A U.S. nationwide study has shown that the proportion of women who have never been screened for cervical cancer increased by more than five percent per year between 2005 to 2023, by which time nearly one in three women aged 21 to 29 years and one in seven aged 30 to 65 years had missed out on screening.

Kalyani Sonawane, PhD, assistant director for data science and analytics at MUSC Hollings Cancer Center and co-investigators, say the study has identified “a troubling increase in never-screened women and overlap between populations at greatest risk and those least likely to receive preventive screening.”

Although cervical cancer is now preventable through the human papillomavirus vaccine, it continues to cause avoidable morbidity and mortality among women who have not been screened.

“While prior studies have focused on women who are not up-to-date with screening recommendations, very little was known about the proportion of women who have never been screened at all,” Sonawane told Inside Precision Medicine. “We wanted to better understand this population because women who have never been screened are missing a critical opportunity to prevent cervical cancer.”

To do so, they reviewed data from the National Health Interview Survey (NHIS), which took place every two to three years between 2005 and 2023, for more than 100,000 women eligible for cervical cancer screening. The women were predominantly White (56%) with some college education (29%), private health insurance (63%), and were typically living in urban areas (88%) in the Southern United States (37%). HPV vaccination rates among the 23,502 women aged 21 to 29 years ranged from 5.7% in 2008 to 54.0% in 2019.

The researchers report in JAMA Network Open that, among the 23,502 women aged 21 to 29 years, the proportion who had never been screened for cervical cancer increased from 12.5% in 2005 to 31.9% in 2023, which corresponded to an annual increase of 5.2%. The rate of increase was greater between 2010 and 2023, at 7.9%.

Sonawane and co-authors comment that “the near-doubling in the proportion of unscreened younger women is concerning,” because “early engagement with screening sets the trajectory for lifelong screening behavior.”

They add: “Findings from the current study, together with a 2019 NHIS analysis, indicate that among women aged 21 to 29 years, nearly eight million (45.5%) remain unvaccinated, and almost one-third of these women have also never been screened, highlighting substantial missed opportunities for both primary and secondary prevention.”

For the 82,760 women aged 30 to 65 years, who are at the highest risk for developing cervical cancer, the proportion that had never undergone screening increased from 5.3% in 2005 to 14.8% in 2023, at a rate of 6.8% per year.

Of note, regional- and distant-stage cervical cancer incidence each increased by more than two percent per year from 2017 onwards among these women, a finding the researchers describe as “troubling, particularly when viewed in the context of the proportion of women who have never been screened for cervical cancer over the last two decades.”

Sonawane said that “although the team expected to see some decline in screening participation, the magnitude and pace of the increase in women who have never been screened was surprising.”

She continued: “The findings suggest that barriers to cervical cancer prevention may be affecting a growing segment of the population and warrant urgent attention.”

The study didn’t investigate why women are choosing not to undergo screening, but Sonawane believes the reasons are likely multifactorial.

“Prior research points to barriers such as limited access to healthcare, lack of insurance coverage, lower awareness of screening recommendations, competing life priorities, and missed opportunities for provider recommendation,” she said. “Structural and socioeconomic factors also play an important role in determining whether women can access preventive services.”

Indeed, subgroup analyses showed that minoritized racial groups, uninsured women, and those residing in the Southern states, had a greater likelihood of never having cervical cancer screening.

For example, among women aged 21 to 29 years, never-screening was highest among Asian women, at 44.3%, compared with 28.8% among non-Hispanic White women, and among high school graduates (39.0%) or women a college or associate’s degree (35.0%) versus those with a master’s or doctoral degree (17.1%).

Sonawane concluded that the findings “underscore a growing gap in cervical cancer prevention among young women and during midlife.”

She added: “Understanding who remains unscreened can help guide more targeted outreach, risk assessment, and prevention strategies to reduce cervical cancer disparities.”