Tailoring breast cancer screening to a woman’s individual cancer risk might work better than annual mammograms, a new study says.

Women had breast cancers caught at an earlier, more treatable stage when assigned to risk-based screening, compared to those who got annual mammograms regardless of personal risk, researchers reported Dec. 12 in the Journal of the American Medical Association.

“These findings should transform clinical guidelines for breast cancer screening and alter clinical practice,” Dr. Laura Esserman, director of the University of California-San Francisco Breast Care Center, said in a news release.

For the study, researchers had more than 14,000 women receive breast cancer screening based on their risk, as determined by their age, genetics, lifestyle, health history and breast density:

• 26% were in the lowest risk category and were generally told not to screen until they reached age 50.

• 62% had average risk and were told to screen every two years.

• 8% had elevated risk and were told to screen annually.

• 2% had highest risk and were told to get two screenings a year, alternating between mammograms and MRI scans.

“The personalized approach begins with risk assessment, incorporating genetic, biological and lifestyle factors, which can then guide effective prevention strategies,” Esserman explained.

The research team compared how these women fared with another group of more than 14,000 who received annual mammograms.

All participants were recruited between September 2016 and February 2023, and followed through September 2025, the study said.

Results showed that fewer women were diagnosed with advanced cancers — stage IIB or higher — if they got risk-based screening.

Women with risk-based screening had about 30 cases of advanced cancer per 100,000 person-years, compared with 48 cases per 100,000 person-years for those getting standard mammogram screening. Person-years reflect the amount of time a person has spent in a study.

Risk-based screening can also reveal potential perils a woman might not know about, researchers said.

For example, 30% of women who tested positive for genetics that increase their breast cancer risk did not report a family history of breast cancer. Under current guidelines, these women would not normally be offered genetic testing.

“This is one of the first studies to offer genetic testing to all women, regardless of family history,” researcher Allison Fiscalini, director of the Athena Breast Health Network at UCSF, said in a news release.

“When used as part of a comprehensive risk assessment, these results could have a real impact on improving the safety and effectiveness of screening and prevention,” Fiscalini said.

Researchers are now actively enrolling participants for a follow-up clinical trial intended to better identify women at higher risk for more aggressive breast cancers.

Reacting to the findings, the American College of Radiology (ACR) said the study does not provide enough evidence to justify changing breast cancer screening guidelines.

Many of the women did not stick to the screening pattern recommended to them, the ACR noted, and the study did not turn up enough cancers to fuel the best statistical analysis.

“The number of cancers found is small – likely not representative of the population,” the ACR wrote in a statement on the study. “The number of patients in the highest risk group is less than 300.”