Cancer Risks with STIs

The three most common Sexually Transmitted Infections (STIs) known to cause or increase the risk of cancer are:

  • Human Papillomavirus (HPV)
  • Hepatitis B and C
  • HIV

HPV

While HPV infections are very common, cancer caused by HPV is not. Most people infected with HPV will not develop a cancer related to the infection. However, some people with long-lasting infections of high-risk types of HPV are at risk of developing cancer. According to the Centers for Disease Control and Prevention (CDC), HPV is thought to be responsible for more than 90% of anal and cervical cancers, about 70% of vaginal and vulvar cancers, and 60% of penile cancers. Cancers in the back of the throat (oropharynx) traditionally have been thought to be caused by tobacco and alcohol, but recent studies show that about 60% to 70% of cancers of the oropharynx may be linked to HPV contracted during oral sex. Many of these oral cancers may be caused by a combination of tobacco, alcohol, and HPV.

Hepatitis B and C

According to the American Cancer Society, both Hepatitis B virus (HBV) and Hepatitis C virus (HCV) cause viral hepatitis, a type of liver infection. In the United States, almost half of liver cancers are linked to HBV or HCV. Some research suggests that long-term HCV infection may be linked to non-Hodgkin lymphoma. People with chronic HBV infections have a higher risk for liver cancer.

HIV 

People who have an advanced stage of the human immunodeficiency virus (HIV) or AIDS are at a higher risk for some types of cancer. While HIV does not seem to directly cause cancer, people living with HIV or AIDS are at an increased risk of many types of cancers because of a weakened immune system. According to the National Cancer Institute, people infected with HIV are 500 times more likely to be diagnosed with Kaposi sarcoma, 12 times more likely to be diagnosed with non-Hodgkin lymphoma, and 3 times more likely to be diagnosed with cervical cancer. People with HIV infection also have a higher risk of dying from cancer than people without an HIV infection with the same cancers.

Can vaccinations prevent a cancer-causing STI? 

  • Vaccinations are available for certain types of HPV (including types that are linked to HPV-related cancers, as well as types linked to anal and genital warts).
  • Vaccinations are available for Hepatitis B and Hepatitis C. However, vaccinations for HPV and Hepatitis B & C will not protect someone from someone who has already acquired those STIs.
  • There is currently no vaccination that prevents HIV.

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