Radiologists classify lumps, masses and densities that appear on your mammogram with a classification system called BI-RADS (Breast Imaging Reporting and Data System). BI-RADS is a quality assurance tool designed to standardize mammography reporting, reduce confusion in breast imaging interpretation and help monitor outcomes.

BI-RADS was established by the American College of Radiologists as a scheme for putting the findings on mammograms into a small number of well-defined categories. Although BI-RADS started out only for mammograms, it was later adopted for use with MRI and ultrasound as well. BI-RADS classification is not a formal requirement for most radiologists to use, but most do. Remember, only biopsies of suspicious breast tissue will give a definitive answer about cancer.

A negative diagnostic mammogram with a benign, or “probably benign”, finding is classified as BI-RADS 1, 2 or 3. BI-RADS category 1 is “negative” with “nothing to comment on”, i.e., no densities, lesions or masses. BI-RADS category 2 is a “benign finding” and BI-RADS category 3 is a “probably benign finding” that warrants a follow up imaging in six months to see if the lesion or mass increases in size.

If a mammogram is classified into BI-RADS category 3, it tends to have a very low positive predictive value (less than 2%), meaning a low change of cancer. BI-RADS 3 often causes a 6 month follow up mammogram, but the lesion is not expected to change over the interval period. If a BI-RADS 3 lesion shows any change during the follow up mammogram, it will change into a BI-RADS 4 or 5 and appropriate action should be taken. After the initial follow up mammogram at 6 months, a bilateral mammogram follow up examination should be done at 12 and 24 months after the initial mammogram.

A BI-RADS category 4 mammogram has a positive predictive value of about 30%. BI-RADS 4 is reserved for findings that do not have the classic appearance of malignancy, but have a wide range of probability of malignancy between 2% and 95%. In BI-RADS 4, the radiologist has a sufficient concern to urge a biopsy.

A BI-RADS category 5 mammogram is almost certainly predictive of breast cancer, with a positive predictive value of about 95%.

A BI-RADS category 6 is a “proven malignancy” that is confirmed by a biopsy.

Your physician will not discuss your BI-RADS category with you. It is much more likely that your doctor will explain that your mammogram was negative, you have a density in your breast that should be monitored, or you need a biopsy. However, nothing is stopping you from asking you doctor, “What is my BI-RADS category?” Your doctor will have your BI-RADS category on the mammogram report and with this article, you will know the significance of your particular category. Remember, you must ask your doctor for your BI-RADS category–otherwise, your doctor will never bring it up.

What you can do if you want more information about screening for breast cancer

If you want more information about screening for breast cancer, I welcome your phone call on my toll-free cell at 1-866-889-6882. You are always welcome to request a FREE copy of my book, The Seven Deadly Mistakes of Malpractice Victims, by sending an e-mail to me at jfisher@fishermalpracticelaw.com