The Cancer Journal - Volume 10, Number 5 (September-October 1997)
Taiwan: in the lead for prevention of malignant hepatoma
Taiwan is the first country to undertake, and to complete, a programme of generalized vaccination against hepatitis B. Six years after starting this programme (1), the results are more than encouraging with respect to hepatocellular cancers in children, both the incidence and mortality of which have been markedly reduced.
Vaccination was first given to new-born infants exposed to the diseases, then to all neonates. The programme was then rapidly extended to all children and, after six years, to adults.
Before vaccination, the incidence of malignant hepatoma in children aged between 6 and 14 years was 0.70/100,000; it fell to 0.36/100,000 ten years after starting vaccination. Two factors were certainly involved : firstly, a progressive increase in the number of immunized children, since 85-90% of the pre-school and school population were vaccinated, and secondly, the "herd immunity" created by the large number of immune individuals. The mortality due to hepatocellular cancer declined in parallel with its incidence.
The methodological rigor of this study and the efficiency of screening produced a paradoxical rise in the incidence of hepatoma in adults. This must have been an increase in the number of cases diagnosed rather than an absolute increase. However, increased life expectancy and a possible role of hepatitis C virus are two contributing factors which should not be neglected (2).
Those who know of this programme and its initial results cannot deny that Taiwan is ahead of the rest of the world in the prevention of hepatitis B and its consequences. The reduction in the number of infantile hepatomas is in itself a modest return for the level of investment, but it probably heralds a progressive fall in the incidence of post-hepatitis cirrhosis and malignant hepatoma in adults. This health care initiative undertaken at a relatively early stage in the economic development of a country with 21 million inhabitants stimulates our curiosity to know exactly which health care sectors have been given priority by the political, administrative and medical authorities of this country. Their investment is likely to reap considerable benefits in terms of lives saved in a few years time, when the incidence of cirrhosis and hepatoma, extremely frequent diseases in South-East Asia, begins to decline.
Mass vaccination against hepatitis B virus has been recommended by the WHO since the beginning of the 1980s. It would be interesting to know what decided one single country to put this into action, and to succeed, even if the rest of the programme turns out to be less positive than the first stage.
- Should neonatal vaccination be continued and for how long?
- Which other branches of a vaccination programme designed to reduce the risk of cancer could, and should, be implemented in high-risk countries? Obviously, papillomavirus and Epstein-Barr virus spring to mind; these vaccines exist but are neither commercially available nor used in large-scale experimental studies, because, among other reasons, there is no "market" for them.
When will the so-called developed countries face up to their responsibilities: to use, when scientifically appropriate, their technological advances in large-scale prevention programmes and go beyond both the commercial viewpoint which takes into account only market profits and the charitable approach which seeks to save lives without undertaking more far-sighted actions with lasting results? Only State authorities, alone or in concert, can act effectively on a country-wide scale. Industrialized countries should overcome their internal problems to show the political maturity necessary for this sort of programme.
In any case, Taiwan has taken the lead in this field, and international authorities should recognize this without reserve.
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1. Chang M-H, Chen C-J, Lai M-S et al. Universal hepatitis B vaccination in Taiwan and the incidence of hepatocellular carcinoma in children. N. Engl. J. Med. 336, 1855-1859, 1997.
2. Liaw Y-F. Dual infection with HBV and HCV in hepatocellular carcinoma. (review) Cancer J. 10, 189-192, 1997.