HPV-Linked Cancers Among American Indian and Alaska Native People, 2013–2017

Human papillomavirus (HPV) causes nearly all cervical cancers and some cancers of the vagina, vulva, penis, anus and oropharynx (the back of the throat). Screening can catch cervical precancers, and the 9-valent HPV vaccine (9vHPV) can prevent about 92% of cancers attributable to HPV.

Earlier studies found lower rates of these cancers among American Indian and Alaska Native (AI/AN) people than in other groups — but those rates were probably too low, because AI/AN people are often misclassified by race in cancer registries. Rates also vary widely by region, so national totals can hide local problems.

How CDC counted

CDC used cancer registry data linked with the Indian Health Service (IHS) patient registration database — a method shown to improve accuracy for AI/AN populations. The analysis covered 2013–2017 and was limited to:

• counties in IHS purchased/referred care delivery areas (PRCDAs), which contain or border federally recognized tribal lands and have more AI/AN residents; about 53.3% of the AI/AN population lives in them;
• non-Hispanic AI/AN people, because population estimates overcount Hispanic AI/AN people.

Registries don't record HPV status, so the number of cancers caused by HPV was estimated from genotyping studies.

The six regions and the IHS purchased/referred care delivery area counties used in the analysis. Credit: Centers for Disease Control and Prevention.

What they found

An estimated 1,030 HPV-associated cancers were diagnosed among AI/AN people in 2013–2017. Of these, 740 (72%) were caused by HPV types that 9vHPV targets — 500 in women (330 of them cervical cancers) and 240 in men.

Compared with non-Hispanic White people in the same counties:

Rates are cases per 100,000 people, age-adjusted.

• Among women, cervical cancer made up 63% of HPV-associated cancers, compared with 39% among White women.
• Among men, oropharyngeal cancer was the most common HPV-associated cancer in every region — 82% overall, from 67% in Alaska to 86% in the Northern Plains.

By region

Among men, oropharyngeal cancer rates ranged from 3.3 per 100,000 in the Southwest to 12.2 in the Southern Plains.

Prevention: vaccination and screening

Vaccination. The Advisory Committee on Immunization Practices recommends routine HPV vaccination at 11–12 years and catch-up vaccination for everyone through age 26. Healthy People 2020 aimed for 80% of teens aged 13–15 to receive 2 or 3 doses.

HPV vaccination still lags other vaccines given at the same ages, suggesting local, culturally tailored efforts could help.

Screening. Cervical cancer is the only HPV-associated cancer with routine screening. In 2017, only 54.8% of AI/AN women were up to date, against a Healthy People 2020 target of 95%. CDC's National Breast and Cervical Cancer Early Detection Program offers screening to underserved women, and partnerships with tribal programs, states and others support outreach. The authors note that the COVID-19 pandemic may be disrupting screening and prevention in underserved communities.

Limitations

• HPV-caused cancers are estimates, since registries don't record HPV status.
• Only members of federally recognized tribes and people who used IHS services are included.
• Excluding Hispanic AI/AN people lowered overall incidence by less than 5% but may skew some states and regions.

Sources

Based on Melkonian SC, Henley SJ, Senkomago V, Thomas CC, Jim MA, Apostolou A, Saraiya M, "Cancers Associated with Human Papillomavirus in American Indian and Alaska Native Populations — United States, 2013–2017," Morbidity and Mortality Weekly Report 69(37), Centers for Disease Control and Prevention; a work of the United States government in the public domain. Original report.