November 15, 2004
Dear Referring Provider,
Recently the American College of Radiology (ACR) revised the BI-RADS categories for mammography reporting. They have added subcategories to the Category 4/Suspicious and also added a Category 6/Known Biopsy Proven Malignancy to the reporting system. We would like to take this opportunity to describe the criteria for the new categories and review the criteria for the existing categories; please see the attached sheet for a detailed description of all the categories.
Thank you for this opportunity to review the ACR BI-RADS mammography reporting system. If you have any questions or concerns, please feel free to call me, or any of the Inland Imaging mammographers.
Florence Gin, MD
Director of Breast Imaging
BI-RADS Mammography Reporting
Category 0/Additional Evaluation: A category 0 report is an incomplete evaluation. Category 0 can be used for two scenarios:
1. The report will ask that the patient return for additional imaging, either special view mammography and/or breast ultrasound to further evaluate an area in question.
2. The report will state that review and comparison of prior mammograms are needed to complete the interpretation of the current exam.
Category 1/Negative Findings: A normal exam. The report will state the patient should return for normal interval follow up mammograms. This would be yearly for most women over 40. See the American Cancer Society (ACS) guidelines.
Category 2/Benign Findings: A normal exam with benign findings. The report will state the patient should return for normal interval follow up mammograms. This would be yearly for most women over 40. See ACS guidelines.
Category 3/Probably Benign Findings: An exam with findings which are almost certainly benign: less than a 2% chance of malignancy. Category 3 assessments usually result from additional evaluation after a screening mammogram with a category 0. Generally, category 3 assessments will have a short-term interval follow up recommendation, most commonly at 6 months.
Category 4/Suspicious: In the past Category 4 was a mammogram with a finding that was considered from 2-95 % suspicious for malignancy. The broad range of risk of malignancy is what prompted the subcategories. These findings all warrant needle biopsy, but expected pathology and recommended follow up may differ.
Category 4A/Low Suspicion: A finding in this category is felt to be sufficiently suspicious; enough to warrant intervention, but a malignant pathology is not necessarily expected.
Category 4B/Intermediate Suspicion: Findings in this category warrant close radiologic and pathologic correlation. Follow up with a benign result depends on radiologic/pathologic concordance.
Category 4C/Moderate Suspicion: Findings in this category are of moderate concern but not classic (as in Category 5) for malignancy. A malignant pathology result is expected.
Category 5/Highly Suspicious of Malignancy: This exam has findings which almost certainly represent breast carcinoma with a >95% probability.
Category 6/Known Breast Cancer: This category has been added for breast findings confirmed to be malignant by biopsy but prior to definitive therapies such as surgical excision, radiation therapy, chemotherapy or mastectomy. This category is appropriate for second opinions or for the monitoring of response to neoadjuvant chemotherapy.