Prevalent oral HPV16 infections were more likely to persist in men older than 45 years, according to results.
Although HPV-positive oropharyngeal cancers are still considered rare in the United States, incidence in men has increased significantly in recent decades, and annual cases of HPV-positive oropharyngeal cancers have surpassed cases of cervical cancer, according to background information in the study.
Christine M. Pierce Campbell
“Mounting evidence in some economically developed countries suggests that human papillomaviruses cause the majority of oropharyngeal cancers among men, with HPV type 16 implicated in most cases,” Christine M. Pierce Campbell, PhD, MPH, assistant member in the department of cancer epidemiology and Center for Infection Research in Cancer at Moffitt Cancer Center, and colleagues wrote.
Pierce Campbell and colleagues evaluated oral samples from 1,626 men enrolled in the HPV Infection in Men (HIM) Study, an ongoing, multinational cohort study assessing the natural history of genital HPV infections in men. None of the participants reported cases of head or neck cancers at the time of enrollment.
Researchers collected oral samples from participants at the time of enrollment, then every 6 months thereafter for up to 4 years. Using robotic DNA extraction, investigators tested the oral samples for presence of HPV DNA and used the Linear Array (Roche Molecular Diagnostics) test to conduct HPV genotyping.
Participants also completed computer-assisted self-interviews with questions that addressed sociodemographic characteristics and potential risk factors.
During the study period, HPV16 was detected in two or more oral samples from 23 of the study participants. Of these 23 men, 10 had prevalent infections — meaning they were present in the sample collected at enrollment — and 13 had incident infections, which rose during the study period.
Of the 10 men with prevalent infections, nine persisted more than 1 year, eight persisted more than 2 years, four persisted more than 3 years and two persisted more than 4 years. Median infection duration was not available for prevalent infections.
Of the 13 men who acquired incident infections during the study, four persisted more than 1 year, one persisted more than 2 years and none persisted more than 3 years. Median infection duration was 7.3 months.
Investigators used the Kaplan-Meier method to determine that the cumulative probability of continued infection among men with prevalent oral HPV16 was consistently higher than the cumulative probability of continued infection among men with incident infection throughout the follow-up period (P=.014).
The proportion of incident infections that persisted for at least 12 months increased significantly with age (P=.028), according to study results. All men aged at least 45 years had persistent HPV infection, compared with 50% of men aged 31 to 44 years. None of the men aged 18 to 30 years had persistent HPV infection.
Twelve-month persistence of prevalent infections also was higher among older men, but the difference was not statistically significant.
“These findings may explain the high prevalence of HPV16 persistence observed at older ages,” Campbell and colleagues wrote. “Understanding oral HPV16 persistence will aid in the identification of men at high-risk of developing HPV-related oropharyngeal cancer.”
Disclosure: One of the researchers reports receiving speakers’ bureau honoraria from Merck Sharp & Dohme, as well as a consultant/advisory board role with Merck Sharp & Dohme and BD Technologies.