Infections Cause 1 in 6 Cancer Cases Worldwide
Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses were responsible for 1.9 million cases of mainly gastric, liver, and cervix uteri cancers.
Around 2 million cancer cases each year are caused by infectious agents, according to a study published in The Lancet Oncology.
Infections with certain viruses, bacteria, and parasites have been identified as strong risk factors for specific cancers, researchers said.
Researchers considered infectious agents classified as carcinogenic to humans by the International Agency for Research on Cancer. They calculated their population-attributable fraction worldwide and in eight geographical regions, using statistics on estimated cancer incidence in 2008.
Of the 12.7 million new cancer cases that occurred in 2008, the population-attributable fraction (PAF) for infectious agents was 16.1 percent, meaning that around 2 million new cancer cases were attributable to infections. This fraction was higher in less developed countries (22.9 percent) than in more developed countries (7.4 percent) and varied from 3.3 percent in Australia and New Zealand to 32.7 percent in sub-Saharan Africa.
Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses were responsible for 1.9 million cases of mainly gastric, liver, and cervix uteri cancers. In women, cervix uteri cancer accounted for about half of the infection-related burden of cancer; in men, liver and gastric cancers accounted for more than 80 percent. Around 30 percent of infection-attributable cases occur in people younger than 50 years.
Application of existing public health methods for infection prevention, such as vaccination, safer injection practice, or antimicrobial treatments could have a substantial effect on the future burden of cancer worldwide.