While cruising through the Medscape Pathology and Lab Medicine web site (you need to register, but it's free). I came across some recent clinical studies on HPV in ENT carcinomas. The most recent one
, is a large series (n=1606) of patients from Denmark treated with radiation therapy for advanced stage squamous cell carcinoma of the head and neck. HPV/p16 status was assessed. For patients with oropharyngeal carcinomas, HPV status, as shown by others, was a significant prognostic factor. HPV/p16+ tumors had significantly better locoregional control and 5-year disease-free survivals when compared to HPV/p16- patients. However, for other anatomic sites in the ENT region, such as the larynx, the HPV/p16 status did not affect prognosis.
This is an interesting and unexpected finding that needs verification in other studies. Of course, outside of the oropharynx, only a small minority of ENT squamous cell carcinomas is related to HPV, in contrast to the high percentage of HPV+ oropharyngeal cases. We also know that HPV status does not appear to affect the prognosis of HPV-associated non-squamous carcinomas in this region, including neuroendocrine carcinomas and adenocarcinomas. However, the numbers of such cases are quite small and further study is clearly needed.
The second and slightly older article in Medscape
is a summary of a Lancet article
from July 2013 examining the epidemiology of oral HPV infections in men. The study followed 1626 men between the ages of 18 & 73 years. The cohort was from Brazil, Mexico, and the United States. Median follow-up was slightly over one year. During this time, 4.4% of the cohort developed an incidental oral HPV infection. 1.7% of these were with high-risk (oncogenic) HPV subtypes, mainly HPV-16 (0.6%). Most of the infections appeared to be cleared in one year. The method of detection was by oral rinse and gargle, which may have significantly underestimated infection rates. There was a significant association between martial status and the risk of acquiring any oncogenic HPV infection. Men who were married or cohabiting were at significantly lower risk than men who were single, divorced, separated, or widowed. ""Marital status seems to be more predictive of oral HPV acquisition than does lifetime number of sexual partners," the authors report. However, these findings are in contrast with those from some previous studies, which found an association with the number of lifetime and recent partners, they note. Smoking also appeared to increase the risk of infection.
It is clear that the rate of HPV-related oropharyngeal carcinoma has increased dramatically in the last decade. In fact, invasive HPV-related oropharyngeal carcinomas currently outnumber invasive uterine cervical carcinomas. Epidemiologists continue to be perplexed by this dramatic rise. Although there is some correlation, as shown above, with number of sexual partners, studies regarding specific sexual habits (oral sex rates) have shown inconsistent results. In short, there is no evidence that there has been any dramatic change in sexual practices in the last few decades (hardly surprising!) to account for this dramatic increase in HPV-related oropharyngeal carcinomas.