From the Guidelines
For a new breast lump, the initial imaging should be a diagnostic mammogram and ultrasound of the affected breast, with bilateral mammography recommended for complete evaluation, especially for baseline comparison and to assess for any occult abnormalities in the contralateral breast. The choice of initial imaging modality depends on the patient's age, with diagnostic mammography or DBT preferred for women aged 40 years or older 1, and breast US preferred for women younger than age 30 years 1. For women aged 30 to 39 years, either US or diagnostic mammography or DBT can be used for initial evaluation 1.
The importance of correlation between imaging and the palpable area of concern cannot be overstated, as any highly suspicious breast mass detected by imaging should be biopsied, irrespective of palpable findings 1. Additionally, any highly suspicious breast mass detected by palpation should be biopsied, irrespective of imaging findings 1. The combination of mammography and ultrasound provides complementary information, with mammography detecting microcalcifications and architectural distortions that may indicate cancer, and ultrasound helping distinguish between solid masses and fluid-filled cysts, particularly in dense breast tissue 1.
Key considerations in the imaging workup of a palpable breast mass include:
- The patient's age and breast density
- The presence of any high-risk factors, such as family history or genetic predisposition
- The clinical examination findings, including the size, location, and characteristics of the palpable mass
- The need for bilateral imaging to assess for any occult abnormalities in the contralateral breast. Prompt imaging is crucial as it guides further management decisions, including the potential need for biopsy, and ultimately impacts morbidity, mortality, and quality of life outcomes.
From the Research
Imaging Modalities for Breast Lump Evaluation
The evaluation of a new breast lump typically involves imaging studies to determine the nature of the lump. The choice of imaging modality depends on various factors, including the patient's age, breast density, and clinical presentation.
- Mammography: Mammography is commonly used as the initial imaging modality for women over 40 years of age 2. However, its sensitivity is lower compared to other modalities, with an overall sensitivity of 54.5% (range 27%-86.8%) 3.
- Ultrasound: Ultrasound is often used as the initial imaging modality for women under 30 years of age 2. It has a higher sensitivity than mammography, with an overall sensitivity of 67.2% (range 26.9%-87.5%) 3.
- Magnetic Resonance Imaging (MRI): MRI has the highest sensitivity among all imaging modalities, with an overall sensitivity of 94.6% (range 85.7%-100%) 3. It is particularly useful in evaluating lesions in women with dense breasts or those at high risk of breast cancer 4.
Bilateral Imaging
The decision to perform bilateral imaging depends on the clinical presentation and the patient's risk factors.
- Unilateral lump: If the lump is unilateral, imaging of the affected breast is typically performed first. If the findings are suspicious or highly suggestive of malignancy, imaging of the contralateral breast may be considered 2.
- Bilateral imaging: Bilateral imaging may be considered in women with a high risk of breast cancer, those with dense breasts, or those with a history of breast cancer 4.
Recommendations
Based on the available evidence, the following recommendations can be made:
- Women under 30 years of age: Ultrasound is usually the appropriate initial imaging modality 2.
- Women between 30-39 years of age: Ultrasound, diagnostic mammography, or tomosynthesis may be used as the initial imaging modality 2.
- Women over 40 years of age: Diagnostic mammography and tomosynthesis are usually the appropriate initial imaging modalities 2.
- High-risk women or those with dense breasts: MRI may be considered as an additional imaging modality 4.