Antihistamines vs Liver Cancer

Can they halve the risk of liver cancer in people with viral hepatitis?

Common antihistamines, usually used for the relief of allergies and hayfever, halved the risk of developing hepatocellular carcinoma (HCC or liver cancer) in people living with viral hepatitis during a 10-year follow-up period, according to a study published in Taiwan in January.

The review, published in the Journal of Clinical Oncology, showed people with hepatitis B who used H-1 antihistamines, which are the type used for allergy relief * , on at least 120 days in the follow-up period reduced the risk of liver cancer by a startling 60%.

People with hepatitis B who took fewer antihistamine doses had a smaller reduction in risk, although those with the lowest exposure (28- 42 daily doses) still had a dramatic 40% reduction in the risk of liver cancer. The study also found similar dose-response relationships were seen in people with hepatitis C and in people with both hepatitis B and C.

The researchers in Taiwan were inspired by previous evidence that H-1 antihistamines might have anti-cancer properties, and by what they see as the unsatisfactory outcomes of treatment for people with advanced liver cancer.

The study used the Taiwan National Health Insurance Research Database to identify people with viral hepatitis, assess their H-1 antihistamine exposure and calculate their risk of HCC.

The researchers identified 521,071 people with hepatitis B, 169,159 people with hepatitis C and 39,016 people with both viruses who received health care in Taiwan between 2006 and 2015. The study excluded people diagnosed with HCC less than a year after a diagnosis of viral hepatitis or with missing data. These people were then divided into those using H-1 antihistamines and those not, and the two groups matched and compared.

The cumulative incidence rate of HCC was significantly lower in H1-antihistamine users in each group after 10 years of follow-up. After adjusting for age, sex and co-morbidities, the risk of HCC was 51% lower in people with hepatitis B who used antihistamines, and 52% lower for people with hepatitis C using antihistamines. The risk was 53% lower in people with both hepatitis B and C who used the antihistamines.

People with viral hepatitis were significantly less likely to develop HCC if they had been prescribed non-steroidal anti-inflammatory drugs (NSAIDS), aspirin or statins. The researchers say that the relationship between aspirin, NSAIDS and HCC risk needs to be clarified by further research, but they point out that their finding regarding statins and reduced HCC risk confirms separate cohort studies in people with hepatitis B and C.

The researchers note that their findings suggest that further research is needed to understand the mechanism by which H1-antihistamines might reduce the risk of HCC, and to clarify whether they could serve as a treatment. Readers should always seek advice from their doctor regarding liver cancer prevention.

See the original study at bit.ly/3IAkIR3.

* There are also H-2 antihistamines, which are used to treat gastrointestinal conditions such as acid reflux, indigestion and stomach ulcers.