Vaccines may save one in 10 cancer victims, say scientists
By Celia Hall, Medical Editor
Thousands of cancers will be prevented every year in Britain as specific vaccines are developed, scientists at the leading cancer charity predict today.
A report from Cancer Research UK says that in time one in 10 cancers could be prevented by vaccines and they estimate that a quarter of cancers in the developing world are triggered by a handful of infections.
One in three people will have some form of cancer in their lifetime and more than 275,000 new cancers are diagnosed in Britain each year. Breast, lung, bowel and prostate cancers account for more than half of them.
The authors stress that people cannot "catch" cancer like a cold. Rather some viruses can initiate disease in a proportion of susceptible people.
Although only a small proportion of virus-infected people develop these cancers, the global number of virus-associated cancer accounts for more than 1.8 million cases of cancer each year - which is around 18 per cent of all new cancer cases worldwide.
Human papilloma virus (HPV) is present in the majority of cervical cancer cases and the first vaccine against HPV is expected to reach the market later this year.
Nearly half a million cases are diagnosed worldwide and almost 3,000 in the UK each year. Experts believe that HPV vaccine could prevent about 70 per cent of cervical cancer.
Prof Alan Rickinson, from the Cancer Research UK Institute at the University of Birmingham and lead author of the report, said: "Studying the association between infectious agents and human cancers is extremely important because, in such cases, infection represents one defined link in the chain of events leading to cancer development.
"Knowing this helps us to trace other links in the chain and to understand how the whole chain fits together. More importantly, if we can break the chain by preventing the infection through vaccination, then we can prevent the cancer developing."
The report says that almost all kinds of cancer develop through a series of genetic accidents. When the accidents accumulate, a cell can become cancerous. For some sorts of cancer, such as cervical cancer, one of these genetic accidents is linked to infection.
Other cancers linked to viruses include liver cancer, cancer of nasal passages, some lymphomas and rare forms of leukaemia.
Many cases of stomach cancer are also linked to a common bacterial infection.
A vaccine has also been developed for the Hepatitis B virus which is linked to liver cancer. There are 340,000 cases of primary liver cancer worldwide - half are linked to the Hepatitis B virus. There are 2,784 cases of this cancer in the UK each year but a much lower percentage of these are linked to the virus.
Dr Anne Szarewski, clinical consultant at Cancer Research UK, said the work on cervical cancer was "the most exciting development" in many years.
Cancer Research UK is continuing to fund research into possible links between other cancers and underlying infection. Prof John Toy, medical director of the charity, said: "As today we successfully vaccinate against infectious diseases so we shall soon be able to vaccinate against certain types of cancer."