CDC Report Underscores Need for HPV Vaccination

A decade after the FDA approved the first vaccine to prevent human papillomavirus (HPV), a new report from the Centers for Disease Control and Prevention (CDC) shows that the incidence of HPV-associated cancers is rising, with the number of HPV-associated cancers diagnosed annually between 2008 and 2012 increasing by approximately 16% compared with the previous 5-year period.

A decade after the FDA approved the first vaccine to prevent human papillomavirus (HPV), a new report from the Centers for Disease Control and Prevention (CDC) shows that the incidence of HPV-associated cancers is rising, with the number of HPV-associated cancers diagnosed annually between 2008 and 2012 increasing by approximately 16% compared with the previous 5-year period.

Nearly all sexually active individuals in the United States will get at least 1 type of HPV in their lifetime, making it the most common sexually-transmitted infection in the country. And though about 90% of HPV infections will clear a person’s system within 2 years, some infections persist and can cause cervical cancer and some types of vulvar, oropharyngeal, penile, rectal, and anal cancers.

There are over 40 HPV types, and vaccines are available for HPV types 16 and 18 (which account for 63% of HPV-associated cancers), as well as for types 31, 33, 45, 52 and 58 (which account for an additional 10%). Type 16 is the most likely to persist and develop into cancer.

In this new report, the CDC analyzed data from its own National Program of Cancer Registries as well as the National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) database. In total, 38,793 HPV-associated cancers (11.7 per 100,000 persons), on average, were diagnosed annually from 2008 to 2012 compared with 33,369 diagnoses (10.8 per 100,000 persons) from 2004 to 2008. Researchers then multiplied the number of cancers that could have been associated with HPV by the rate actually believed to be attributable to HPV, and found that an estimated 30,700 (79%) of the cancers could have been attributed to the virus.

Improving HPV Vaccination Rates

The CDC report highlights numerous challenges to controlling HPV-related cancers. First, not enough adolescents are receiving all 3 HPV vaccines. The CDC recommends that all males and females should start the HPV vaccine series at age 11 or 12. The CDC also notes that males can receive the series through age 21 and females through age 26.

However, according to this CDC report, in 2014, just 60% of females aged 13 to 17 received at least 1 dose, 50.3% at least 2 doses and 39.7% had the full 3-dose series. Among males, the rates were worse: 41.7% received at least 1 dose, 31.4% at least 2 doses and 21.6% 3 doses.

Additionally, differences exist between races. In the 2008-2012 study, rates of cervical cancer were higher among blacks compared with whites and higher among Hispanics compared with non-Hispanics. Rates of both vulvar and oropharyngeal cancers were lower, however, among blacks and Hispanics versus whites and non-Hispanics, respectively. Rates of anal cancer were lower among black women and Hispanics, but higher among black men, compared with their counterparts.

HPV-associated cancer rates also differed based on geographic location: Utah had the lowest rate (7.5 per 100,000 persons) while Kentucky had the highest rate (14.7 per 100,000). The study’s authors noted that most states with rates higher than the overall US rate (11.7 per 100,000) were located in the South.

The researchers pointed out that most cervical cancers can be prevented by regularly screening women aged 21 to 65 for precancerous lesions, though there are no effective population-based screening tools for other HPV-associated cancers.

The authors also reviewed two challenges with the report itself. Though the CDC and SEER databases are reliable, the authors wrote, “no registry routinely collects or reports information on HPV DNA status in cancer tissue, so the HPV-attributable cancers are only estimates.” The authors also noted that race and ethnicity data came from medical records and may be inaccurate in a small number of cases.