A large new study is challenging the long standing belief that all women need annual mammograms to protect against breast cancer. Researchers say that for many women, especially those at lower risk, less frequent screening may be just as safe while reducing unnecessary tests and stress. The findings are already sparking debate among doctors and public health experts about whether breast cancer screening should become more personalized.
The research was published in the Journal of the American Medical Association and comes from the WISDOM randomized clinical trial. WISDOM stands for Women Informed to Screen Depending on Measures of Risk.
The trial was launched in 2016 by Dr. Laura Esserman, a breast cancer surgeon and director of the Breast Care Center at the University of California, San Francisco. More than 28,000 women between the ages of 40 and 74 took part. None of the women had breast cancer when the study began.
Researchers wanted to know whether tailoring screening schedules to a woman’s individual risk could work just as well as the traditional one size fits all approach of annual mammograms.
Participants were randomly divided into two groups. One group followed standard annual mammography. The other followed a risk based screening plan.
To determine risk, researchers looked at genetics, including sequencing nine breast cancer related genes, along with other health and personal factors.
Women at the highest risk were advised to alternate between mammograms and MRI scans every six months. Those with elevated risk were told to have annual mammograms and counseling. Women at average risk were guided to have mammograms every two years. Women considered low risk were advised to delay screening until their risk increased or they reached age 50.
The women were followed for about five years to see whether cancers were detected later or at more advanced stages.
What the Results Showed
The study found that risk based screening did not lead to more advanced cancer diagnoses compared with annual mammograms. Advanced cancers were defined as stage 2B or higher. This suggests that personalized screening schedules were just as safe as yearly exams in catching dangerous cancers.
The approach also shifted testing toward the women who needed it most. Higher risk women had more imaging, more biopsies, and more cancers detected. Lower risk women had fewer procedures.
Researchers did not see the overall reduction in biopsies they had hoped for, but they said the findings still show that screening intensity can safely match individual risk.
In the study summary, the authors wrote that the results suggest risk based breast cancer screening is a safe alternative to annual screening for women ages 40 to 74 and could reduce unnecessary imaging.
When Annual Mammograms May Not Be Necessary
Based on the study, women at low or average risk may not need yearly mammograms. For these women, screening every two years or delaying screening until later did not result in more dangerous cancers being found.
Supporters of the approach argue that annual screening for everyone often leads to over testing in women who are unlikely to develop the disease, while women at higher risk may not get enough attention. They also point to the costs, estimated at about $13 billion a year, and say those resources could be used more effectively.
Dr. Laura Esserman said that screening has fallen short in many ways and that with such a large investment, the system should be improved to better serve patients.
Not everyone is convinced. Dr. Nicole Saphier, a radiologist and associate professor at Memorial Sloan Kettering Cancer Center in New Jersey, cautioned that the study may overlook what screening is designed to do.
She said that if early stage cancers like stage 0, stage 1, and stage 2A are not closely measured, it is hard to know whether personalized screening delays diagnosis in ways that affect survival or treatment intensity.
Dr. Saphier noted that more than 60 percent of breast cancers in the United States are diagnosed at stage 1 or 2A, where cure rates exceed 90 percent. She also warned that labeling women under 50 as low risk may be outdated, since breast cancer diagnoses are rising among younger women.
While acknowledging that mammography carries risks such as radiation exposure, false positives, anxiety, and possible over diagnosis, she said it remains the most effective evidence based tool for detecting breast cancer early.
When Annual Mammograms Are Still Recommended
According to critics of the new approach, annual mammograms should continue for average risk women starting at age 40 until long term data shows that alternative schedules improve survival.
Dr. Saphier emphasized that women should have their breast cancer risk assessed by age 25 to determine whether earlier or more frequent screening is needed. Until long term mortality data supports a shift, she said yearly screening remains the safest option for many women.
The WISDOM trial is the first randomized clinical study to test risk based breast cancer screening, and its findings are likely to influence future guidelines. Still, researchers acknowledge limitations, including the fact that not all women followed the recommended screening schedules.
Supporters see personalized screening as a smarter, more efficient approach. Skeptics worry that missed risks or uneven assessments could allow cancers to slip through the cracks.
For now, the study highlights a growing shift in medicine toward individualized care, while reminding women that screening decisions should be made with their doctors based on personal risk, family history, and comfort level.
HNZ Editor: Breast cancer is ugly and dangerous. Before you give up the annual exams, talk to your doctor – and you may want to wait until consensus is a bit more firm.
