What is BI-RADS? How to Interpret Mammogram Results

Mammogram screening is a crucial method for detecting breast abnormalities at an early stage. To standardize reporting and guide appropriate follow-up care, radiologists use the BI-RADS system (Breast Imaging Reporting and Data System), which classifies breast findings into 7 categories, from 0 to 6.

Each BI-RADS level represents a different level of suspicion for breast cancer and includes a recommendation for follow-up or treatment.

What Do BI-RADS Categories Mean?

BI-RADS 0 – Incomplete Further imaging (such as ultrasound or repeat mammogram) is required to make a complete assessment.

BI-RADS 1 – Negative No abnormalities detected. Annual screening is recommended.

BI-RADS 2 – Benign Findings such as cysts, fibroadenomas, or benign calcifications. No cancer. Continue routine annual screening.

BI-RADS 3 – Probably Benign Low risk of cancer (0–2%). Follow-up imaging is recommended every 6 months for up to 2 years.

BI-RADS 4 – Suspicious Abnormality Risk of malignancy (2–95%). A biopsy is recommended to determine if the finding is cancerous.

BI-RADS 5 – Highly Suggestive of Malignancy High likelihood of cancer (>95%). A biopsy should be performed immediately to confirm diagnosis and plan treatment.

BI-RADS 6 – Known Malignancy Cancer has been confirmed by prior biopsy. Imaging is used to monitor tumor size or response to treatment.