A recent review estimates that one in six cancers or two million a year globally, are caused by largely treatable or preventable infections.
The Lancet Oncology review, which looked at incidence rates for 27 cancers in 184 countries, found four main infections are responsible. These four are the human papillomaviruses (HPV), Helicobacter pylori and hepatitis B and C viruses. Together they account for 1.9m cases of cervical, gut and liver cancers.
The proportion of cancers related to infection is about three times higher in parts of the developing world than in developed countries – 22.9% versus 7.4%, respectively.
Among women, cancer of the cervix accounted for about half of the infection-related cancers. In men, more than 80% were liver and gastric cancers.
Drs Catherine de Martel and Martyn Plummer, who led the research, said: “Infections with certain viruses, bacteria, and parasites are some of the biggest and preventable causes of cancer worldwide. 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.”
Vaccines are already available to protect against HPV which is linked to cervical cancer and hepatitis B virus which is an established cause of liver cancer. It is already a known fact that stomach cancer can be avoided by clearing the bacterial infection H. pylori from the gut using a course of antibiotics.
Jessica Harris of Cancer Research UK said: “It’s important that authorities worldwide make every effort to reduce the number of infection-related cancers, especially when many of these infections can be prevented. In the UK, infections are thought to be responsible for 3% of cancers or around 9,700 cases each year.
“Vaccination against HPV, which causes cervical cancer, should go a long way towards reducing rates of this disease in the UK. But it’s important that uptake of the vaccination remains high. At a global level, if the vaccine were available in more countries, many thousands more cases could be prevented.”