A sentinel node biopsy (SNB) is a clinical procedure in which the sentinel lymph node is removed and tested for the presence of cancer cells. If the result of an SNB is negative, it can suggest that the cancer has not spread to the lymph nodes or other parts of the body.

A positive result for an SNB indicates the presence of cancerous cells in the sentinel lymph node and possibly in other lymph nodes in the surrounding area. The information gained from SNB is crucial for doctors in staging the cancer and devising a customized treatment plan.