to be seen whether aspirin is safe and cost-effective for the purpose of protecting against bile duct cancer. “Until now, there has been little evidence of a potential role for aspirin in the prevention of bile duct cancer. Our study provides the first evidence for this,” she said. Additional confirmatory results are needed before aspirin can be recommended as a chemopreventive agent for bile duct cancer, added Dr. Roberts. “The next steps should include population-based studies examining the associations of aspirin use with risk of bile duct cancer and also clinical trials, particularly in populations at high-risk for bile duct cancer, to confirm the benefit of aspirin for bile duct cancer prevention.”