Cancer Prevention Benefits of the Hepatitis B Vaccine (Infographic)

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Of Aspirin, Ibuprofen, and Blood Tests: A Big Week in Liver Cancer Prevention

It's been a big week for liver cancer prevention - not something we often get a chance to write here at CNiC.  

As we reported on Tuesday, the US Preventive Services Task Force released new draft screening recommendations for the hepatitis C virus (HCV) - an infection that can greatly increase the risk of liver damage and later cancer.  Testing can find those who are infected and lead to therapies that can reduce risk.  

Now, come new results from a large government study linking aspirin use to a significantly lower risk of liver cancer.  The study, the National Institutes of Health-AARP Diet and Health Study followed over 300,000 men and women age 50 - 71 for multiple years and found that the use of aspirin and other non-steriodal anti-inflammatories (NSAIDS) - like ibuprofen and indomethacin -  lowered the risk of liver cancer by close to 40 percent and the risk of death from liver disease by just over 50 percent (study).  Aspirin use alone (without any other NSAIDS) was linked to a nearly 50 percent lower risk of liver cancer.  Just taking NSAIDS other than aspirin did not appear to lower risk of liver cancer but did lower the risk of death from liver disease by about 25 percent.  

The study didn't have information on the dosage of aspirin used by those in the study; so it's unclear whether low-dose aspirin (approximately 81mg) had similar benefits to full dose aspirin (typically 325mg).  Same for the non-aspirin NSAIDS.  

Previous studies looking at the link between aspirin/NSAIDS and liver disease were much smaller than this recent study and had inconclusive results. Yet, the manner in which aspirin works in the body fits nicely with a hypothesis of cancer prevention.  Inflammation is thought to play a potential role in the pathway from normal cells to cancer, so interrupting this pathway by keeping down inflammation - as aspirin and other NSAIDS do - is believed to be one possible way to cut the risk of certain cancers.

Regular long-term aspirin use is also linked to a lower risk of colon cancer (CNiC post).  And men age 45-79 and women age 55-79 are generally encouraged to take a daily aspirin to prevent cardiovascular disease (UPSTF guideline).  If these promising early results for liver cancer are replicated in other studies, it'll add even more weight to the evidence of health benefits with regular aspirin use.

As with all drugs, though, aspirin and other NSAIDS are not without certain risks.  Intestinal bleeding is a particular concern with aspirin and can be a very serious condition.  Those prone to bleeding - and other potentially serious side effects of NSAIDS - are usually discouraged from taking them.  Talking with a doctor is the best way to determine if the benefits of a regular aspirin outweigh the risks.  

It's estimated that Americans alone take an astounding 30 billion aspirins each year. Increasingly, it seems this may be money well spent.

Vaccination Against Hepatitis B Prevents Liver Cancer

As reported in the New York Times, San Francisco has launched an important public health campaign to promote vaccination against the hepatitis B virus which causes liver disease and liver cancer (story). This campaign is important for several reasons. Infection is usually silent and the impact on disease is many years after initial infection.

Prevention programs for cancer take different durations for the benefit to be observed. Vaccination programs offer one insight to the time frame of intervention and the ultimate reduction in cancer incidence. For cervical cancer prevention with human papilloma virus (HPV) vaccine, the current U.S. Center for Disease Control (CDC) recommends vaccination for women between ages 13 and 26; the benefit of this prevention will be observed many years hence. Hepatitis vaccination programs in Africa and Asia offer further illustration of these points. In the Gambia, a program launched in 1986 aims to evaluate the effectiveness of childhood vaccination with hepatitis B and current estimates are that the final outcome of reduced hepatocellular carcinoma in adults should be measurable from 2017 onwards. In Asia with nationwide hepatitis B vaccination implemented in Taiwan in 1984, results at 10 years show significant reduction in hepatocellular carcinoma in children. Clearly many years of follow-up are required to demonstrate protection of adults, though this outcome is implied by results to date.

The etiology of some 18 per cent of cancers worldwide can be linked to chronic infections due to agents such as Helicobacter pylori, human papillomaviruses (HPV), Hepatitis B, Hepatitis C, Epstein-Barr virus (EBV), human immunodeficiency virus (HIV), human herpes virus 8 (HHV-8), and Schistosoma haematobium, with the proportion of all cancer due to infections being much higher in developing countries (26 per cent, compared to 7.7 per cent in developed countries). The current burden of cancer in the developing world is dominated by infection, once smoking is accounted for. Of 10.8 million new cases of cancer worldwide (2002 figures), those caused by infectious agents are estimated as: H. pylori 5.5 per cent (mainly stomach, and lymphoma); HPV 5.2 per cent (mainly cervix, and ano-genital, mouth, pharynx); HBV and HBC 4.9 per cent (liver); EBV 1.0 per cent (nasopharynx, Hodgkin lymphoma and Burkitt lymphoma), HIV and HHV-8 0.9 per cent (Kaposi sarcoma, non-Hodgkin lymphoma) and other less common agents including schistosomes, HTLV-1, and liver flukes, less than 0.5 per cent. More than 25 per cent of cancer incidence in developing countries could be avoided if infectious causes of cancer were prevented. Successful vaccination programs have the potential to reduce cancer incidence and mortality; for example, Taiwan’s HBV vaccination program was initiated in 1984, and impressively high coverage rates (up to 97 per cent in 2004) have led to a consistent decline in hepatocellular cancer rates. However, a recent study by Chang et al. underscores the importance of a multi-pronged approach. Though Taiwan has seen a decrease in the incidence of hepatocellular cancer in children since initiation of the vaccination program (from 0.54 to 0.20 per 100,000 before and after the program), vertical transmission, vaccine failure, and the lack of hepatitis B immunoglobulin injection has affected program effectiveness and public health impact.

Given the burden of infection with the virus in Asian Americans in California, estimated at 10% it is not too early to begin a major campaign such as that instituted in San Francisco.