A breast biopsy is ordered based on results from medical imaging of the breast, such as mammogram, breast ultrasound, and/or breast MRI. Breast biopsy is a procedure that removes small pieces of tissue from within the breast. A needle is guided into an area of concern to take a small tissue sample, which is sent to a laboratory for analysis.

This procedure may also be referred to as breast intervention and might be suggested after imaging shows an area that needs to be investigated further.

When reporting breast imaging results, radiologists use a standard system to describe medical imaging findings and results. Called BI-RADS® (Breast Imaging Reporting and Data System), this system sorts the results into categories based on the likelihood of cancer and where biopsy is appropriate.




Negative – nothing new or abnormal was found.


Benign – nothing cancerous found.  Benign calcifications, masses, or lymph nodes noted in the breast.


Probably benign – very low (~2%) chance of being cancer. Follow-up is usually recommended with repeat imaging in shorter intervals for at least two years.


Suspicious abnormality – biopsy recommended; likelihood of cancer sub-categorized as follows:

  • 4A – low (2- 10%)
  • 4B – moderate (10-50%)
  • 4C – high (50-95%)


Highly suggestive of malignancy – 95% or more chance of cancer; biopsy strongly recommended.


Known biopsy, proven malignancy – used for findings that have already been shown to be cancer by a previous biopsy.



Mammography – specialized X-ray technology that takes a series of images of the breasts and provides a detailed look at the internal structure of breast tissue. Sometimes after a screening mammogram, you may be asked to return for additional breast imaging to examine a specific area of concern, to assess a change in the breast tissue compared to previous images, or to investigate an abnormality.

Breast ultrasound – you may be sent for a breast ultrasound if it’s determined on a mammogram that you have high breast density. You could have either an automated or handheld breast ultrasound which use high frequency sound waves to see the internal structure of your breast. It can also be requested to examine a specific area of concern that has been identified on a mammogram. Breast ultrasound helps provide a more detailed look and ensures you receive a complete breast exam.

Breast magnetic resonance imaging (MRI) – MRI uses a strong magnetic field to provide very clear images of the body and can be ordered to investigate concerns in your breast tissue.


Dense breast tissue can only be determined by mammography and is not something that can be felt or seen. Dense breasts have less fat and more fibroglandular tissue, which can make it difficult to detect changes in the breast and small cancers may be hidden.

Dense breast tissue also increases the risk of breast cancer, especially in older women. For women with dense breast tissue in 75% or more of their breasts, their breast cancer risk is double relative to the general population. Using both mammography and ultrasound together can help provide a more complete picture of your dense breast tissue.


Prior to booking your biopsy, we will ask you about any history of bleeding or allergic reactions to local freezing. We recommend you arrange for a driver to take you home after your appointment.

Please wear a two-piece outfit (e.g., shirt and pants), so you can change for the exam more comfortably. You will be asked to remove your clothing from the waist up and given a robe. Once you are changed, we will escort you to the exam room where the technologist will go over the consent form, explain the procedure, and answer any questions you may have.

We will then perform a pre-scan to document the area of interest. Your breast area will need to be visible to your technologist for the exam. The radiologist will administer local freezing and guide a thin needle into the correct location under image guidance. Band-Aids will be placed over treatment areas.

You will then be checked by the technologist and if there are no concerns, you are free to leave with your driver.

SPECIAL NOTE: The procedure may vary depending on the biopsy method:

  • Fine Needle Aspiration Biopsy (FNA) – A type of ultrasound-guided biopsy in which a very thin needle and syringe are used to remove (aspirate) a small amount of fluid or cells from a lesion.
  • Ultrasound-Guided Core Biopsy – A special hollow needle is used to take a small cylinder-shaped (core) sample of tissue from a lump or abnormality.
  • Stereotactic (Mammography-Guided) Core Biopsy – A needle is inserted into the breast to obtain a tissue sample of the area of interest to be sent for pathologic assessment. This exam is done under mammographic guidance and uses local freezing.
  • Wire Localization – A fine wire marks the exact location of an abnormality, before a surgeon removes a lump. Once the abnormality is localized within the breast tissue, a local freezing is used to numb the area. A thin wire with a hook on the end is inserted, either by mammographic or ultrasound guidance. Once the wire is correctly placed you will be ready for surgery. Sometimes the radiologist will ask for additional images before you leave the clinic to ensure the wire is in the correct position.


According to the Canadian Cancer Society, one in eight Canadian women will be affected by a breast cancer diagnosis in their lifetime. However, when breast cancer is detected early, before it’s clinically apparent (e.g., palpable lump), it’s more likely to be small and more easily treated. Small cancers detected early can be removed and breast conserving surgery can be performed. Additionally, small cancers often do not require chemotherapy or radiation therapy.

The best way to detect breast cancer early is through regular screening mammograms. Your Alberta Health Care Insurance Plan covers yearly mammograms starting at age 40. Having regular mammograms allows a radiologist to compare your images from year to year, identifying changes that may be occurring in the breast over time. It’s also important to be aware of any changes in your breasts, such as new pain, lump, nipple discharge, or any heat or redness, and to report those to your doctor.

Mayfair Diagnostics has 12 locations which offer mammography exams, and, except for our Coventry Hills location, all of them use the Senographe Pristina mammography system – which helps provide a more comfortable mammogram. Visit our breast imaging page for more information.



Alberta Health Services (2023) “Breast Screening.” Accessed February 27, 2023.

American Cancer Society (2022) “Understanding Your Mammogram Report.” Accessed February 27, 2023.

American College of Radiology (2023) “Breast Imaging Reporting & Data System (BI-RADS®)” Accessed February 27, 2023.

Canadian Cancer Society (2022) “Breast cancer statistics.” Accessed February 27, 2023.

Coldman, A., et al (2014) “Pan-Canadian Study of Mammography Screening and Mortality from Breast Cancer.” Journal of the National Cancer Institute. November 2014, 106 (11).

Mayo Clinic Staff (2021) “Breast biopsy.” Accessed February 27, 2023.

Tabar, L., et al. (2019) “The incidence of fatal breast cancer measures the increased effectiveness of therapy in women participating in mammography screening.” Cancer. Accessed February 27, 2023.

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