Every sixth cancer case germs cause cancer

Germs responsible for millions of cancers

09/05/2012

Millions of cancers are caused each year by infections with viruses or bacteria. These cancer cases could be avoided if sufficient infection protection or adequate medical treatment were provided worldwide. According to a recent study by the International Agency for Research on Cancer in Lyon, around 16 percent of the 12.7 million new cancer cases in 2008 were due to infections. In other words, around two million cancers could have been avoided if vaccines and medicines had been used to treat the infections, write Catherine de Martel and Martyn Plummer in the journal „Lancet Oncology“.

Every sixth cancer is caused by viruses or bacteria
The team led by Catherine de Martel and Martyn Plummer from the International Agency for Research on Cancer - an institution of the World Health Organization (WHO) - had evaluated the 2008 global cancer. They found that about one sixth of new cancers were due to bacterial or viral infections. „Of the 12.7 million new cases of cancer that occurred in 2008, 16.1 percent was due to pathogens, which means around 2 million new cancers“ caused by infections, write Catherine de Martel and colleagues. The infection in the less developed countries is much more likely to cause cancer than in the more developed countries. For example, the proportion of infectious cancer cases in developing countries averaged 22.9 percent, while in industrialized countries infections accounted for only 7.4 percent of new cancer cases.

The lowest proportion was found in researchers in Australia and New Zealand at 3.3 percent, and the highest in 32.7 percent in sub-Saharan Africa. In their study, the researchers evaluated cancer statistics from 184 countries, taking into account 27 different cancers.

1.5 million cancer deaths per year preventable
In terms of the approximately 7.5 million cancer deaths in 2008, the researchers found that around 1.5 million of these deaths worldwide were caused by an infection. According to the study, more than one million cancer deaths per year could be prevented if appropriate vaccine protection or adequate medical treatment were provided. „Infections with certain viruses, bacteria and parasites are one of the biggest and preventable causes of cancer worldwide“, so the statement of the researchers.

The most important preventable causes of infections that can lead to the formation of tumors, the experts called bacteria from the genus of Helicobacter pylori, hepatitis B and C viruses and human papilloma viruses. Overall, these pathogens are responsible for 1.9 million cancer cases - especially stomach, liver and cervix cancer. Cervical cancer accounts for around half of all infectious cancers in women, while 80 percent of men and women have liver and stomach cancer, write Catherine de Martel and Martyn Plummer. According to the researchers, about 30 percent of the infections caused by cancer affect people under the age of 50 years.

Preventive vaccinations and antibacterial drugs
Of the cancers that are caused by infections with viruses or bacteria, about 80 percent are attributed to poorer, less developed countries, which, according to the scientists, illustrates the need for action on the ground. This could be achieved with preventive vaccines and antibacterial drugs, a significant success in the fight against cancer, stressed the cancer researchers in the article „The global burden of cancer from infections in 2008“. Because infections by human papillomaviruses, hepatitis B and C viruses and bacteria such as Helicobacter pylori are preventable or in the case of the bacteria easily treatable. Goodarz Danaei of Harvard University in Boston, USA, commented in an accompanying commentary on the study results presented, for example, against human papillomaviruses and hepatitis B viruses „effective and comparatively cheap vaccines“ are available and therefore „a broader application priority for health systems in particularly stressed countries“ should have. (Fp)

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Image: Sebastian Karkus