• Posted December 2, 2025

Up to 1 in 4 Breast Cancers Occur in Women Under 50, Study Shows

As many as 1 in 4 breast cancers occur in women younger than 50, a new study has found.

Among seven outpatient clinics in the New York region, 20% to 24% of breast cancers were found in women 18 to 49, according to results presented Monday at the Radiological Society of North America’s annual meeting in Chicago.

“This research shows that a significant proportion of cancers are diagnosed in women under 40, a group for whom there are no screening guidelines at this time,” researcher Dr. Stamatia Destounis, a radiologist with Elizabeth Wende Breast Care (EWBC)  in Rochester, New York, said in a news release.

The U.S. Preventive Services Task Force recommends mammography every other year starting at 40 and continuing through age 74, researchers noted.

The American Cancer Society recommends annual mammograms starting at age 45, but added that women can choose to begin breast cancer screening as young as 40.

For the new study, researchers tracked breast cancer diagnoses at EWBC between 2014 and 2024. EWBC has seven outpatient facilities located in a 200-mile radius of western New York.

The team identified nearly 1,800 breast cancers diagnosed in about 1,300 women under 50 over the 11-year period. Of those cancers, 81% were invasive, researchers said.

“Most of these cancers were invasive, meaning they could spread beyond the breast, and many were aggressive types — especially in women under 40,” Destounis said. “Some were triple-negative, a form of breast cancer that is harder to treat because it doesn’t respond to common hormone-based therapies.”

Women younger than 50 consistently accounted for 1 in every 4 breast cancers detected, even in years when fewer women in that age group got screened, results show.

“This is striking because it shows that younger women not only carry a stable and substantial share of the breast cancer burden, but their tumors are often biologically aggressive,” Destounis said. “That combination — steady incidence plus disproportionately aggressive biology — directly challenges age-based screening cutoffs and strengthens the case for earlier, risk-tailored screening approaches.”

Younger patients need to be taught how to check themselves for breast changes related to cancer, and should start screening earlier if they have other risk factors for cancer, Destounis said.

“This data reinforces that women under 50, especially those under 40, shouldn’t be seen as low risk by default and can absolutely benefit from risk assessment being performed as early as possible,” Destounis said.

“Those with a strong family history or genetic mutation, as well as certain minorities and ethnic backgrounds, are at higher risk for breast cancer at a younger age,” Destounis continued.

“We can’t rely only on age alone to decide who should be screened,” Destounis said. “Paying closer attention to personal and family history, and possibly screening earlier for some women, could help detect these cancers sooner.”

Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

More information

The U.S. Centers for Disease Control and Prevention has more on breast cancer screening.

SOURCE: Radiological Society of North America, news release, Dec. 1, 2025