More than 33,000 cancers associated with human papillomavirus (HPV) were detected in U.S. men and women, on average, each year between 2004 and 2008; many such cases are preventable through the use of vaccines, cervical cancer screening and follow‐up, and safer‐sexual practices.1 (HPV‐associated cancers are defined by their location and by the presence of cell types in which HPV DNA is often found.) Cervical cancer was the most commonly diagnosed HPV‐associated cancer, occurring at a rate of 7.7 cases per 100,000 population; an estimated 96% of cases resulted from HPV infection.
To assess the burden of invasive HPV‐associated cancers, analysts from the Centers for Disease Control and Prevention gathered data from two population‐based cancer registries, the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results Program. Six types of cancer were defined as being HPV‐associated—cervical carcinomas; and vulvar, vaginal, penile, anal and oropharyngeal squamous cell carcinomas. The analysts used published data on the proportion of HPV‐associated cancers that result from infection with the virus to estimate the annual number of cancers that were HPV‐attributable.
Overall, 33,369 HPV‐associated cancers were diagnosed annually in 2004–2008, for a rate of 10.8 per 100,000 population. Women accounted for 21,290 diagnoses annually, and men for 12,080; corresponding rates were 13.2 and 8.1 per 100,000, respectively. The greatest annual number of diagnoses (nearly 12,000) was of cervical cancer, which occurred at a rate of 7.7 per 100,000; more than 9,000 cases of oropharyngeal cancer were detected each year among men, resulting in a rate of 6.2 per 100,000. Vaginal and penile cancers occurred at rates of less than 1.0 per 100,000; the remaining HPV‐associated cancers, at rates of 1.2–1.8 per 100,000.
A number of significant differences in rates were apparent by race and ethnicity. Notably, blacks had higher rates of cervical, vaginal and penile cancer than whites; the reverse was true, however, for vulvar cancer. Similarly, anal cancer was more common among black men than among whites, but it occurred at a higher rate among white women than among blacks. Hispanics had higher rates of cervical and penile cancer, but lower rates of all other HPV‐associated cancers, than non‐Hispanics.
Rates also differed by location. Utah registered the lowest overall rate of HPV‐associated cancers for both men and women; the District of Columbia had the highest rate among males, and West Virginia the highest among females. Geographic patterns of cancer‐specific rates varied.
The analysts estimate that 26,000 cancers detected each year (18,000 among women and 8,000 among men) resulted from HPV infection. These include 96% of cervical cancers, 93% of anal cancers, 63–64% of vaginal and oropharyngeal cancers, 51% of vulvar cancers and 36% of penile cancers.
Noting that HPV 16, one of the strains that can be prevented by available vaccines, is "responsible for the majority of noncervical cancers caused by HPV," the analysts reason that vaccination might be effective in preventing other HPV‐associated cancers. Additionally, they point out that variations in cancer rates may result from differences in factors not included in the available data—for example, screening practices and risky behaviors. They conclude that "ongoing surveillance … using high‐quality population‐based registries is needed to monitor trends in cancer incidence that might result from increasing use of HPV vaccines, changes in cervical cancer screening practices, and changes in behaviors that increase risk for HPV infection, persistence, or progression.—D. Hollander