The benefits of Ultrasound for Breast Cancer Screening

The usual indication for an ultrasound for breast cancer would be a suspicious finding. By the way, ultrasound is also sometimes known as ‘sonography’.

Specialists may discover a suspicious finding on mammogram or as a palpable lesion (or lump) in a clinical breast exam.

Often an ultrasound is useful to evaluate further for a diagnosis. Thus, ultrasound imaging tends to be useful in breast cancer screening as a ‘second look’ or follow up tool.

However, just because a woman is sent for a follow-up ultrasound, there is no reason to be anxious about breast cancer.

Ultrasound is particularly helpful in distinguishing between a solid mass and a fluid-filled cyst, which is what a majority of breast lesions turn out to be.

Ultrasound is also useful in finding very small lesions that are too small to be felt at a clinical exam.

The ultrasound picture shows a dark area just below the skin. I’m not certain what it is. In this case, inflammation is more likely than cancer.

How do Ultrasounds Work?

Ultrasound imaging uses high-frequency sound waves to form an image or a ‘sonogram‘.

The sound waves are harmless and pass through the breast and bounce back or ‘echo‘ from various tissues to form a picture of the internal structures.

An unexpected ‘echo‘ means that there is a solid nodule of some kind within the tissue. There is no radiation involved in ultrasound imaging, which makes it a preferred method of diagnostic imaging for pregnant women.

I have created a new page with more up-to-date information on Ultrasounds. We look at the benefits and more. However, this page is still pretty great.
Dr Halls

Ultrasound and breast density

Specialists will often use ultrasound to screen women with high breast density because mammograms can be difficult to interpret in this group.

For this reason, ultrasound is frequently a ‘first’ diagnostic imaging method for women under 35.

Whether or not an ultrasound can ‘stand-alone’ as a screening method versus combining it with mammography or MRI is still a subject of debate.

At present, there is no study which definitively proves that ultrasound screening alone lowers mortality rates for breast cancer, unlike mammography, which does.

In the past, a woman with dense breast tissue and ‘no abnormalities seen’ on mammogram would not go on to have an ultrasound.

However, more and more often, when mammograms have very dense tissue, medics will recommend an ultrasound too.

Combining ultrasound for Breast Cancer with MRI or biopsy

Research shows that the combination of ultrasound with Magnetic Resonance Imaging (MRI) is a particularly good combination in follow-up evaluation of lesions found on mammography.

The detail of the MRI greatly assists in diagnostic and treatment decisions. Ultrasound is also very useful in guiding the needle during a follow-up biopsy.

Above is a hypoechoic solid nodule. Could be benign, could be cancer. I would probably ask to biopsy it.

Screening and detection rates using ultrasound

The discovery rate of malignant cancer using breast cancer screening methods is actually very low.

So, for example, the rate of detecting breast cancer on a mammogram is about 5 cancers in every thousand women screened.

Ultrasound alone for breast cancer screening detects slightly fewer malignancies. This tends to suggest that mammography is slightly more reliable in the detection of breast cancer.

Unfortunately, I have to stress here that the combination of mammography, ultrasound and even MRI can not completely exclude the possibility of breast cancer.

Indeed, up to 3% of women with suspicious lesions but negative mammograms and ultrasounds may still have breast cancer.

The expense and Practical Considerations of Ultrasound for Breast Cancer Screening

Ultrasound imaging is not really any more expensive than mammography, and in many ways, it is more convenient.

The problem is, almost all suspicious ultrasound findings are inconclusive and end up being referred for a biopsy anyway.

So, this must be weighed against the cost and effectiveness of mammographic screening as a whole, which tends to provide better assurance to the nature of a lesion with respect to the need for a biopsy.

Typical categories of breast ultrasound results

Abnormal results of ultrasound will tend to fall into four categories.

So, a radiologist can usually tell if the echoes are caused by benign fibrous nodules (breast fibrocystic disease, papillomas, fibroadenomas).

Of slightly greater concern are sonographic indications of a ‘complex cyst‘.

The third and fourth informal categories are more worrying and indicate an increase in the likelihood of cancer. These are suspicious lesion, and lesion highly suggestive of cancer.

What can an ultrasound reveal about a potential breast cancer lesion?

A sonogram gives a good indication of the liquid or solid nature of a lesion, or perhaps a combination.

Liquid masses (cysts) tend to be darker in color and homogeneous.

An experienced radiologist gains a feel for what the different textures of a sonogram tend to represent. The shape of a lesion and also its margin (the characteristics of its ‘edges’) are also quite evident on sonograms.

The above factors help determine whether a lesion is cancerous or benign (cancerous lesions tend to have jagged edges).

Breast cancer lesions also tend to be somewhat random in shape, but not always. Benign fibroadenomas are usually round or oval.

However, ultrasound is not a definitive test, and tissue analysis via biopsy is usually necessary. Even when ultrasound suggests the presence of a fibrous nodule or complex cyst, a biopsy is still justified. Up to 15% of these types of growths end up being malignant.

Any ‘echoes’ on the sonogram (a change from the sound on its way back compared to on the way in) indicates that a solid nodule of some kind has blocked the path of the sound wave.

Analysis of the solid nodules on a breast sonogram requires considerable expertise and can give further clarity as to the benign or malignant nature of the lesion.

Let’s go over some Q&A’s …

Why is a breast ultrasound performed?

A breast ultrasound will be performed if you or your doctor discovered a suspicious mass in your breast.

The ultrasound will help determine the location and the size of the mass. Whilst a breast lump may be frightening, approximately 4 out of 5 breast lumps are benign (non-cancerous).

What are some risks of a breast ultrasound?

Because this imaging technique uses absolutely no radiation, a breast ultrasound carries no risks what-so-ever.

Radiation tests are not safe for pregnant women, so an ultrasound is the method of breast exams for women who are pregnant.

In fact, the test involves the same kind of ultrasound waves used to monitor the development of a fetus.

How do I prepare for a breast ultrasound?

Preparation for a breast ultrasound is minimal. Because you’ll need to expose your breasts during the test, it’s best to wear a two-piece outfit to your appointment.

Also, don’t apply any creams, lotions, or other cosmetics on the skin of your breasts. This can interfere with the test procedure.

What are some of the results of a breast ultrasound?

The images from a breast ultrasound are in black and white. Cysts, tumors, and growths will appear dark on the scan.

However, just because there is a dark spot on your ultrasound, it does NOT mean that you have breast cancer. The majority of breast lumps are noncancerous, so more testing is needed to determine whether the lump is malignant.

Several conditions that can cause benign breast lumps include adenofibroma, fibrocystic breast disease, intraductal papilloma, and mammary fat necrosis.

References

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