January 25, 2010 Seminar: Health Disparities Interest Group

Geographic Distribution of Cervical Cancer Screening, Incidence, Stage and Mortality in the U.S.

Introduction

• Antoinette Percy-Laurry, co-chair of this year's HDIG Seminar Series, led introductions of all meeting attendees and introduced this month's speaker, Dr. Sean Altekruse.
  • Presenter: Sean Altekruse, DVM, MPH, Ph.D., Epidemiologist in DCCPS' Surveillance Research Program (SRP)
  • Presentation Title: Geographic Distribution of Cervical Cancer Screening, Incidence, Stage, and Mortality in the United States

Background

• Since the introduction of pap smears in the 1950s, cervical cancer rates have decreased by half, and are continuing to decrease after the recent introduction of Human Papillomavirus (HPV) vaccines.
  • 95% of cervical cancer cases are caused by 15 HPV types. Of these, HPV types 16 and 18 cause about 70% of cervical cancer cases.
  • Two vaccines, developed by Merck and GlaxoSmithKline, have been approved by the FDA, but challenges remain:
    • Cost barriers: ~$120 for each of three doses
    • Vaccines prevent new HPV cases but do not treat existing ones
    • 30% of cervical cancers have causes other than HPV types 16 and 18
  • For these reasons, the World Health Organization (WHO) advises using HPV vaccination as one part of an overall strategy to reduce the burden of cervical cancer
• As of 2009, there were an estimated 11,000 cervical cancer diagnoses and 4,000 deaths annually
• Some disparities in incidence and mortality are evident:
  • Hispanics and non-Hispanic Blacks have higher rates than non-Hispanic Whites and Asian/Pacific Islanders
  • Low socioeconomic status (SES) populations have higher rates
  • Certain geographical areas have higher rates

Methods

• County-level data were collected from a variety of sources
  • Incidence data, 1995-2004, from 35 states and DC: data from Surveillance, Epidemiology and End Results (SEER), and North American Association of Central Cancer Registries (NAACCR)
  • Death rates: National Center for Health Statistics (NCHS)
  • Screening: National Health Interview Survey (NHIS), Behavioral Risk Factor Surveillance System (BRFSS)
  • Stage at diagnosis: state-level data from SEER registries
  • Five race/ethnicity groups: Hispanic, non-Hispanic White, non-Hispanic Black, Asian/Pacific Islander, and American Indian/Alaska Native
• Spatial and temporal models were used to fill in missing data and software was used to account for low sample sizes in certain counties
• Maps were used to spatially visualize the results

Results

• High incidence was found in five geographic areas: Appalachia, Southeastern United States, lower Mississippi Valley, Texas/Mexico border, and Oklahoma/Texas panhandles
• Mortality followed a similar pattern, with additional localized increases
• Considering the central counties of the five largest urban areas (Los Angeles, New York City, Philadelphia, Houston, and Chicago):
  • These areas had a higher than average mortality rate
  • Racial/ethnic disparities varied by county
• There were higher rates among minorities and low SES groups
• Areas with low SES had high mortality rates from cervical cancer, as well as from cardiovascular disease and during infancy
• Limitations: smoothing of some small samples, potential bias of predictions from differences in the covariates

Conclusions

• Overall, areas with high incidence and mortality also tended to have limited uptake of screening practices and later stages of diagnosis
• Keeping these and previous findings in mind, 2008 data show that HPV vaccination is reaching the correct groups in terms of:
  • Race/ethnicity: 44% of Hispanic women, 36% of Black women, and 35% of White women have received the first dose of the vaccine
  • SES: 46% of those below the poverty level and 36% of those at or above it have received the first dose
  • Geography: Vaccination rates are highest in the Northeast. However, geographic disparities still remain in other areas.
• This data provides a good baseline of the period just before HPV-based prevention technologies, and can be used to allocate resources and monitor progress
• Future efforts need to balance the goals of reducing cervical cancer incidence and mortality with reducing the costs and adverse effects of screening

Discussion

• Availability of data on the 30% of cervical cancers not resulting from HPV types 16 and 18
• Concerns with the age range of screening data compared to the age range of cervical cancer incidence and mortality
• Importance of access to treatment after a person screens positive

Announcements

• Feb. 12: deadline for public comment on Office of Minority Health's (OMH's) National Plan for Action
• March 3-5: Cherokee Nation Cancer Summit – 3rd Bi-Annual Cancer Summit in Tulsa, OK
• March 5: "Hunger and Health: Focus on Childhood Hunger" presentation in Lipsett Auditorium, Main Campus with videocast at http://videocast.nih.gov at 8:30 a.m.
• No HDIG meeting in February; next meeting is scheduled for March 29.

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