What is the recommended next step for a 47-year-old female patient with a history of invasive lobular carcinoma (breast cancer) who has a left supraclavicular lymph node that has grown from 6mm to 8mm over 1 year?

Tissue Diagnosis of the Supraclavicular Lymph Node is Mandatory

In a 47-year-old woman with a history of invasive lobular carcinoma who has a left supraclavicular lymph node that has grown from 6mm to 8mm over 1 year, the next step is immediate tissue diagnosis via fine needle aspiration or core needle biopsy to determine if this represents metastatic disease. 1

Why This Node Demands Urgent Evaluation

• A supraclavicular lymph node in a patient with prior breast cancer represents N3c disease (metastases in ipsilateral supraclavicular lymph nodes), which is Stage IIIC disease if confirmed to be metastatic breast cancer 1
• Growth of any lymph node over time in a cancer patient—even modest growth from 6mm to 8mm—is highly suspicious for malignant involvement and cannot be observed 2
• Invasive lobular carcinoma has a distinct propensity for occult spread and can present with lymph node metastases even when imaging of the breast appears normal 3, 4

The Diagnostic Algorithm

Step 1: Obtain tissue diagnosis immediately

• Perform image-guided core needle biopsy or fine needle aspiration of the supraclavicular node as the first-line diagnostic test 1, 2
• Core biopsy is preferred over FNA as it provides more tissue for histological subtyping, hormone receptor status (ER/PR), and HER2 testing 1

Step 2: If malignancy is confirmed, complete staging workup

• Obtain CT chest/abdomen/pelvis or PET-CT to identify extent of disease and rule out distant metastases 2
• Examine all other lymph node basins including contralateral supraclavicular, axillary, and inguinal regions 2
• Perform bilateral mammography with ultrasound, as lobular carcinoma can be bilateral and multifocal 1, 5, 6

Step 3: Determine receptor status on the node biopsy

• Test for ER, PR, and HER2 status on the lymph node tissue, as receptor status can change from the primary tumor 1
• This information is critical for treatment planning if metastatic disease is confirmed 1

Critical Pitfalls to Avoid

• Do not observe this node: A growing lymph node in a cancer patient requires tissue diagnosis, not surveillance 1
• Do not assume it is benign: Invasive lobular carcinoma is notorious for producing subtle clinical findings and can metastasize with minimal or no radiographic evidence of recurrent breast disease 3, 4
• Do not delay imaging: If the node is positive for metastatic breast cancer, the patient needs immediate staging to determine if this is isolated regional disease (potentially curable with aggressive locoregional therapy) versus distant metastatic disease 1

Special Considerations for Invasive Lobular Carcinoma

• Lobular carcinoma has a higher false-negative rate on mammography (19%) compared to ductal carcinoma due to its growth pattern of single-file cells that infiltrate without forming dense masses 4
• Ultrasound should be specifically considered in follow-up of lobular carcinomas because of their subtle radiographic appearance 1
• Multifocal, multicentric, and bilateral disease occur more frequently with lobular histology 5, 6
• At diagnosis, 44% of invasive lobular carcinomas already have axillary lymph node metastases, indicating aggressive lymphatic spread 4

If Metastatic Disease is Confirmed

• Supraclavicular nodal involvement (N3c) with no distant metastases may still be treated with curative intent using systemic therapy followed by locoregional treatment including surgery and radiation 1
• Radiation to the supraclavicular region is indicated for N3 disease 1
• Systemic therapy selection depends on hormone receptor and HER2 status of the metastatic tissue 1