What Does an Abnormal Mammogram Mean?

Mammograms are a common screening tool for breast cancer. They are a type of X-ray of the breast that evaluates the tissue for abnormal areas that could be cancerous. For many people, getting a mammogram can be anxiety-provoking — and waiting for a call back about the results of an abnormal mammogram can be scary. But abnormal mammograms are common, and most of the time they turn out to be nothing to worry about. 

Read on to learn what an abnormal mammogram might mean for you and what may happen next.

Why are mammograms important?

Mammograms help screen for breast cancer. They don’t prevent breast cancer, but they will help detect breast cancer earlier and make treatment more successful. Recommendations on when to start getting mammograms vary and will depend on your age, risk factors, and your own preferences. 

Does an abnormal mammogram mean that I have cancer?

No. While cancer may be the first thing that you think of, most of the time an abnormal mammogram does not mean you have cancer. There are many reasons for an abnormal mammogram, which means some additional follow-up testing may be necessary.

How common are abnormal mammogram results?

Abnormal mammograms are common. In fact, about 10% of mammograms are abnormal and require further testing, but less than 10% of those turn out to actually be breast cancer. 

What other conditions can cause abnormal readings on a mammogram?

There are many causes besides breast cancer that can lead to an abnormal mammogram, including:

• Dense breast tissue

• Calcifications

• Fluid-filled cysts 

• Benign tumors such as fibroadenomas

• Scarring

Often, there is simply an unclear image of the breast, so it needs to be repeated.

The COVID-19 vaccine can lead to temporary swelling of lymph nodes in the armpit, so if you are due for a routine mammogram and were recently vaccinated, you may want to talk with your healthcare provider about delaying the mammogram for 4 to 6 weeks. 

How do I interpret my mammogram result?

A radiologist will review and report your mammogram result. Your report will have a Breast Imaging Reporting and Data System, or BI-RADS, score. This will be a score from 0 to 6. Specifically:

• BI-RADS 0 means additional imaging is needed.

• BI-RADS 1 means a negative mammogram with noncancerous findings.

• BI-RADS 2 means there were noncancerous findings.

• BI-RADS 3 means there were likely benign findings, but a closer follow-up is needed.

• BI-RADS 4 means there was a suspicious finding that requires a biopsy.

• BI-RADS 5 means there was a highly suspicious finding for cancer.

• BI-RADS 6 is used when there is already a known cancer.

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In addition, your mammogram will describe the density of your breasts. This may affect the recommended frequency of your mammograms.

Does dense breast tissue complicate mammogram readings?

Yes. Dense breast tissue can make the interpretation of mammograms more difficult. Breasts are made up of glands, fat, and fibrous tissue, and your breast’s density will be described on your mammogram. Dense breast tissue shows up white on a mammogram, but so do abnormalities, so dense tissue can make abnormalities harder to evaluate. There is nothing abnormal about having dense breast tissue, but it can mean that you’ll need additional screening to stay safe.

Can hormones affect mammogram results?

Yes. Taking hormones such as birth control pills or hormone replacement therapy (HRT) can affect breast tissue and increase breast density.

What’s the next step after an abnormal mammogram?

After an abnormal mammogram, you may need further evaluation, such as:

• A diagnostic mammogram to take additional views of the worrisome breast area

• A breast ultrasound to take a closer look at the abnormal area

• A breast MRI to get a detailed look at breast tissue

• A biopsy of the concerning area to identify if it is benign or cancerous

Be sure to discuss these next steps and any questions about your results with your healthcare provider.

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Written by:

Christina Palmer, MD

Christina Palmer, MD, is a board-certified family physician with a focus on chronic care management, women’s health, and mental health. She’s the co-author of “Open Heart: When Open-Heart Surgery Becomes Your Best Option.”.

Edited by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. A pulmonologist and hospitalist, she practiced and taught clinical medicine at hospitals in London for a decade before entering a career in health education and technology.

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