Record rate of HPV-related throat cancer

 

Have you read the headlines that the incidence of oropharyngeal cancer in men has outpaced the incidence of cervical cancer in women? Further, that the prevalence of oropharyngeal cancer in men has doubled over the past 20 years? All true. But the headlines make the situation appear more dire than it currently is. However, without action, the situation could eventually become a dire public health threat. There is an important role for women’s reproductive health providers to play in containing the threat of an epidemic of HPV-related throat cancer.

The incidence of oropharyngeal squamous cell carcinoma  (OPSCC) associated with human papillomavirus in men is now 7.8 per 100,000.[1] That compares to the 7.4/100,000 incidence of cervical cancer in women.[2] Obviously the first number, for men, is higher than the second number for women. However, keep in mind that the incidence of OPSCC in men is much lower than that for prostate cancer (96/100,000).[3] It’s lower than the incidence in women of ovarian cancer (12/100,000), uterine cancer (26/100,000), and breast cancer (124/100,000).

So why the heightened concern? Because the prevalence has indeed doubled over the past two decades, and researchers expect that trend will likely continue to the year 2060. They base their prediction on the high rate of oral HPV infection in men. HPV infection raises the risk for OPSCC by 7-fold. In a recent study published in the Annals of Internal Medicine, researchers reported that 11.5% of men in the NHANES (National Health and Nutritional Examination Survey) had oral HPV infection.[4] High-risk oral HPV was detected in 7.3% of men in the survey. The respondents, aged 18 to 69 years and identified through a stratified, multistage probability sampling technique, provided specimens by oral rinse and penile swab. They underwent medical examination by a mobile examination center and interviewed in person or by phone.

Certain risk factors increased substantially the prevalence of oral HPV infection in men:

• 16 or more lifetime oral and vaginal sex partners, especially oral sex
• 2 or more same-sex oral sex partners (but not anal sex)
• Smoking >20 cigarettes/day
• Concurrent genital HPV infection
• Current marijuana smoking

Smoking is thought to be a risk factor because it is proinflammatory and immunosuppressive. That concurrent genital infection with HPV increases a man’s risk by a factor of 4 suggests a potential element of autoinoculation.

It is the prevalence of oral HPV infection that indicates that the incidence of OPSCC in men will continue to increase for decades to come. Boys are woefully under-immunized against HPV. Despite a recent surge in the numbers of those who have received at least one dose of the vaccine, only 31% of boys have completed all three doses.[5]

So here is where women’s health providers can step in, by encouraging mothers to have their sons vaccinated and by educating young adult women patients about the HPV vaccine, not only for themselves, but for the guys in their lives, too. The HPV vaccine seems to protect against oral subtypes as well as genital ones; in the NHANES study, participants who had been vaccinated had a several times lower prevalence of oral HPV infection. There is no approved screening test to detect HPV-related OPSCC in its early stages.

What about the picture for women? They have significantly lower risks of HPV oral infection: 3.2% overall and 1.4% for high-risk strains. However women who smoked marijuana had an infection prevalence of 7.9%. The same risk factors, mentioned above, that increased the prevalence of oral HPV infection among men was similar for women; however, the increases in women were generally not statistically significant.

[1] Mourad M, et al. epidemiological trends of head and neck cancer in the United States: a SEER population st;udy. J Oral Maxillofac Ssurg 2017; DOI: http://dx.doi.org/10.1016/j.joms.2017.05.008

[2] Centers for Disease Control and Prevention. Vital signs: cervical cncer incidence, mortality,and screening—United States 2007-2014. MMWR 2014;63:1-6.

[3] Centers for Disease Control and Prevention. Unisted States Cancer Statistics: 2014 top ten cancers. Table 4.1. At https://nccd.cdc.gov/uscs/toptencancers.aspx. Accessed Nov. 6, 2017.

[4] SonawaneK, et al. oral human papillomavirus infection: differences in prevalence between sexes and concordance with genital human papillomavirus infection, NHANES 2011 to 2014. Ann Intern Med 2017;doi:10.7326/M17.1363

[5] Centers for Disease Control and Prevention. National, regional, states, selected local area vaccination coverage among adolescents aged 13-17 years—United States. MMWR 2017;66:874-882.