A sentinel node biopsy in breast cancer is primarily used to determine what?

• A. Distant organ metastasis
• B. Lymph node involvement in the axilla
• C. Tumor receptor status
• D. Primary tumor size

Answer: (B)

The main concept is that a sentinel lymph node biopsy is used to assess whether breast cancer has spread to the regional lymph nodes, specifically in the armpit (axilla). The sentinel node is the first lymph node that drains the tumor, so if cancer cells are present there, it suggests nodal involvement. Sampling and examining this node helps stage the disease and guides decisions about further lymph node surgery and adjuvant therapy, while often avoiding a full axillary dissection if the sentinel node is negative.

This test does not determine distant metastasis, which is assessed with imaging and systemic evaluation; it also does not measure tumor receptor status or primary tumor size, which are determined by biopsy and pathology of the tumor itself or imaging of the tumor, respectively.