It’s a fact that still flies under the radar for many people…the majority of anal and cervical cancers—and most cancers affecting the penis and oral cavity (mouth, throat and sinus cavities)—are linked to the human papillomavirus, or HPV, the most common sexually transmitted infection in the US.
Each year in the US, about 6,000 cases of anal cancer, approximately 11,000 cases of cervical cancer, 3,300 cases of vaginal or vulvar cancer, 900 cases of penile cancer and 13,000 cases of oropharyngeal cancer are attributed to HPV.
Why you should be informed about HPV: Even if you’ve been in a monogamous sexual relationship for years, you may unknowingly be carrying the potentially deadly virus. An estimated 80% of all sexually active men and women in the US (that’s about 79 million people) will be infected with HPV at some point in their lives, and about 14 million people become newly infected each year.
There are more than 100 strains of viruses in the humanpapilloma family. HPV is a well-known cause of warts on the genitals and elsewhere on the body (such as on the hands or feet). Two strains of HPV—type 6 and type 11—lead to genital warts, while more than 30 strains can cause warts on other parts of the body.
Important: Even though genital warts may be emotionally disturbing, they do not turn into cancer.
There are 14 high-risk HPV types that are associated with cancers in humans. HPV 16 causes most cases of cancers of the cervix, anus, penis, vagina, vulva, head and neck and esophagus. Together, HPV 16 and 18 cause about 70% of all the cervical cancers.
A HIDDEN THREAT
Infections due to cancer-causing strains of HPV usually go undetected because they do not cause warts or any other signs or symptoms.
Both women and men who are infected can unknowingly transmit the virus—usually during sexual encounters (vaginal, anal or oral sex). The virus enters the body through cuts or tiny tears in the outer layer of the skin in the vagina, cervix, penis, anus and mouth. Because HPV is spread through skin-to-skin contact, it’s possible that skin-to-skin kissing (not saliva transmission) leads to head and neck cancers and that oral sex leads to esophageal cancer.
The good news is that the body’s immune system effectively eliminates the cancer-causing virus in about 90% of HPV infections—usually within two years. When the virus stays in the body beyond two years, it is considered persistent and the risk for cancer of the genitals, cervix, anus or oral cavity rises.
ARE YOU AT RISK?
Most HPV infections are transmitted through sexual activity, but about 10% to 15% of the population become infected via nonsexual sources that have not yet been identified. In general, the risk for HPV infection is higher for people with impaired immunity—for example, anyone undergoing chemotherapy or those with diabetes or an autoimmune disease, such as lupus or rheumatoid arthritis, and for people who have many sexual partners or who use devices that cause tears (even very tiny ones) in the skin of the genitals, anus or mouth.
A common ingredient in many vaginal spermicides, nonoxynol-9, triples a woman’s risk for HPV infection. It damages the lining of the vagina and makes it easier for the virus to enter through the skin.
TESTING AND DIAGNOSIS
For decades, the Pap test has been used to detect precancerous changes to cells in the cervix. If a woman’s Pap results were described as atypical, she was advised to undergo a test that checks for one or more of 14 cancer-causing HPV types.
The US Preventive Services Task Force recently released guidelines that reversed this course. Now women 21-to-29 years old are screened every three years with a Pap test alone, but those 30-to-65 years old can get the HPV test to screen for cervical cancer. If the test is positive, then a Pap test is done. If the test is negative, a woman can safely wait five years to be screened again. The two older options for Pap testing every three years or co-testing with both the HPV test and the Pap test are also valid ways to screen.
THE HPV VACCINE
Gardasil9 has replaced the original Gardasil vaccine. It prevents infection from seven of the 14 high-risk strains of HPV associated with cancer (the original protected against just two, HPV 16 and HPV 18). It was recently approved by the FDA for men and women up to age 45.
How it’s used: The Centers for Disease Control and Prevention (CDC) recommends two doses given six to 12 months apart for young people getting the vaccine before their 15th birthday and three doses for everyone over age 15 with the second dose given one to two months after the first dose and the third dose six months after the first dose.
Safety profile: A controversial 2006 report published in JAMA found some serious adverse effects, including death, after Gardasil use. However, repeated studies done in the US and internationally since then and reviewed by the World Health Organization have found it safe. It is not yet known if it poses any risks to women given the vaccine while pregnant. Discuss the risks and benefits of the vaccine with your physician.
OTHER PREVENTIVE STEPS
Using a condom reduces—but does not eliminate—risk for HPV infection in women and men. This is because the virus can occur in areas that aren’t covered by a condom, and it can be spread by hand-to-mouth contact. Being in a mutually monogamous relationship with someone who has had few or no previous partners also curbs risk.
Women who use spermicides that contain nonoxynol-9 (including male condoms that use this ingredient) to prevent pregnancy should consider switching from this form of birth control to some other method, such as oral contraceptives or cervical caps. Both men and women should ask for an oral cancer check during each dental visit. And men should regularly check for signs of penile cancer, such as visible bumps or ulcers.