Sentinel Lymph Node Biopsy

Sentinel lymph node biopsy removes the first draining lymph node or nodes for laboratory examination.

Before or during surgery, the team injects a tracer near the tumour or previous biopsy site. The tracer helps identify the lymph node that receives drainage first. The surgeon makes a small incision, removes the identified node or nodes and sends them to the laboratory. It may be performed alongside surgery to remove the main cancer.

The procedure is generally designed to examine fewer lymph nodes than a wider node operation, but it still has surgical and tracer-related risks. The mapping may not identify a sentinel node, and laboratory testing can occasionally miss a small area of cancer. Your team interprets the result alongside the tumour findings, examination and imaging.

If cancer cells are found, the result helps describe whether nearby lymph nodes are involved. The team may discuss further node surgery, radiation treatment, drug treatment, closer follow-up or no additional node procedure, depending on the cancer type and the amount and pattern of disease found. A positive node does not by itself determine every part of treatment.

Tell the team about allergies, pregnancy, medicines that affect bleeding, prior operations and any swelling or infection near the planned area. Ask whether the biopsy will be done at the same time as cancer surgery and how results will be communicated.

It is commonly considered when assessing certain breast cancers and melanomas that have not already been shown to involve nearby lymph nodes. Suitability depends on the tumour, previous treatment, node examination and the information that the result would add to care planning.

The tracer is placed near the relevant area, and the surgeon uses the mapping signal to locate the sentinel node. Anaesthesia may be local, regional or general depending on the wider operation. The incision is closed after node removal, and you are monitored as the anaesthetic wears off. The laboratory examines the tissue before the results appointment.

The incision can feel tender or tight while it heals. Follow the specific instructions on dressings, washing, activity and pain relief. Contact the surgical team if redness spreads, drainage increases, fever develops, or swelling and pain are getting worse rather than settling.

Possible complications include bleeding, infection, a fluid collection, numbness, stiffness, allergic reaction to the tracer and swelling of the limb. Lymphoedema can occur even after a limited node procedure. The biopsy samples selected nodes, so it is not a complete examination of every lymph node in the body.

Depending on the situation, the team may use clinical examination and imaging, perform a wider lymph node operation, or decide that no node procedure is needed. The right option depends on how the result would change treatment planning.

Ask which tracer will be used, what type of anaesthesia is planned, whether the biopsy is combined with another operation and when you can expect the pathology discussion. Share any history of allergy, arm or leg swelling, blood-thinning medicine or previous treatment in the region.