MEDICINE - UP TO THE MINUTE

by

Charles A. Bertrand, M.D., FACP, DIM-CD (Ret.)
Associate Clinical Professor of Medicine at New York Medical College
and at the Medical University of South Carolina

CANCER OF THE LIVER

A cancer cure? We would all love to see that but it isn't in the cards - certainly not at the present time. Each cancer seems to be different - the cell types vary, genetic factors are different, and other contributory factors are operative as well. These are just a few of the differences. For example, in melanoma of the skin the ultraviolet rays of the sun are crucial, in lung cancer the effects of cigarette smoking are drastic, in cancer of the liver it seems that the hepatitis B virus is important. One approach is to treat cancer - chemotherapy, as well as other modalities. But this is not the preferred method. The preferred method is to prevent cancer, if possible. This is what the Chinese on Taiwan attempted to do - to prevent cancer of the liver in children.

And they did it - with a considerable degree of success - by a nationwide immunization program. In an article entitled, "Universal Hepatitis B Vaccination in Taiwan and the Incidence of Hepatocellular Carcinoma in Children," published in The New England Journal of Medicine, Vol. 336, pp. 1855-1859 (June 26, 1997). Taiwan is a country of 21 million people. Cancer of the liver is prevalent in Taiwan, as it is in other Pacific rim countries. For years it has been suspected that hepatitis B is the key factor since the rate of seropositivity for hepatitis B antigen approaches 100% in children with this form of hepatocellular carcinoma. For this reason it seemed logical to Chinese preventive health experts to immunize neonates and this was begun in 1984. And so a massive immunization program was conducted throughout the entire country in that year and it is still being done at this time. To evaluate the outcome in children ages 6-14, three different methods were employed and one checked against the other. First, they used the national cancer registry, second, a childhood registration study, and third, a national mortality registry. By these three methods they believe that they have collected and found virtually all the cases of liver cancer in those years. As a control they used the incidence of brain tumors. Over this period of time there was no difference in the incidence of brain tumors, but a striking reduction in the incidence of cancer of the liver. They reported this over different time frames but, to generalize the numbers, the incidence declined from 0.7 per 100,000 children between 1981 and 1986 to a low of 0.13 for those born after the program was in effect for some time. In Figure 1 the authors indicate that "The incidence of liver cancer in children between 6 and 14 years old declined to zero for children born in 1986 and 1987." They further state that in the years from 1984 to 1986 carcinoma was diagnosed in only three children between the ages of six and nine among a population of about 2.3 million.

The key here is that this provides evidence that prevention of a viral infection in a population can reduce the incidence of a specific cancer. Who knows what other forms of cancer may be due to a virus?

A companion editorial in the same issue by Arie J. Zuckerman entitled, "Prevention of Primary Liver Cancer by Immunization," makes a number of interesting points. He says that up to 80% of hepatocellular liver cancers are attributable to the hepatitis B virus and that this is second only to tobacco among the known human carcinogens (cancer producing agent). He also points out that earlier studies done in Taiwan show that the risk of such cancer is 100 times greater in people who carry the hepatitis B virus as opposed to uninfected individuals. As far as mechanisms go, this editorial author said that a key event is the integration of the viral DNA into the host-cell chromosomal DNA where it acts on certain genes in the body. He concludes this editorial by saying that, "This study of the effect of vaccination in reducing the carrier rate of hepatitis B virus, with a concomitant reduction in liver cancer, leads us in the right direction and provides crucial evidence - and it represents a milestone in the annals of preventive medicine." And for cancer, preventive medicine is the best medicine.



The advice provided on this website is intended to be general in nature and should not be relied upon for specific treatment. If you need personal medical attention please contact your physician.


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