September is sexual health awareness month. In recognition, enjoy a previous post by Dr McGlennen regarding oral health and sexual health.
It is important to understand the role of human papillomavirus (HPV) in the development of squamous cancers of the head and neck. But it seems there is missing a fuller appreciation of other key risk factors at work with the virus, to cause bad things to happen to cells in the mouth and throat. HPV infection is very common, and with the sensitive molecular techniques available in the clinical laboratory, its now been proved that upwards of 5-10% of adults have oral HPV infections. That’s a large number of people. But clearly not each of those infected should worry about getting oral or pharyngeal cancers. What are the other things that impart risk that might help us connect the dots to identify those persons more truly at risk?
Recent research points to a role for chronic inflammation to be a critical effector to make oral HPV infections worse, and at risk to transform into malignancies. Inflammation plays a causal part in cancers of the lung, stomach, pancreas and colon, it follows that inflammation may be important in the head and neck as well. A review article by Mine Tezal from the Department of Oral Diagnostic Sciences at State University of New York, Buffalo underscores that, in the majority of instances, the source of chronic inflammation is periodontitis. Whether due wholly to the presence of select bacteria and in combination with a person’s inherited proclivity to have inflamed gums, persons who are coincidently infected with HPV, have a multi-fold greater risk of developing oral cancers, than those without periodontitis. Specifically, patients showing apical bone loss (ABL), a hallmark of periodontitis, are up to 4 times more likely to harbor HPV in “dysplastic” epithelium, and that HPV infection is more likely to “persist”, a verifiable risk factor for cancer when a patient tests positive for HPV repeatedly over time, usually about 1-2 years.
So, it is likely that chronic inflammation, gum disease and oral cancer are connected. Most of what we know about the role of oral HPV and the development of squamous cell cancers of the head and neck are retrospective. That is to say, there is scant little study on the prevention of this disease, which increasingly, is one afflicting younger people, even in the face of efforts to reduce smoking and chronic alcohol use, two classic risk factors for these cancers, but versions of which occur mostly in older patients. One approach to prevention, however, is to test patients: both for HPV and for markers of periodontitis. Finding infections early, including both HPV and periodontal bacteria, and then working to help patients reduce inflammation (which includes simple things like using aspirin and other NSAIDs) is a strategy to prevent disease, and probably would apply to half the adult patients you’ll see today.
Tezal, M. Interaction between chronic inflammation and oral HPV infection in the etiology of head and neck cancers. Int. J of Otolaryn v 2012, pp. 1-9, 2012.