Medically reviewed by Sarah Feldman, MD, MPH
Human papillomavirus (HPV) is a virus that can cause abnormal tissue growth and other changes to cells. It can be spread through skin-to-skin contact during sexual activity, and it can be carried by all sexes. There are over 100 different types (or strains) of the virus, which are considered either “low-risk” (because they cause warts) or “high-risk” (meaning they have the potential to cause cancer).
While most people who are infected with HPV do not develop cancer, there are ways that you can reduce your risk of contracting HPV.
Which cancers can be caused by HPV?
High-risk strains of HPV causes approximately 5 percent of cancers worldwide, including:
There are approximately 12 to 14 high-risk strands of HPV, but strands 16 and 18 are responsible for the majority of HPV-caused cancers. In fact, these two strands cause 70% of all cervical cancers, and can also cause the majority of oropharyngeal, vaginal, vulvar, and penile cancers.
Although cervical cancer is the most common HPV-related cancer worldwide, oropharyngeal cancer now exceeds the rate of cervical cancer in the U.S. and is the most common HPV-related cancer in men.
How are cancers caused by HPV?
When a high-risk HPV infects the cells of the cervix, oropharynx, vulva, vagina, penis, or anus, it can result in changes to cells, and these altered cells have the potential to develop into cancer if they are left untreated. Fortunately, most HPV infections clear before causing precancerous changes, and it is only persistent infection with a high risk subtype that increase the risk for cancer.
How can I reduce the risk of HPV-related cancer?
The first step to reducing the risk of developing HPV-related cancer is to prevent the risk of contracting HPV. Vaccination against the HPV virus is currently recommended for all children ages 9-14 regardless of gender, with catch-up until age 26. Although not proved to prevent cancer in patients over age 26, it may be offered after appropriate counseling up to age 45. People with a cervix aged 21 or over should have screening with Pap testing every three years until aged 30, and then Pap and HPV testing thereafter every 5 years if all results are normal. Patients who have had abnormal results previously may need more frequent testing.
Vaccines
Vaccines prevent HPV infections that may lead to cancer. Gardasil is the only approved vaccine in the US at this time and it prevents infection with 7 high risk HPV types, accounting for roughly 90% of cancers if given before the onset of sexual skin to skin contact. It also protects against two HPV types (6 and 11), which are responsible for the majority of genital warts.
The Centers for Disease Control and Prevention (CDC) recommends HPV vaccination for both boys and girls between the ages of 9 and 14, ideally between ages 11 and 12. It is important to be vaccinated early, before the onset of sexual activity; vaccines cannot prevent cervical cancer if the patient has already been infected with the virus.
Safe sex
You can lower your risk of contracting HPV by using a condom every time you have sex. You can still contract HPV in areas left exposed by the condom, so it isn’t considered a substitute for the vaccination. Still, condoms can provide some protection from HPV as well as other sexually transmitted infections.
Pap tests
Pap tests can help find abnormalities in the cervix that could be signs of pre-cancerous changes. During a Pap test, a clinician collects cells from the cervix. HPV testing can also be performed on the Pap test if indicated.