After Your Mammogram: Understanding Your Results
A mammogram is a series of X-rays of your breast tissue. It’s most often done to screen for breast cancer. Screening means looking for a problem before you have symptoms. A mammogram may also be used to learn more about a lump or other change in your breast tissue.
Your healthcare provider will explain your mammogram results. Ask questions if you don’t understand what you're told. Your provider may advise more tests to check anything that needs a second look. This is common. A call-back for another mammogram or other tests doesn't mean you have cancer.
The BI-RADS scoring system
Your mammogram results are scored from 0 to 6. This scoring system is known as the Breast Imaging Reporting and Data System (BI-RADS). The 6 categories make it easier to share results and make follow-up plans after your mammogram. Your healthcare provider will talk with you about your score.
Only a healthcare provider (radiologist) can interpret a mammogram. The technologist who does it can’t tell you the results. They can’t discuss what they see while doing the exam. A radiologist will look for problems in the images. They take this information and give it a score when they send the results to your healthcare provider.
Understanding your BI-RADS score
There are 6 categories for breast imaging results:
Category 0. This means your mammogram results are incomplete. The X-ray may have been cloudy. This can make it hard to read the images. Or, there may be a tissue change, but it's not clear. More information or imaging is needed to assign a score.
Category 1. This means your mammogram is negative. Negative means that no breast changes or signs of cancer were found. You should continue to have routine screenings.
Category 2. This means your mammogram has no signs of cancer. But other, noncancer (benign) changes were found. These may be cysts or benign calcifications. These changes are recorded. This is so they can be checked in future mammograms. You should continue to have routine screenings.
Category 3. This means your mammogram showed changes that are most likely not cancer (benign). But there is a slight (less than 2%) chance of cancer. You'll likely need a follow-up mammogram in 6 months. This is done to recheck the changed tissue.
Category 4. This means changes are seen on the images, but they're not clearly cancer. Your provider may advise you to have a biopsy. Category 4 has these subgroups:
4A. This means the chance of the change being cancer is low (between 2% and 10%).
4B. This means there's a moderate chance of cancer (between 10% and 50%).
4C. This means the chance of cancer is high (between 50% and 95%), but not as high as category 5.
Category 5. The changes seen are likely cancer (higher than 95% chance). A biopsy is strongly advised for a correct diagnosis.
Category 6. This means you’ve already been diagnosed with breast cancer and the pathologist has confirmed the diagnosis. Mammograms might be used to see how well treatment is working by looking at changes in the breast tissue over time.
Your breast density score
Your mammogram report will include information about how dense your breasts are. This means how much fibrous and glandular tissue is in your breasts in addition to fatty tissue. The more dense your breasts are, the harder it can be to see abnormal areas on mammograms. Having dense breasts is very common. There are 4 levels of breast density:
Category A. This means the breasts are not dense. They are almost all fatty tissue.
Category B. This means the breasts have scattered areas of dense glandular and fibrous tissue in the fat tissue.
Category C. This means the breasts are mostly dense glandular and fibrous tissue. This makes it hard to see small tumors. This may be called heterogeneously dense breasts on the report. This is common and not a cause for concern.
Category D. This means the breasts are very dense. This makes it hard to see tumors in the tissue.
If you have dense breast tissue, talk with your healthcare provider about what this means for you. Make sure they know your health history. Tell them if you know of anything in your history that raises your risk for breast cancer.
If your mammogram results are abnormal
Breast changes are common and usually not cancer. But the only way to be sure is to have more tests. Your healthcare provider may advise tests that can give clearer, more detailed images of the breast. You may have any of these:
If any of these tests show a solid mass or lump, you may have a biopsy. A biopsy is a procedure to take a small amount of tissue from an area. The tissue is checked for cancer cells.