Wednesday, March 9, 2016

Human Papillomaviruses (HPVs) Cause Mouth, Throat & Voicebox Cancers

I noted four years ago that “there is emerging scientific evidence that human papillomaviruses (HPVs), which are recognized to cause cervical cancer in women, may cause oral cancer.”  Now, JAMA Oncology (abstract here) reports the first epidemiologic study showing that several HPVs may increase mouth, throat and voicebox cancers. 

Lead author Ilir Agalliu writes that after researchers detected HPVs in mouthwash samples from nearly 100,000 participants age 50+ years in two large studies, participants were followed for about four years.  During that time, 132 subjects developed squamous cell cancers; about 40% of those tumors were in the voicebox, 35% in the mouth and 25% in the throat.  Agalliu compared the HPV profile in those cases with controls who were carefully matched for age, sex and race.  The results were adjusted for smoking and alcohol use, known risk factors for these cancers.  In this study, only 14% of subjects had never smoked, compared with 46% in the control group.

HPV-16, which spreads via sexual contact and is a major risk factor for cervical cancer, in this study was associated with throat cancer (odds ratio, OR = 22), but it was not a risk for mouth or voicebox cancer.  Because the throat cancer finding was based on only five cases, the association needs to be confirmed by additional research.  Other HPV types were linked to mouth and voicebox cancers, but again the number of cases was small.  While at least 170 different HPVs have been identified, experts believe there may be 200 additional types.    

There is now clear and compelling data about the most important risk factors for mouth and throat cancer: (1) Smoking and/or heavy alcohol consumption, and (2) sexually transmitted human papillomaviruses.  Dozens of other studies provide equally clear and compelling evidence that smokeless tobacco use is NOT a significant risk factor for these cancer types (here).

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