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  • Women who receive a false-positive mammography have a higher likelihood of developing breast cancer in the following 20 years, according to a new study.
  • Women who had the highest risk were between 60 and 75 years old and who had low breast density.
  • Experts recommend personal monitoring programs for women who get false-positive results, and staying up-to-date with screenings, mammograms and doctor visits.

A new study published this month in JAMA Oncology shows women who receive a false positive mammography result are more likely to develop breast cancer over the next 20 years.

Those who are at the highest risk of developing breast cancer are between 60 and 75 years old and have low breast density.

The risk was also elevated in four to six years after a false positive result.

Breast cancer is one of the most common cancers among women in the U.S. with approximately 297,790 new cases diagnosed in 2023, according to the American Cancer Society.

Researchers examined 45,213 women who received a false positive result and 452,130 women of the same age who did not. They also looked at the mammographic density of 12,243 women from the Karolinska Mammography Project for Risk Prediction of Breast Cancer study.

Xinhe Mao, study author and postdoctoral researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet in Sweden, said in a news release: “It’s important to accentuate a long-term awareness of breast cancer in women who get false positive mammography results. It might be beneficial to draw up personal monitoring programs for these women with careful follow-ups over the years immediately following.”

Dr. Claudia Cotes, a breast cancer radiologist with UTHealth Houston, said that some breast changes that lead to benign growths may end up increasing the risk of breast cancer.

“These benign biopsies can represent a very early stage of proliferation that may at the end, with time, have a higher chance to develop into a cancer,” Cotes said.

Another possibility is that false-positive results can lead to further imaging and evaluation as part of the patient’s follow-up, which may in turn increase the likelihood of detecting early breast abnormalities that would not have been found without the false-positive result, Cotes added.

“The most direct explanation is that the radiologist is picking up on a subtle change on the mammogram that is either because there is actually a very small breast cancer already or portends the development of a breast cancer, even though none is present yet,” said Dr. Ilana Richman, Internal Medicine, Yale New Haven Health and health services researcher, Yale School of Medicine. “It is also possible that a false positive is a more general marker of increased breast cancer risk. Several of these explanations may be present at once.”

In this study, the authors observed that women with a false positive were at the highest risk of developing breast cancer on the same side of the body as the false positive.

But women with a false positive also had a more modestly elevated risk of developing breast cancer on the opposite side of the body, which suggests the false positive result conveys something about breast cancer risk in general, and not just in the area identified on the mammogram, Richman noted.

As noted in the study, women in the 60–75 age bracket are at a higher risk for developing breast cancer compared to women in the 40–49 age bracket.

“Older women in the 60-75 age bracket may have a higher risk because breast cancer risk generally increases with age,” said Cotes. “Additionally, breast tissue undergoes changes with age, and the likelihood of developing breast cancer may be influenced by hormonal changes and other factors associated with aging.”

If a woman in her 40s has an abnormal mammogram, it is more likely to be a false positive than if a woman in her 60s or 70s has an abnormal mammogram, Richman explained. This may mean that a false positive mammogram for younger women is less meaningful since false positives are generally pretty common.

Women with low mammographic density are at a higher risk because the denser the breast tissue, the harder it becomes to identify abnormalities.

“Women with low mammographic breast density (categorized as BI-RADS A and B) may have a higher risk because dense breast tissue can make it more challenging to detect abnormalities on mammograms (the dense tissue may obscure small cancers),” Cotes stated. “Therefore, cancer is more easily detected in breasts with lower density.”

Cotes continued: “The diagnosis in patients who receive a false-positive result and have dense breasts having lower risk may indicate that abnormalities were possibly missed during the initial screening due to masking by breast density. As a result, the increased risk may be linked to delayed detection or missed breast cancer.”

Richman agreed dense breast tissue can hide small abnormalities and make it harder to spot early breast cancers.

“This may also mean that radiologists are less able to pick up on these subtle changes that are eventually deemed ‘false positives,’ but actually convey information about future risk of breast cancer, Richman added.

For women who get false-positive results, it would be beneficial to conduct careful follow-ups over the following years.

“This is especially important as we try to lean into personalized or individualized patient care,” said Cotes. “These results show that a history of previous biopsy with false negative results should be considered when assessing the patient’s overall risk of breast cancer in addition to other individual risk factors, such as age, breast density, family history, etc., which ultimately will be beneficial when developing a personalized monitoring program.”

This may include more frequent imaging and clinical follow-ups over the years immediately following the biopsy or additional imaging modalities such as ultrasound, MRI, or contrast-enhanced mammography. Since this study indicates that the risk of breast cancer remains elevated for up to 20 years after a false-positive result, long-term awareness and surveillance are important, Cotes added.

Self-monitoring and self-breast exams are important for the detection of breast cancer.

“We recommend patients to have a general breast awareness, which means that women must familiarize with how their breasts normally look and feel and be aware of any changes in size, shape, texture, or appearance,” Cotes stated.

Performing self-breast exams monthly, a few days after your menstrual period when your breasts are less likely to be tender or swollen is helpful to keep track of any changes, Cotes explained. If you’re postmenopausal, you may choose a specific date each month to perform the exam for consistency.

Here are steps to check your breasts:

  • Stand in front of a mirror with your arms at your sides and look for any changes in breast size, shape, or symmetry. You must also check for skin dimpling, skin or nipple changes, or nipple inversion.
  • Then, you may use the pads of your fingers to feel your breast in a circular motion, moving from the outside to the center, including the area from the edge of the clavicle to the inferior breast fold (where the breast ends by the belly) and the axilla. Pay attention to any lumps, knots, or changes in texture, such as areas of thickening. You can also repeat the process lying down.

“If you notice any changes or abnormalities while doing this self-evaluation, or other changes such as nipple discharge (especially if only from one breast and bloody) or a constant pain in the same region of the breast that does not improve, you must see your doctor,” said Cotes. “Keep in mind that while self-exams are important, they do not replace regular clinical breast exams by a healthcare provider and a yearly mammogram.”

A new study shows women who receive a false-positive mammography have a higher chance of developing breast cancer in the next 20 years.

Women who had the highest risk were between 60 and 75 years old and who had low breast density.

Breast cancer risk increases with age due to changes in breast tissue and hormones.

For women who get false-positive mammography results, experts recommend regular screenings, mammograms and doctor visits.