According to a commentary published this week in the British Medical Journal (BMJ), despite a slight overall decrease in head and neck cancers worldwide, there has been a recent surge in one particular form of the disease—oropharyngeal squamous cell carcinoma—that may be due to the spread of the human papillomavirus (HPV) through oral sex. Dr. Hisham Mehanna, director of the Institute of Head and Neck Studies and Education at University Hospital in Coventry, as well as other cancer specialists, points to data showing that, in the U.S., there was little change in the incidence of this form of mouth cancer from 1975–1999, but between 1999 and 2006, cases of oropharyngeal squamous cell carcinoma grew by 22%. Among men in the U.K., there was a 51% increase in this form of mouth cancer between 1989 and 2006.
Researchers suggest that this growing form of mouth cancer is likely due to sexual transmission of HPV, pointing to data from a recent analysis of more than 11,0000 people showing that individuals with six or more sexual partners had a 25% higher risk for developing the disease. Additionally, the risk for this type of mouth cancer was nearly three times higher in individuals with four or more oral sex partners. As the authors sum up: “Sexual transmission of HPV—primarily through orogenital intercourse might be the reason for the increase in incidence of HPV related oropharyngeal carcinoma.”
Compared with other forms of mouth cancers—mostly caused by long-term tobacco and alcohol use—which often impact older patients and prove deadly within one to two years of diagnosis, if caught early, this HPV-related form of mouth cancer has significantly higher survival rates, especially among non-smokers. (The reasons for this difference aren’t entirely clear, but the researchers speculate that it may have to do with an increased immune response to HPV, or higher sensitivity to radiation therapy documented in previous study.)
Yet, even though the HPV-related form of mouth cancer tends to impact younger people and often has a better prognosis than other forms of the disease, researchers question whether public health initiatives currently cast a wide enough net to prevent its spread. A study published last fall in BMJ suggested that HPV vaccination for boys wasn’t cost-effective, or, as the researchers from the Harvard School of Public Health phrased it: “… including boys in an HPV vaccination programme [sic] generally exceeds conventional thresholds of good value for money.” Mehanna and colleagues question the findings of that study, writing that “the low incidence of HPV related oropharyngeal carcinoma in that study has led to concern because the recent rapid rise in HPV related oropharyngeal carcinoma may alter the cost effectiveness of vaccinating boys before they become sexually active.”
The next step in research is to determine how treatment of HPV-related oropharyngeal carcinoma may differ from treatments for other types of head and neck cancer, the authors conclude, suggesting that patients with HPV-related forms of the disease should be encouraged to enroll in clinical trials designed to improve treatment, and tailor it to this specific form of the disease.