When It Comes to Cancer, Oral Sex May Not Always Be Safe Sex

The number of oral cancers resulting from HPV infections is on the rise.


Oral sex can’t lead to pregnancy.  That’s why so many people consider oral sex to be “safe sex.”  This is a driving factor in for the almost 50% of all American teenagers who have oral sexual relations.  And, of course, oral sex is common among adults as well.

Don’t get me wrong.  I am not anti-oral sex (believe me!).  Nor am I preaching oral sex abstinence (absolutely not!).  What you do as a consenting adult is between you and your consenting adult partner.

  I am serving in the role of objective physician partner.  And from the perspective of the objective physician partner, it is important that you appreciate that for some, oral sex is not completely “safe sex.”

Michael Douglas has perhaps done more to raise awareness of the risk of oral sex than any other person.  Most importantly, the actor’s openness reminded people of an important fact:  oral cancer can be triggered by an oral sexually transmitted infection.

Now, the one cancer that many women appreciate can result from infection is cancer of the cervix.  The reality is that almost all cervical cancers, about 99%, result from a sexually transmitted infection of the tissue lining of the cervix by a virus called HPV (human papilloma virus).  While much like the seasonal flu virus, there are many, many different types (strains) of HPV (as many as 200), only a handful of HPV strains are linked to an increased risk of cervical cancer.

  And, fortunately, there the FDA has approved vaccines which can prevent infection with the HPV strains associated with the development of cervical cancer.

So yes, HPV infection can lead to cervical cancer.  And as Michael Douglas explained, cancer of the oropharynx (the back of the tongue, the back and sides of the throat, the soft palate, and the tonsils) can also result from an HPV infection.

  And an oropharyngeal HPV infection can result from oral sex (both heterosexual and homosexual, and both oral-genital and oral-anal).

Here’s the stunning bad news statistic:  as many as 80% of sexually active adults will be infected with HPV at least once during our lifetimes.  And here’s the stunning good news statistic:  the body eventually is able to clear the infection in approximately 99% of infected individuals (although it may take years). 

Given how overwhelmingly common HPV is and that about 1% of infections are persistent, and appreciating the prevalence of oral sex among teens and adults, it is not surprising that the incidence of HPV-related oropharyngeal cancer is rising rapidly.  By 2020, it is projected that the number of people who developed an HPV-related oropharynx cancer will exceed the number who are diagnosed with cervical cancer.

Not every person who has an oral sexual encounter is at equal risk of ultimately developing an oropharyngeal cancer.  Studies suggest that the likelihood of developing an HPV infection-related oropharyngeal cancer is significantly greater if you have had six or more oral sex partners (similar to many other sexually transmitted diseases, where number of partners is a major risk factor for infection).

  And smoking and alcohol use, both known non-HPV-associated oral cancer risk factors, may increase the likelihood of cancer in a person infected with a high risk HPV strain, although the evidence is still unclear.  As for who is at greater risk, HPV-associated oropharyngeal cancers are more common in Caucasians, in men, and in adults age 33 to 44 years.  But that doesn’t mean that non-whites, women, and middle age and older adults are not at risk; rather, they are at lower risk but still may develop HPV infection-associated oropharyngeal cancer (especially if they have had multiple oral sexual partners). Finally, the risk of infection and subsequent cancer development is increased in individuals who are immunosuppressed.

What about husbands and wives and monogamous partners of people with HPV-associated oropharyngeal cancers?  Are they at greater risk?  Should they no longer engage in oral sexual activities with their partner?  According to one pilot study, such monogamous partners are at no greater risk of developing HPV-associated oropharyngeal cancers, suggesting that special precautions (let alone avoidance of oral sexual intimacy) are not necessary.  That said, additional, larger clinical studies are still needed to determine if these pilot study results are correct.  And no doubt such partners should be regularly examined for suspicious growths during routine dental and/or physician physical examinations.

So what can you do to protect yourself from developing HPV-related oropharyngeal cancer?  You can avoid or certainly limit the number of oral sexual partners you have.  That said, for many, this “behavioral change” is not a choice they are willing to make.  The Food & Drug Administration (FDA) has approved a vaccine for the prevention of HPV-associated cervical cancer, and given that this vaccine prevents infection with HPV type 16, the viral strain most frequently implicated in the development of oropharyngeal cancer, many physicians believe the same vaccine will provide protection from future oral cancer development.  And early evidence is consistent with this belief, although more studies are needed to support any future FDA approval.

So while it’s true that you can’t get pregnant or impregnate someone through oral sex, now you know that “safe” is not completely “safe.”

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