From the Guidelines
Breast ultrasound is a valuable supplemental screening tool for breast cancer, particularly for women with dense breast tissue or high risk factors, but it is not recommended as a primary screening method for the general population.
Role of Ultrasound in Breast Cancer Screening
Ultrasound should be used in conjunction with mammography, which remains the gold standard for breast cancer screening.
- For women with dense breasts, adding ultrasound to mammography can increase cancer detection rates by approximately 3-4 additional cancers per 1000 women screened 1.
- The procedure is non-invasive, uses no radiation, and typically takes 15-30 minutes to complete.
- Women should begin discussing breast cancer screening with their healthcare provider by age 40, with recommendations varying based on individual risk factors.
Limitations and Benefits of Ultrasound
Ultrasound is particularly useful because it can distinguish between solid masses and fluid-filled cysts, which mammography cannot always differentiate.
- However, ultrasound has limitations including higher false-positive rates, operator dependence, and inability to detect microcalcifications, which are sometimes early signs of breast cancer 1.
- Women with a family history of breast cancer, BRCA gene mutations, or previous radiation therapy to the chest may benefit most from supplemental ultrasound screening 1.
Recommendations for Supplemental Screening
For women with elevated risk who would qualify for but cannot undergo breast MRI, adjunctive screening with ultrasound should be considered 1.
- For women with elevated risk limited to increased breast density, ultrasound can be considered for adjunctive screening, after weighing benefits and risks 1.
- The American College of Radiology recommends annual mammographic screening beginning at age 40 for women of average risk, and supplemental screening with contrast-enhanced breast MRI for women with genetics-based increased risk or a history of chest or mantle radiation therapy at a young age 1.
From the Research
Role of Ultrasound in Breast Cancer Screening
The use of ultrasound in breast cancer screening has been studied extensively, with evidence suggesting its potential benefits in certain populations.
- Ultrasound can detect cancers not identified on mammography in asymptomatic women with dense breast tissue 2, 3.
- Supplemental screening ultrasound may be beneficial to women with dense breast tissue and intermediate or average risk for breast cancer 2.
- The addition of screening ultrasound to mammography in women at increased risk of breast cancer resulted in a higher cancer detection yield, but also an increase in false-positive findings 4.
- Combined screening with mammography and ultrasound improved cancer detection in women at average risk for breast cancer, particularly in those with dense breasts 5.
Benefits and Limitations of Ultrasound
The benefits of ultrasound in breast cancer screening include:
- Improved detection of cancers in women with dense breast tissue 2, 3.
- Potential alternative to magnetic resonance imaging (MRI) for women with socioeconomic or medical restrictions 2. The limitations of ultrasound include:
- Substantial rate of false-positives 2.
- Increased cost and limited resource availability 2.
- Need for additional clinical experience and improved patient selection criteria to address these limitations 2.
Comparison with Other Screening Methods
- Ultrasound has been compared to MRI in breast cancer screening, with MRI showing higher sensitivity and specificity 4.
- The combination of mammography and ultrasound has been shown to improve cancer detection compared to mammography alone 5.
- The role of ultrasound in breast cancer screening needs to be re-examined in light of its efficacy, utility, and feasibility as a screening tool 6.