When is sentinel lymph node biopsy recommended for breast cancer?

Lymph fluid from a breast tumour usually travels first to a small group of underarm nodes called sentinel nodes. During surgery, the team identifies and removes these nodes so a laboratory can check them for cancer cells.

The result helps the team understand whether cancer has reached the lymphatic system and whether further underarm treatment or additional therapy should be considered. The recommendation can change with tumour size, biology, previous breast treatment, pregnancy, planned surgery, and whether nodes already look involved.

Ask whether the biopsy will be done during breast-conserving surgery or mastectomy, how the sentinel nodes will be located, and what happens if cancer cells are found. Tell the team about previous operations, lymphatic problems, allergies, pregnancy, and medicines that affect bleeding.

Discuss possible temporary soreness, bruising, arm stiffness, numbness, or swelling, and learn the recommended arm exercises and wound care. Background is available in [Breast Cancer](/conditions/breast-cancer/) and [Sentinel Lymph Node Biopsy](/treatments/diagnostics-and-staging/sentinel-lymph-node-biopsy/).

After the procedure, contact the surgical team for increasing redness, warmth, drainage, fever, worsening pain, a rapidly enlarging swelling, or reduced arm movement. Sudden breathlessness or chest pain needs urgent medical assessment.

Do my examination and imaging make sentinel node biopsy appropriate? How many nodes may be removed? How will the result affect the next treatment decision? What arm symptoms should I report, and when will the pathology result be discussed?