When we think of an ultrasound, our minds go to the excitement of the first images of the baby in the mother’s rounded belly. But did you know that this same device can be used as part of breast cancer diagnosis? It’s known as a breast ultrasound.
What is a breast ultrasound?
Ultrasound uses sound waves to produce images of the inside of the breast. As with mammography, only a medical imaging technician can perform this test. You must get a prescription from your doctor for a breast ultrasound.
How does it work?
A probe projects high-frequency sound waves through the gel into the body in the area under examination. These waves are then instantly translated into images on a screen. This exam poses no risks. It does not use radiation and is not painful in the least.
When is a breast ultrasound indicated?
Your doctor may order a breast ultrasound before or after a mammogram.
Why before?
If a young person has a suspicious mass, her doctor might order an ultrasound as a first investigative test. Remember that breast cancer—although rare—is the most frequently diagnosed cancer during pregnancy.
Why after?
Ultrasound is a useful follow-up to a mammogram that revealed an abnormality at high risk of being cancerous. Ultrasound does not provide a definitive breast cancer diagnosis. All the diagnostic tests are important. However, ultrasound does provide complementary information for determining if the patient has breast cancer and the appropriate treatment plan. Ultrasound can also be used during the biopsy to guide the radiologist in manipulating the needle.
Ultrasound provides images that a mammogram cannot. For example, it can be used to define the nature of a mass. Tumours are generally solid masses, but mammograms cannot distinguish between fluid-filled or solid masses, while ultrasound can. When there is a solid lesion, the doctor will recommend a biopsy to define the characteristics of the mass. In all instances, ultrasound is used as a complementary test in the pre-diagnostic process. It offers more information on the nature of the abnormality detected to determine if more specific tests are required.
How to prepare for a breast ultrasound
You don’t need to prepare for an ultrasound. The only advice is to wear clothing that allows you to easily remove your top, because the exam is performed on a bare torso. You are also advised to refrain from applying cream before the exam, as this can affect the quality of the images.
How is a breast ultrasound performed?
A medical imaging technologist or radiologist will ask you to lie on a table and expose your breasts. A clear gel will be applied to the area to be examined, then a probe is guided over the skin to obtain images of the inside of the breast on a screen. Images of the area of concern are taken.
The whole process lasts only 10 to 20 minutes. When the exam is complete, you are free to resume your normal activities. There are no side effects or specific instructions associated with breast ultrasound.
What do the results mean?
As with mammograms, radiologists issue a report using the BI-RADS (Breast Imaging-Reporting and Data System) classification to classify the lesion.
- BI-RADS 0: Incomplete assessment, further imaging is needed
- BI-RADS 1: Normal mammogram
- BI-RADS 2: There are benign (i.e., not serious) abnormalities that do not require monitoring or further examination
- BI-RADS 3: There is an abnormality that is probably benign for which short-term monitoring (three or six months) is recommended
- BI-RADS 4: There is an undetermined or suspicious abnormality
- BI-RADS 5: There is an abnormality suggestive of cancer
Doctors use this classification to determine the next steps and if closer monitoring or specific tests are warranted.
Important detail on ultrasound
Breast ultrasound is not a test used for cancer screening and is not a replacement for mammogram. This method for exploring the breast is used to further specify the nature of an abnormality that was first identified, usually during a mammogram.
Breast ultrasound is complementary to a mammogram. The only test that can provide a definitive breast cancer diagnosis is biopsy. The preceding tests are no more than steps to determine whether further investigation is warranted. If you have a concerning symptom, talk to your doctor, who will guide you through the next steps.
If you have questions or concerns about breast cancer, we are here for you before, during and after diagnosis. Call our confidential line: 1 855 561-PINK.
We would like to thank the Ordre des technologues en imagerie médicale, en radio-oncologie et en électrophysiologie médicale du Québec (OTIMROEPMQ) for its assistance in writing this article.
BIBLIOGRAPHY
D’Orsi, CJ, EA Sickles, EB Mendelson, EA Morris, et et al. « ACR BI-RADS® Mammography. In: ACR BI-RADS® Atlas, Breast Imaging Reporting and Data System ». American College of Radiology, 2013.
Fondation cancer du sein du Québec. « Diagnostic cancer du sein ». Ruban rose (blog). Consulté le 14 octobre 2021. https://rubanrose.org/minformer/depistage-et-diagnostic/diagnostic/.
Fondation cancer du sein du Québec. « Le cancer du sein associé à la grossesse », 2018. https://rubanrose.org/wp-content/uploads/2020/06/2019__depliant_grossesse_fr.pdf.
Gouvernement du Québec. « Les indications de l’échographie mammaire ». Ministère de la santé et des services sociaux, 2017, 2.