Breast cancer cases in U.S. women under 40 are climbing by nearly half a percent each year. Still, new research from Columbia University suggests the increase isn’t uniform across the country.
Understanding these regional differences could help identify high-risk groups and reveal ways to reduce cases. While past studies showed an annual 0.56% increase in invasive breast cancer across all age groups, the rate among women under 40 is more concerning. This rate is rising by over 3% per year.
REGIONAL PATTERNS REVEAL UNEVEN GROWTH
A study analyzing public health data from all 50 states between 2001 and 2020 found that breast cancer rates remained stable in some states. In others, the rates even declined. This discovery provides critical reference points for experts investigating the root causes of these disparities.
“Breast cancer incidence is increasing in U.S. women under 40. Until now, we didn’t know if these trends varied by region,” says lead author and epidemiologist Rebecca Kehm.
The study found the highest rates in Maryland, New York, New Jersey, Hawaii, and Connecticut. In contrast, the South was the only region where overall breast cancer rates did not rise.
WHO FACES THE HIGHEST RISK?
The study also highlights racial disparities in early-onset breast cancer. Non-Hispanic Black women had the highest overall incidence rates. Non-Hispanic white women were the only group to experience statistically significant increases across all regions.
The reasons behind these differences remain unclear. Researchers point to multiple factors, including exercise habits, hormonal contraceptive use, and genetic variations. Yet, genetics alone can’t fully explain the rising cases, as these changes occur over much longer periods.
“The increase in incidence is alarming and can’t be attributed solely to genetic factors,” says Kehm. “Nor can it be explained by changes in screening practices. Women under 40 are below the recommended age for routine mammograms.”
A GROWING CONCERN: CANCER IN YOUNG ADULTS
Breast cancer isn’t the only cancer on the rise in younger populations. Global cancer cases in people aged 14 to 49 jumped from 1.82 million in 1990 to 3.26 million in 2019. Death rates are also increasing.
To reverse this trend, researchers emphasize the need for targeted screenings, prevention efforts, and personalized treatment strategies.
THE PATH FORWARD: PERSONALIZED PREVENTION AND RESEARCH
Understanding which regions are experiencing higher rates of breast cancer can improve early detection and prevention.
“The causes behind rising early-onset breast cancer rates remain uncertain. However, studying how trends differ across populations can provide valuable insights. This can help shape future research,” says epidemiologist Mary Beth Terry.
This research underscores the need to tailor screenings and prevention efforts to specific demographics, ensuring young women at the highest risk receive timely interventions.
The study was published in Cancer Causes & Control.
