False-Positive Mammogram Result May Signal Higher Breast Cancer Risk
A false-positive mammogram result was linked to a higher risk of developing breast cancer over the following 20 years, according to a large Swedish study.
The research was published online on Nov. 2, 2023, by the journal JAMA Oncology. Read “Breast Cancer Incidence After a False-Positive Mammography Result.”
What is a false-positive mammogram result?
When a mammogram shows an abnormal area that looks like cancer but turns out to be normal, it’s called a false positive. In the United States, about 11% of women receive a false-positive mammogram result.
Ultimately the news is good: no breast cancer. But the suspicious area usually requires follow-up with more than one doctor, extra tests, and extra procedures, including a possible biopsy. There are psychological, physical, and economic costs that come with a false positive.
About the study
Earlier research has consistently shown that women with false-positive mammogram results have a higher risk of breast cancer in the next 10 years compared to women who don’t have a false-positive result. But little is known about breast cancer risk beyond 10 years, which is why the researchers did this study.
The study included 497,343 Swedish women ages 42 to 59 who had information in the Stockholm Mammography Screening Program, which was started in 1989, and invites all Stockholm County women aged 50 to 69 years to be screened every 2 years:
45,213 women received a first false-positive mammogram result between 1991 and 2017
452,130 women had never had a false-positive mammogram result
The women who had a false-positive mammogram and women who didn’t have a false-positive mammogram were matched based on:
their age
the year they had a mammogram
their screening history
The study also included a smaller set of women for whom the researchers had breast density information. Of those women:
1,113 women with a false-positive mammogram result
11,130 women matched on the same factors as above
Rates of breast cancer over 20 years of follow-up were:
11.3% among women with a false-positive mammogram result
7.3% among women who never had a false-positive result
So women who had a false-positive mammogram result had a 61% higher risk of developing breast cancer in the next 20 years than women without a false-positive result.
The risk of developing breast cancer was even higher among women ages 60 to 75 compared to women ages 40 to 49.
Surprisingly, women with lower breast density had a higher risk of developing breast cancer after a false-positive than women with dense breasts.
Women with a false-positive result also had a higher risk of dying from breast cancer or other causes than women without a false-positive mammogram result.
Why is risk higher after a false-positive result?
The researchers discussed some reasons that could explain why breast cancer risk is higher after a false-positive mammogram result.
One is that a very small breast cancer was missed on the previous mammogram. The previous mammogram also could have missed what’s called proliferative benign breast disease. Benign breast disease isn’t cancer, but certain types of benign breast disease can increase the risk of breast cancer. “Proliferative” means the cells are multiplying and growing rapidly. Atypical ductal hyperplasia and atypical lobular hyperplasia are two types of rapidly growing benign breast disease linked to a higher risk of breast cancer.
What this means for you
The paper concluded with three points that women and their doctors should consider.
In addition to ordering a biopsy of the suspicious area after a false-positive mammogram result, doctors should also consider a woman’s age and breast density when developing a woman’s personalized screening program.
Intensive screening, possibly using techniques other than mammography, such as ultrasound, for two years after a false-positive result may offer benefits.
Doctors should make sure women with a false-positive result are aware of their breast cancer risk and the likelihood that it’s now higher after the false-positive result. In most countries with breast cancer screening programs, screening mammograms stop at age 70. Women who have false-positive mammogram results may benefit from screening that continues after age 70.
If you’ve had a false-positive mammogram result, it makes sense to talk to your doctor about this study and your personal risk of breast cancer by doing a breast cancer risk assessment. Once you know your risk, you can develop a screening plan tailored to your unique situation.
If you had a false-positive mammogram result in your 60s or 70s and would like to be treated for breast cancer if it were diagnosed, talk to your doctor about continuing screening mammograms and ask how often you should have them.
— Last updated on February 8, 2024 at 10:24 PM