Viruses and bacteria
The connection between infections and cancer is an important one. In developed countries, 7% of all cancer deaths are thought to be the result of viral and other infections.
Cancers associated with viruses or bacteria
- cervical cancer – human papillomavirus (HPV)
- liver cancer – hepatitis B (HBV) and hepatitis C virus (HCV)
- lymphomas – human T-lymphotropic virus 1 (HTLV-1)
- nasopharangeal cancer – Epstein-Barr (EBV)
- stomach cancer – helicobacter pylori (H. pylori)
Many of the viral infections associated with cancers cause clearly identifiable non-cancerous conditions (or precancers) before developing into cancer. Screening tests can help identify these signs – and if they are treated successfully – cancer may be prevented. Screening using the Pap test has reduced the incidence of cervical cancer because precancerous changes were detected and treated early.
The incidence of infection-related cancers in the US, Canada and in developing countries is increasing because of the AIDS virus.
Currently, there are vaccines for only HBV (hepatitis B virus) and HPV (human papillomavirus). Reducing the risk of infection remains the best way to help prevent some infection-related cancers. For example, using condoms may help prevent HBV and HPV infection.