Study: How do ultrasound and mammography compare in breast cancer screening?


This article is most relevant for:
Young women at high risk for breast cancer with limited access to mammography and MRI is not easily accessible

This article is also relevant for:

Checked People with a genetic mutation linked to cancer risk

Checked Previvors

Checked Women under 45

Checked Women over 45

Checked Special populations: Women with dense breasts; women at high risk for breast cancer


Be a part of XRAY

Relevance: Medium-High

Relevance

Strength of Science: High

Strength of Science

Research Timeline: Post Approval

Research Timeline

Rating Details

Printer Friendly Page

Mammography has been shown to reduce breast cancer deaths; however, women in developing countries don’t have easy access to mammography. Ultrasound screening, on the other hand, is portable and less expensive, and could be an alternative to mammography. This study compared mammography to ultrasound in women with dense breasts and found the two techniques have similar cancer detection rates, although the false positive rate is higher with ultrasound. (02/16/16)

 

Contents

At a glance                  Questions for your doctor
Findings               In-depth                
Clinical trials Limitations
Guidelines Resources and references


STUDY AT A GLANCE

What is this study about?

The study looks at the effectiveness of ultrasound as compared to mammography for breast cancer screening.

Why is this study important?

In general, the number of breast cancer cases worldwide is increasing. Women in developing countries do not have easy access to mammography, and some lack breast cancer screening entirely. Ultrasound has many advantages:  it does not use ionizing radiation, the machinery is portable and not as expensive as mammography, making it a more viable alternative for women in developing countries.

What did this study find?

  • A total of 111 breast cancers were found in three years. (The study included a total of 7473 breast cancer screens in patients at increased risk for breast cancer.) Of these 111 breast cancers, 58 were found through ultrasound and 59 were found through mammography.
  • There were more false positives among the patients who got ultrasounds compared to patients who got mammography. The recall rate for ultrasounds was about 11% while the recall rate for mammograms was about 9%.

What does this mean for me?

Ultrasound and mammography have similar cancer detection rates, although there are more false positives found through ultrasound. However, this finding does not mean that ultrasound should replace mammography. According to the study authors, “…these results suggest that screening [ultrasound] could be a viable alternative to mammography in countries lacking organized screening, particularly with availability of low-cost, portable [ultrasound] systems. Where mammography is available, [ultrasound] should be seen as a supplemental test for women with dense breasts who do not meet high-risk criteria for screening MRI and for high-risk women with dense breasts who are unable to tolerate MRI.National guidelines recommend that women who have mutations in BRCA or other genes that increase their risk of breast cancer undergo increased surveillance for breast cancer using both MRI and mammography. It is important to remember that this study looked at women at high risk for breast cancer. The results may not apply to women with an average lifetime risk of breast cancer.

(back to top)

Expert Guidelines

The National Comprehensive Cancer Network (NCCN) establishes guidelines for breast cancer screening and cancer care in the U.S. For women with a BRCA1 or BRCA2 mutation, the guidelines recommend the following:

  • Learning to be aware of changes in breasts beginning at age 18
  • Clinical breast exam every 6-12 months beginning at age 25
  • Annual breast MRI with contrast (or mammogram if MRI is unavailable) beginning at age 25 
  • Annual breast MRI with contrast and mammogram at ages 30-75
  • Consider 3D mammography if available
  • Screening after age 75 should be considered on an individual basis
  • Consider participation in an imaging or screening clinical trial

For women without a BRCA1 or BRCA2 mutation, with increased risk (a lifetime risk for breast cancer of 20% or more), the guidelines recommend the following screening:

  • Have clinical exams every 6–12 months, starting when you are identified as being at increased risk, but not before age 21
  • Obtain a referral to genetic counselor or similarly trained health care provider, if you haven’t already done so.
  • Start annual mammography screening 10 years earlier than the age of the youngest family member who has been diagnosed with breast cancer, but not prior to age 30. Consider getting a 3-D mammogram.
  • Begin annual breast MRI 10 years earlier than the age of the youngest family member who has been diagnosed with breast cancer, but not prior to age 25.
  • Consider recommended risk reduction strategies, such as preventive hormonal medications or risk-reducing surgeries that remove the breasts or ovaries.
  • Develop breast awareness and report any changes to your health care providers

(back to top)

Questions To Ask Your Health Care Provider

  • I carry a mutation in a gene that increases cancer risk. How does this change the breast cancer screenings I should receive?
  • I have dense breasts—can I get ultrasounds in addition to mammograms?
  • Will my health insurance cover breast MRI? If they do not cover it, are there financial assistance programs? 
  • I have difficulty accessing mammograms. Can I get ultrasounds instead?
  • I have a medical reason why I cannot have MRI, should I get ultrasounds?

Open Clinical Trials

The following breast cancer screening clinical trials are currently enrolling participants:

IN DEPTH REVIEW OF RESEARCH

Study background:

Previous work has shown that mammograms reduce the number of breast cancer deaths. In women from age 40-49, researchers have seen a 15% reduction in breast cancer deaths; a 22% reduction has been seen in women from age 50 -74. It is believed that older women benefit more from mammography because their breasts are not as dense as those of younger women. In addition to ultrasound’s portability and cost benefits, the quality of ultrasound images are not as limited by breast density as are mammography images.

In January 2016, Wendie Berg and colleagues at the Magee-Womens Hospital of University of Pittsburgh Medical Center and other institutions published a study in the Journal of the National Cancer Institute that compared all aspects of cancer detection from ultrasound and mammography.

What researchers of this study wanted to know:

Is ultrasound a viable alternative to mammography?

Population(s) looked at in the study:

This study included 2,662 women who did not have breast cancer, but did have dense breasts. These women also had to have one other risk factor for breast cancer (for example, a BRCA mutation, an atypical breast biopsy, or high risk scores through the Gail test for Breast Cancer Risk Assessment).

Study findings: 

  1. One hundred and eleven breast cancers were found in  a three- year period from a total of 7473 breast cancer screens in patients at increased risk for breast cancer. Of these 111 breast cancers, 58 were found through ultrasound and 59 were found through mammography.
  2. It took 129 ultrasound screens to detect 1 cancer.
  3. It took 127 mammogram screens to detect one cancer.
  4. 89 of the breast cancers were invasive. Of the 89 invasive cancers, 53 were found by ultrasound and 41 were found by mammography.
    • Fifty-three of the 58 cancers found by ultrasound were invasive; the other five were ductal carcinoma in situ (DCIS). Forty-one of the 59 cancers found by mammogram were invasive; the other 18 were DCIS. These results indicate that ultrasound screening may be better able to identify invasive cancers.
  5. There were more false positives found in patients who got ultrasounds compared to patients who got mammograms. The recall rate for ultrasounds was about 11% while the recall rate for mammograms was about 9%.
    • The biopsy rate for the women who got called back based on their ultrasound results was about 6% while it was 2% for women who got called back based on their mammogram results.

Limitations:

In order to participate in this study, women had to have dense breasts and at least one other risk factor for breast cancer, meaning that they were all at greater risk for breast cancer than women in the general population. Therefore, the results of this study may be more applicable to young breast cancer survivors. Had study participants been at average risk for breast cancer, the results may have been different. For now, the results apply only to women at high risk of breast cancer. 

Conclusions:

This study suggests that ultrasound may be a viable alternative to mammography for women in countries that do not have access to mammography. Ultrasound should not be a replacement, however, for women who can access mammography.  The researchers saw that more invasive cancers were detected by ultrasound as compared to mammography; however, they write, “a larger study is needed to statistically support greater sensitivity of ultrasound to invasive cancers.”

Posted 2/16/16

3 likes

Back to XRAY Home

Search XRAY studies and articles

Back to XRAY Home

FORCE:Facing Our Risk of Cancer Empowered