In 2015, oropharyngeal squamous cell carcinoma surpassed cervical cancer as the most common HPV-associated cancer in the U.S., with 15,479 cases among men and 3,438 cases among women, according to data from the CDC published in Morbidity and Mortality Weekly Report.

The report also showed that rates of HPV-related anal squamous cell carcinoma and vulvar cancer increased over the past 15 years, whereas rates of HPV-related cervical cancer and vaginal squamous cell carcinoma decreased.

“Although smoking is a risk factor for oropharyngeal cancers, smoking rates have been declining in the United States, and studies have indicated that the increase in oropharyngeal cancer is attributable to HPV,” Elizabeth A. Van Dyne, MD, epidemic intelligence services officer in division of cancer prevention and control at the National Center for Chronic Disease Prevention and Health Promotion of the CDC, and colleagues wrote.

“In contrast to cervical cancer, there currently is no U.S. Preventive Services Task Force recommended screening for other HPV-associated cancers,” they added.

The trends in HPV-related cancers report included data from 1999 to 2015 from cancer registries — CDC’s National Program of Cancer Registries and NCI’s SEER program — covering 97.8% of the U.S. population.

The CDC reported 30,115 new cases of HPV-associated cancers in 1999 compared with 43,371 new cases in 2015.

During the study period, researchers observed a 2.7% increase in rates of oropharyngeal squamous cell carcinoma among men and a 0.8% increase among women. Rates of anal squamous cell carcinoma increased by 2.1% among men and 2.9% among women.

Among women, researchers observed a 1.6% decrease in HPV-related cervical cancer and a 0.6% decrease in rates of HPV-related vaginal squamous cell carcinoma. Rates of vulvar squamous cell carcinoma increased by 1.3%.

Rates of penile squamous cell carcinoma remained stable from 1999 to 2015.

Overall, rates of HPV-related cancers varied by age and race/ethnicity.

Researchers observed a 4% increase in the rate of oropharyngeal squamous cell carcinoma among men aged 60 to 69 years compared with a 0.8% increase among men aged 40 to 49 years.

For anal squamous cell carcinoma, the largest increases occurred among women aged 50 to 69 years (4.6% to 4.8%) and men aged 50 to 59 years (4%).

Several factors contribute to the increased incidence of oropharyngeal and anal squamous cell carcinomas, including changes in sexual behavior.

“Unprotected oral sex and receptive anal sex are risk factors for HPV infection,” the researchers wrote. “White men have the highest number of lifetime oral sex partners and report first performing oral sex at a younger age compared with other racial/ethnic groups; these risk factors could be contributing to a higher rate of oropharyngeal squamous cell carcinoma among white men than other racial/ethnic groups.”

Cervical cancer rates remained stable among women aged 35 to 39 years; however, younger and older woman demonstrated decreases ranging from 1.2% to 4.2%.

Cervical carcinoma rates decreased across all racial/ethnic groups, although decreases appeared more prominent among Hispanics than non-Hispanics (3.4% vs. 1.5%).

“The decline in cervical cancer from 1999 to 2015 represents a continued trend since the 1950s as a result of cancer screening,” the researchers wrote. “Rates of cervical carcinoma in this report decreased more among Hispanics, American Indian/Alaska Natives and blacks than other groups; however, incidence rates were still higher among Hispanics and blacks than among whites in 2015. These persistent disparities in incidence suggest that health care delivery needs of some groups are not fully met.”

The limitations of the report included the fact that the cancer registries do not routinely determine the HPV status of cancers and that race/ethnicity data was derived from medical records.

“Further research to understand the progression from HPV infection to oropharyngeal cancer would be beneficial,” the researchers wrote. “Continued surveillance through high-quality registries is important to monitor changes in HPV-associated cancer incidence.” – by Cassie Homer