Ultrasound Use in Breast Cancer Diagnosis

Ultrasound is being used with increasing frequency to help diagnose breast cancer. For example, an ultrasound can target a suspicious mammographic finding, further evaluating whether it is solid like cancer or fluid-filled with smooth edges like a cyst.1 It can also be used to localize a mass during a biopsy procedure.

Ultrasound of the Breast

Ultrasound, or sonogram, is a non-invasive procedure that uses high-frequency sound waves deflecting off of tissue to a detector, which creates a two-dimensional image on a screen in real-time. Benefits of ultrasound are that it does not use radiation and it can be done in an outpatient setting.

Ultrasound can be done with in a “Doppler” mode, which measures blood flow toward or away from the sound waves and depicts it with color on the screen. This may be used to evaluate blood flow into or around a mass, as cancers tend to be highly vascularized.

The ultrasound has several important uses of note specifically for breast cancer:[1]

Uses of Ultrasound

Supplement to Mammography in Breast Cancer Screening Mammograms are unable to characterize all breast lesions. Ultrasound can further evaluate lesions found on mammogram, as solid or cystic.
Ultrasound-Guided Breast Biopsy The real-time image on ultrasound allows a biopsy procedure to be performed while directly visualizing the needle enter into a tumor and take a sample, which increases the accuracy of the procedure.

The Ultrasound Machine

Ultrasound is an extremely useful tool in many areas of medicine. Perhaps the most familiar to people is its use during pregnancy to evaluate the developing fetus. The ultrasound is a simple piece of machinery that can be used to gather a large amount of data. It is composed of a transducer attached to a cord, and a computer unit that has a screen and a large keyboard.

The transducer can have several different shapes depending on what it is used for. In general, it is a plastic wand that looks a bit like a small microphone and is attached to the computer unit via a cord. High frequency sound waves are emitted through the probe into tissue, in this case the breast. The sound waves deflect back to the probe and as they are detected, they travel through the cord and this information is used to create a real-time image on the screen. Ultrasound can distinguish between soft tissues, fluid, solid masses and even calcifications, which are seen as shadows on the screen. With an understanding of anatomy, the technician and physician can use this data to understand what the ultrasound image is showing.

The procedure

When you arrive for your procedure you will be asked to undress from the waist-up. You will be given a smock and asked to lie on the examination table on your back with your arms above your head.

A small amount of gel is then placed on the breast, which acts as a medium for the sound waves to travel through before they penetrate the skin, creating a clearer image on the screen. The technician will then place the transducer on your breast and apply some pressure, moving it around the breast to look at different areas.  The technician may pause at the area of concern and freeze the screen, take a picture of the image before continuing to looking at other areas, or even record the entire exam. These images can be printed and shown to your ordering physician, or the radiologist can watch the recording of the exam to determine what it has found.  The exam typically takes about thirty minutes.

The Benefits of Ultrasound as an Adjunct for Breast Cancer Screening

There are several benefits of using ultrasound as an adjunct for breast cancer screening. It is non-invasive, can be done as an outpatient, does not use radiation and is widely available. The real-time image also makes it useful during biopsies, as the mass being sampled can be directly visualized during the entire procedure. Ultrasound is often combined with mammography, as it can further evaluate the structure and content of a potentially suspicious lesion. One study reported that mammogram missed up to 35% of malignancies in a high-risk study population, but when combined with ultrasound helped to diagnose twelve more malignancies that may have gone undiagnosed.[2]

Are There Limits to Ultrasound?

Ultrasound is an excellent tool, but should not take the place of routine screening mammography. Women should continue to have a mammogram annually, or as directed by their doctor, based on risk factors and age.[3] It is important to understand that if your doctor recommends for you to have an ultrasound or biopsy, it does not necessarily mean that you have cancer. Your doctor just wants to eliminate the worst possible scenario.

1 Ibid

2  Schwenk, T. (2008). Ultrasound Plus Mammography for Breast Cancer Screening. Journal Watch General Medicine .

3  New Guidance Issued for Breast Screening. (2011). Contraceptive Technology Update .

This article was originally published on July 27,2012 and last revision and update of it was 9/2/2015.