oral HPV in men and oropharyngeal cancer

Just as I sent out the last HPV blog (see http://gmodestmedblogs.blogspot.com/2017/10/primary-cervical-hpv-screening-and.html ,which argues for primary HPV cervical screening in women, and notes the  dramatic 97% efficacy of the 9-valent HPV vaccine), this article appeared showing very high rates (12%) of men are infected with oral HPV (see doi:10.7326/M17-1363), a study sponsored by the National Cancer Institute.

Details:

--Population: Adults aged 18-69 from the 2011-2014 NHANES (National Health and Nutritional Examination Survey), self-reported data from 4493 men and 4641 women

Results:

--Overall prevalence of oral HPV infection was 11.5% in men and 3.2% in women, suggesting infection in 11 million men and 3.2 million women in the US

--High-risk oral HPV infection was found in 7.3% of men and 1.4% of women, which translates to 7 million men and 1.4 million women

    ​--Oral HPV-16 infection, the type conferring the highest oropharyngeal cancer risk, was found in 1.8% of men and 0.3% of women, 6x more frequent in men, which translates​ to 1.7 million men and 0.27 million women

--Age-distribution:

    --men: highest HPV prevalence was age 50-54 (15.4% overall, 9.9% high risk HPV), increasing from age 18-26 (6.8%, 5.0% high risk), then to 10.6% (7.0% high risk) age 27-34, and plateauing at high levels from age 45-60. the only statistically significant change was the increase in the 35-39 age group from the earlier ages. HPV-16 was most prevalent in  men aged 50-69.

    --women: highest HPV prevalence was age 50-54 (3.8% overall, 2.3% high risk HPV), but was pretty equal for the different age groups and not statistically significantly different by age group

--in men and women with same-sex oral sex partners, the prevalence of high-risk HPV infection was 12.7% in men and 3.6% in women

    ​--in men with 2 or more lifetime same-sex oral partners, the prevalence of high-risk HPV infection was 22.2%

--oral HPV prevalence was higher in men who had concurrent genital HPV infection (19.3% vs 4.4% without genital infection) [this has been found in other studies as well, and to some extent might reflect autoinoculation, through fingers in the same individual]

--the highest incidence of high-risk oral HPV infection was among black participants (15.8% overall, 8.8% high-risk), those smoking >20 cigarettes/d (23.6% overall, 15.0% high-risk), marijuana users (13.4% overall, 9.4% high-risk)​, and those with >15 lifetime vaginal or oral sex partners (20.8% overall, 14.2% high-risk).

--there was no oral HPV prevalence difference in those who had received the HPV vaccine, but the numbers were small (18 cases in 135 men). And, even then the prevalence of the 4-valent types in the vaccine (which included type 16) was significantly lower in men (0.41% vs 1.97%, p=0.019). also was significantly lower for women

Commentary:

--from 2008-2012, there was an annual average of 38,793 HPV-related cancers in the US (oropharynx, anus, penis in men; oropharynx, anus, cervix, vagina and vulva in women), 23,000 in women and 15,793 in men. The most common one was oropharyngeal  squamous cell carcinoma (OPSCC)​, with 3100 cases in women and 12,638 in men

-- OPSCC is broadly classified as either HPV or non-HPV-associated (70% appear to be HPV-associated). the non-HPV-associated laryngeal, hypopharyngeal and oral cavity cancers have been decreasing, paralleling the decline in cigarette smoking.  The oropharyngeal cancers most commonly associated with HPV infection are in the base of the tongue and tonsillar region

-OPSCC incidence has been stable in women  from 2002-2012, but has increased dramatically in men: 7.8/100K, but increasing at 2.89%/yr), and the increase has been particularly high in men aged 50-59

--at this time, the incidence of OPSCC in men (from CDC: 2009-2013, highest in white men at 8.2/100K, lower in Hispanic men at 4.3/100K) surpasses that of cervical cancer in women (7.4/100K, with 7.0/100K in white women, 9.0/100K in black women and 9.3/100K in Hispanic women)

--HPV-16 in the type most clearly associated with oropharyngeal cancers, and HPV vaccination has been associated with a decrease in subsequent high-risk oral HPV infections (including HPV-16)

--HPV persistence seems to increase in age, so it is not surprising that the prevalence curve is shifted to older people. It would be useful to have data collected over time to see the relative contributions of persisting vs new infections. But it is pretty striking in men that the younger group (<35yo) did have a much lower incidence of both HSV and high-risk HSV, suggesting that many new infections likely occurred in middle-aged and older men

--however, current guidelines promote HPV vaccination of females up til age 26 and males up til age 21 unless they are higher risk (eg MSM, immunocompromised), but this increasing incidence of HPV infection and especially high-risk infection in older people suggests to me that we should significantly broaden this time range (instead of actually having a shorter one for men....)

so, this study reinforces the importance of HPV vaccination, with increased efforts to reach out to males (who had a complete HPV vaccination rate in adolescents of only 28.1% in 2015, vs 41.9% in females). it also raises the issue that we should probably be vaccinating beyond the current suggested (and reimbursed) timeframe of females up til age 26 and lower-risk males up til age 21 …