The media recently gave widespread exposure to an interview, originally published in a British newspaper, in which actor Michael Douglas speculated that his throat cancer may have been caused by a human papillomavirus (HPV), which is transmitted through oral sex.
“That story sparked national awareness and far more conversation than we have ever had about the link between sexually transmitted viruses and some cancers,” says Michael Kosty, MD, medical director of cancer care at Scripps Clinic and Scripps Green Hospital.
That conversation is timely. HPV is the most common sexually transmitted infection in America. There are more than 150 related viruses. About 40 can be easily spread through skin-to-skin contact during oral, anal or vaginal sex. According to the Centers for Disease Control and Prevention (CDC), nearly all sexually active men and women will get HPV at some point in their lifetime. Most (90 percent) clear the infections on their own; but a small fraction will lead to cancer.
Two strains — HPV 16 and 18 — are responsible for 85 percent of all anal cancer, 70 percent of all cervical cancer cases and nearly half of vaginal, vulvar and penile cancers. Most recently, HPV infections were linked to cancer of the oropharynx, which includes the middle part of the throat, base of the tongue, soft palate and tonsils. Rates of throat cancer have soared in the last few decades — especially among men. Now, about 70 percent of oropharyngeal cancers are caused by viruses transmitted by sex.
To combat cancer, there are two HPV vaccines. The Food and Drug Administration (FDA) approved Cervarix for the prevention of cervical cancer; and Gardasil for the prevention of cervical, anal, vulvar and vaginal cancer. Both guard against high-risk HPV 16 and 18. A new study released in July of 2013 provided evidence that Cervarix provides protection against throat cancers caused by HPV.
“With more widespread adoption of these vaccines, we also expect to see fewer HPV-associated oral cancers in the decades to come,” says Dr. Kosty.
Gardasil and Cervarix are most effective if they are administered in three separate doses — several months apart — before a person becomes sexually active. The CDC recommends vaccination for girls and boys at age 11 or 12.
It is important to note that, while condoms may help to prevent some HPV infections, the virus may still be transmitted by skin-to-skin contact in areas not covered by the condom. While only abstinence is 100 percent certain to prevent infection, Gardasil and Cervarix offer more protection than condoms. Gardasil also prevents genital warts cause by HPV.
According to the most recently available data from CDC, the rate of HPV infection in girls and young women has dropped 56 percent in the seven years since Gardasil was introduced — despite low rates of inoculation. Only one third of girls in the U.S. receive the recommended three doses by the age of 17.
Some moms and dads may be concerned that the HPV vaccine could be perceived as a license to become sexually active. Research suggests that is not the case. A study published in 2012 found no correlation between receiving HPV vaccination and later sexual activity.
“I would advise parents to be proactive by having open dialogue about the vaccine with their child’s pediatrician,” says Dr. Kosty. “Conversations about a child’s sexual and reproductive health may be difficult, but taking advantage of vaccines that prevent some cancers may be a good reason to begin those conversations.”