What Does My Mammogram Result Mean

Screening for breast cancer is performed with a mammogram. A mammogram is an x-ray of the breasts that can detect either harmless cysts or calcium build up that may be concerning for cancer. A mammogram result is expressed as a BIRADS score. Based on the BIRADS score, some breast masses need a biopsy and others don’t. Let’s find out what this BIRADS score means.

BIRADS stands for “Breast Imaging Reporting and Data System” and was developed by the American College of Radiology to create a standardized and easy to follow method for reporting all mammogram results. There are 7 BIRADS categories. The first category is BIRADS 0, which represents an incomplete test. A mammogram may be noted as incomplete due to technical factors or poor positioning of a woman. In this case, you may require a more extensive mammogram with additional views and an ultrasound.

There are some BIRADS scores that are considered normal. In particular, BIRADS scores of 1 to 3 are considered harmless, but require different timeframes for follow up. A BIRADS score of 1 represents a completely normal mammogram without masses or other abnormality. In this situation, a woman can follow up with a repeat mammogram in 2 years. A woman with a BIRADS score of 2 may have a harmless mass, such as a cyst, on her mammogram. On your mammogram this mass will be noted as “benign,” which is not cancer and follow up can be performed in 1 – 2 years. Other the other hand, a BIRADS score of 3 means that a mass is found on mammogram which probably harmless and the probability of cancer is less than 2%. Mammograms with a BIRADS score of 3 require a shorter follow up period of 6 months with a more extensive mammogram and ultrasound. Unless something is found on follow up imaging, mammograms with a BIRADS scores of 1 to 3 will not require a biopsy.

Finally, there are some BIRADS scores that are concerning for cancer. BIRADS score of 4 to 6 are considered suspicious for cancer. A BIRADS score of 4 may have clusters of calcium formation which many suggest cancer. Albeit, the chances of cancer in this group is broad and ranges from 2 to 94%. Therefore, a woman with a mammogram that has a BIRADS score of 4 will require a biopsy. A mammogram with a BIRADS score of 5 is very suggestive on cancer. There is a 95-100% chance that an abnormality seen on mammogram is cancer in this group. A woman with a mammogram that has a BIRADS score of 5 will also need a biopsy. A BIRADS score of 6 only relates to woman that has known breast cancer and is undergoing a mammogram to evaluated another breast or response to chemotherapy. (1)

When you speak with your doctor about your mammogram results, it important to know your BIRADS score. This will help empower you to make you own informed decisions about the risk of cancer and when to get a biopsy. Importantly, there is a 10 – 30% chance that a negative mammogram may miss breast cancer. This is called a false negative result. A false negative result is more common in women with dense, or firmer, breasts. Using an ultrasound can decrease this false negative rate to 0 – 3%. (2) Therefore, if you remain concerned about your risk of breast cancer despite a negative mammogram, ask your doctor if a breast ultrasound is right for you.

REFERENCES
1. Mercado CL. BI-RADS update. Radiol Clin North Am. 2014 May;52(3):481-7. doi: 10.1016/j.rcl.2014.02.008. PMID: 24792650.
2. Moy L, Slanetz PJ, Moore R, Satija S, Yeh ED, McCarthy KA, Hall D, Staffa M, Rafferty EA, Halpern E, Kopans DB. Specificity of mammography and US in the evaluation of a palpable abnormality: retrospective review. Radiology. 2002 Oct;225(1):176-81. doi: 10.1148/radiol.2251010999. PMID: 12355002.