Cervical cancer is one of the most preventable types of cancer affecting women in the United States. That's because there are two good screening tests for cervical cancer. One is the Pap test performed during a pelvic exam that can identify pre-cancerous cells and early-stage cancers, which are highly treatable. The second is testing directly for the presence of the cancer-causing human papillomavirus, or HPV.
Since virtually all cervical cancers are caused by HPV, much of the attention in recent years has focused on preventing infections in younger women through vaccinations against HPV.
But this may be taking attention off of another population that stands to benefit greatly from regular screening: women over 45.
Despite the fact that half of cervical cancers are diagnosed after age 49, participation in preventive screening steadily declines between ages 45 and 65, according to a first-of-its-kind analysis of three large national surveys led by the University of Michigan Rogel Cancer Center.
"Early detection is key to preventing invasive, devastating and potentially fatal cases of cervical cancer," says senior study author Diane Harper, M.D., M.P.H., a professor in the departments of Family Medicine and Obstetrics & Gynecology at the U-M Medical School. "From a public health standpoint, screening of women under 30 is considered to be the least effective investment of resources, because cancer tends to develop in middle age. Meanwhile, if a woman is screened after age 42, there is an 8 in 10 likelihood no cancer will be detected at her next screening a few years later -- meaning they're a vital way of catching problems early."
Harper adds, "The three federal datasets we looked at showed very similar results, although they were designed for different purposes and varying demographic populations. Our study was the first to examine trends across and between them."
The team's analysis, which appears in the journal Preventive Medicine, included the Centers for Disease Control's Behavioral Risk Factor Surveillance System (77,143 participants), the National Cancer Institute's Health Information National Trends Survey (1,580 participants) and the Health Resources and Services Administration's Bureau of Primary Health Care's Health Center Patient Survey (761 participants).
Broadly, the results show the nation is hovering around a 70% screening rate for cervical cancer, which is the minimum rate needed to lower the national incidence of the disease, Harper notes, but a more nuanced investigation shows several vulnerable subpopulations of women whose screening rates fall below that threshold.
Along with older women, lower screening rates were also found among women with lower levels of educational attainment and those who live in rural areas.
"Those without insurance also get fewer screenings," says Harper, who is a member of the U-M Institute for Healthcare Policy & Innovation. "Additionally, our analysis updates and confirms that screening rates did not increase after the Affordable Care Act required all health plans to cover cervical cancer screening with no-copays when performed by an in-network provider.
"To us, this suggests we still need to do a much better job at helping women, especially in these more vulnerable populations, understand the importance of screening as they age, and to continue to work to remove ongoing barriers to access."
One likely contributor to lower rates of timely screening is confusion about recommended screening intervals, as guidelines have shifted several times over the past two decades, says Harper, who also serves as senior associate director of the Michigan Institute for Clinical and Health Research.
"Internet searches may not yield the best screening recommendations, even when searching credible government websites," says Harper. "And new guidelines are scheduled to be released early next year. The best, most current evidence published by the U.S. Preventive Services Taskforce in the Journal of the American Medical Association finds primary HPV testing offers slightly better benefits for the general population, followed closely by Pap testing. Testing for both at the same time was associated with women undergoing a greater number of tests with little benefit."
Current cervical cancer screening guidelines recommend that:
- * Women 21-29 get screened with a Pap test every 3 years.
* Women 30-65, after talking to their doctor, should get:
- - An HPV test every five years or
- A Pap test every three years
* Women over 66 should ask their doctors whether they need continued screening.
The research was supported by the Michigan Institute for Clinical and Health Research (UL1TR002240) and the Rogel Cancer Center (P30CA046592)
Additional authors on the paper include: Melissa Plegue, Kathyrn M. Harmes, Masahito Jimbo and Sherri Sheinfeld Gorin, all of U-M.
Paper cited: "Three large scale surveys highlight the complexity of cervical cancer under-screening among women 45-65?years of age in the United States," Preventive Medicine. DOI: 10.1016/j.ypmed.2019.105880.