There is one large caveat to this dream of a healthier tomorrow. There are some 20 different HPV strains that can lead to cancer, and while current vaccines prevent the ones that cause 70 percent of all cervical and the majority of oropharyngeal cancers, they're not completely comprehensive. (To make a vaccine effective for all strains of HPV—including the 100 or so that don't cause cancer but may cause warts and other skin problems—you'd need a syringe the size of a milk carton.) So parents should know that getting their sons and daughters these shots won't guarantee that they willnever develop HPV-related cancers.
But even with this limitation, the potential benefit of the vaccine is quite large. Cervical cancer is the most common cause of cancer death in women in many developing countries; in the United States, Pap smears and early treatment have sharply reduced the impact, though it still affects 12,000 women a year and kills 4,000 (PDF). Meanwhile, head and neck cancer is diagnosed in 36,000 people (mostly men), killing 8,000, making it the eighth-most-common cancer for men—a figure that will continue to rise as the impact of HPV infection is manifest. Indeed, the NCI researchers projected that, given the current increase in cases, HPV-related oropharyngeal cancers would be more common than cervical cancer by the year 2020.
If the past is any indication, though, I suspect a more eyebrow-raising angle will overshadow this important public health story. Since the link between HPV and oral cancer was first floated 10 years ago, the media has tended to focus on just one aspect—the possible connection between oral sex and the rise in oropharyngeal cancers. However, there's no definitive evidence yet of a causal relationship between the activity and the disease. That's not to say that people shouldn't exercise a reasonable amount of caution when having oral sex. But when popular opinion (particularly in matters sexual), wags science, no one benefits.
It's easy to see why the notion that oral sex can give you cancer is so attractive. It makes for an irresistibly lurid headline, of course, and it appeals to the secret Victorian hidden less or more deeply in all of us. (Everything fun has a price—everything!) And to be fair, the circumstantial evidence is compelling. It's well understood that HPV is transmitted through other kinds of intimate contact, such as vaginal sex. HPV seems to grow quite well on mucous membranes, those nonskin tissues that line the mouth, nose, vagina, anus, and a few other anatomic areas, and which may touch quite a bit during oral sex.
As an explanation for the uptick in oropharyngeal cancers, though, oral sex has one glaring problem: HPV-positive head and neck cancer is, inexplicably, a guy's disease. If oral sex were driving the issue, wouldn't we see a commensurate rise in HPV-positive tumors among women? Unless the announcement was screened out by my workplace email filter, I don't think anyone has demonstrated that cunnilingus is being practiced more often than fellatio.
Furthermore, many people with HPV-positive head and neck tumors deny having had much oral sex. According to a 2010 review of several studies on the topic, more than half of such patients reported five or fewer lifetime oral sex partners, and 8 to 40 percent said they had never had oral sex.
Finally, the argument that oral sex is driving the rise in these cancers carries the implicit suggestion that oral sex patterns of recent years vary considerably from previous generations. Among the many things we don't know about our forebears, what they did and didn't do in the bedroom surely ranks near the top. And it always is a bad wager to bet against the likelihood that everyone, in every decade, was having all types of sex, and as often as possible.
To be fair, the oral sex angle does make one important contribution to the efforts to control HPV: It gets people's attention. As the titillated masses wait for the truth to emerge, here's hoping they do the right thing—and take their kids to the corner pediatrician to get vaccinated.