BI-RADS (or BIRADS)
The BIRADS categorisation is a scale that summarises the findings of radiological findings of breast examinations: mammography, breast ultrasound and mammography. It is used to accurately code the likelihood of the tests showing cancer in the breast. It is a very useful categorisation that allows communication between doctors involved in the care of patients with breast conditions. It was originally developed by the American College of Radiologists (ACR) for mammography, but is now also used in breast ultrasound and MRI. You will find the conclusion of your exam at the end of the accompanying radiology report.
BIRADS Category 0: Inadequate Examination
The examination performed is not sufficient to evaluate the findings. It may seem vague, but additional testing will be needed to express the possibility of a suspicious finding or not. A comparison with previous tests, specialised mammograms or breast ultrasound may be needed. When the screening is completed, another classification on the BIRADS scale will be given.
BIRADS category 1: Negative screening
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The test showed only normal findings. There is nothing much for the radiologist to comment on. The screening continues with the standard age-appropriate screening tests.
BIRADS category 2: Benign findings
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Here there are findings, but they clearly appear benign and do not require further investigation. This category includes findings that have been shown to be benign by a previous breast biopsy. Examples of BIRADS 2 findings are:
- Simple breast cysts
- Typical fibroadenomas, especially when discovered at an early age
- Tumoural apoptosis
BIRADS category 3: Possibly benign findings but requires reassessment
This category is where the uncertainties start. The findings are most likely (98%) to be benign, but unless a breast biopsy has been performed to be certain of the diagnosis (histological identification), a radiological re-examination is required no later than 6 months. If any biopsy is performed on a BIRADS 3 test finding and benignity is found, then from then on the test will no longer be considered BIRADS 2.
BIRADS 4: A highly suspicious finding requiring immediate breast biopsy
This category is further divided into 3 subcategories:
- BIRADS 4a.
Low suspicion of breast cancer but histological identification by biopsy of the area - BIRADS 4b
Intermediate suspicion of breast cancer but histological identification by biopsy of the area - BIRADS 4c
Moderate (50%) suspicion of breast cancer and histological identification by site biopsy
Following such a result on examination, the woman should immediately refer to her mastologist who is appropriately trained to perform histological identification by cut needle biopsy under ultrasound guidance. Further course will be commensurate with the histological examination and may mean:
- Negligible benignity that does not require surgery and the woman is followed up
- Nervous benignity requiring breast surgery and the woman will speak with her mastologist to schedule surgery as appropriate
- Malignment is detected in the breast, at which point further action is initiated by the woman and breast cancer surgeon for proper and prompt treatment
BIRADS Category 5: Highly suspicious finding – immediate biopsy and treatment
Unfortunately, findings in this category are usually (95% of the time) breast cancer. The woman should contact her breast specialist immediately. Treatment begins with preoperative diagnosis with guided biopsy of the problem area. After histologic identification of the cancer type, staging tests will be done and the final treatment plan will be decided.
BIRADS category 6: Known cancer from previous biopsy
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This category is used when the test finding is already histologically confirmed cancer. It may, for example, be seen in the breast MRI report done preoperatively, after the diagnosis of cancer, to rule out polyposis.
The ACR BI-RADS scale page wants to answer frequently asked questions such as:
- How do I know if my mammogram is good?
- What does my mammogram and breast ultrasound report say;
- Is my mammogram worrisome?
- When should I have a biopsy on a breast finding?
- What is the histological identification of a breast morphoma?