From the Guidelines
Ultrasound is the best initial imaging tool to assess axillary lymphadenopathy. It offers excellent visualization of superficial lymph nodes with high sensitivity for detecting abnormalities while being widely available, cost-effective, and radiation-free 1. When performing an ultrasound evaluation, suspicious features to look for include lymph node size greater than 1 cm, loss of fatty hilum, rounded shape (short-to-long axis ratio >0.5), irregular borders, cortical thickening, and increased vascularity on Doppler imaging.
Key Points to Consider
- Ultrasound is the preferred initial imaging modality for assessing axillary lymphadenopathy due to its high sensitivity and specificity 1.
- MRI provides superior soft tissue contrast and can better assess the relationship between lymph nodes and surrounding structures, making it a valuable tool for further characterization after ultrasound 1.
- CT scanning may be appropriate when evaluating for metastatic disease or when planning for surgery, while PET-CT is valuable for detecting metabolically active nodes in cancer staging.
- Ultrasound also allows for simultaneous fine needle aspiration or core biopsy if tissue sampling is needed for definitive diagnosis, with US-guided FNA being a well-tolerated low-risk procedure that can accurately confirm metastatic disease in a suspicious lymph node 1.
Clinical Context Considerations
- The choice of imaging modality should ultimately be guided by the clinical context, including the patient's history, physical examination findings, and suspected underlying pathology 1.
- The risk of cancer in women with no personal history of breast cancer is low but increases with age, and imaging most often entails a combination of different imaging modalities followed by surgical consultation or follow-up 1.
From the Research
Imaging Tools for Axillary Lymphadenopathy
The best imaging tool to use for assessing axillary lymphadenopathy can depend on various factors including the patient's specific condition, the availability of equipment, and the expertise of the practitioner. However, based on the provided studies, the following points can be considered:
- Ultrasound (US): US is widely recognized for its usefulness in assessing axillary lymphadenopathy. It offers high resolution, is fast and accurate, and allows for US-guided fine-needle aspiration biopsy (FNAB) of pathological nodes, which increases specificity 2.
- US-Guided Fine Needle Aspiration (FNA) and Core Needle Biopsy (CNB): These techniques have been shown to be highly effective in diagnosing axillary lymphadenopathy. A study found that the diagnostic performance of FNA, CNB, and FNA + CNB was excellent, with high sensitivity, specificity, and accuracy 3.
- Comparison of US-FNA and US-CNB: A meta-analysis comparing the diagnostic accuracy of US-FNA and US-CNB in diagnosing axillary lymph node metastasis found that US-CNB was superior to US-FNA in terms of sensitivity, although both had high specificity 4.
- Other Imaging Modalities: Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are also used for assessing axillary lymph nodes, but they are restricted to imaging only and do not offer the possibility of guided biopsy like US does 2.
Key Findings
- US-guided FNA and CNB are valuable tools in the diagnosis and management of axillary lymphadenopathy 3, 4.
- The choice between US-FNA and US-CNB may depend on the specific clinical scenario and the expertise available, considering that US-CNB has higher sensitivity but also higher complication rates compared to US-FNA 4.
- Axillary ultrasound, including US-FNA and US-CNB, plays a significant role in the preoperative staging of breast cancer and can help in identifying patients who may not require sentinel lymph node biopsy or axillary node dissection 5, 6.