Sentinel node biopsy involves removing the first lymph nodes (or nodes) in the armpit to which cancer cells are likely to spread from the breast.
Sentinel node biopsy is usually done during breast surgery (breast conserving surgery or mastectomy). Sometimes it may be performed as a separate procedure.
Although some women may have one sentinel node, some may have two or three sentinel nodes. Usually the sentinel node is in the armpit (axilla). Sometimes the sentinel node is in another part of the body - for example, in the chest between the ribs under the breast or above or under the collarbone
There are different ways of finding the sentinel node. The best way is to use a combination of two substances - one is a low-grade radioactive fluid (isotope) and the other is a blue dye. The dye and radioactive fluid show the surgeon to which lymph node(s) breast cancer cells are most likely to travel.
Sometimes, either the blue dye or the radioactive fluid alone is used to look for the sentinel node
Sentinel node biopsy is associated with a lower risk of arm problems than axillary dissection. This means that the risk of numbness, shoulder stiffness and lymph oedema is lower than with axillary dissection.
There’s a small risk of allergic reaction to the radioactive fluid or blue dye used to find the sentinel node. Allergic reactions are usually mild and easily treatable.
Rarely, women may experience a severe allergic reaction (less than 1 in 5000 cases). A doctor may decide not to use the blue dye for sentinel node biopsy if there’s reason to think a woman may be at significant risk of allergy to the blue dye.
If blue dye is used to find the sentinel node, the urine may turn blue for 24 hours after surgery. The skin of the breast may also become blue but this will fade with time.
Also, there are general potential complications like any other surgery and these are (not limited to) a low risk of infection or bleeding.
Axillary clearance of the lymph nodes, also called axillary dissection, is a surgical procedure that involves the removal of the lymph nodes from the axilla (arm pit).
Because the number of lymph nodes in the armpit varies from person to person, the number of lymph nodes removed and the length of the operation will be different for each woman.
The potential complications following axillary surgery are (not limited to):
- Seroma: fluid collection under the armpit. This may need to be drained using a needle and a syringe directly or under image guidance.
- Wound infection
- Stiffness in the arm or shoulder – this may develop secondary to the scarring in the wound. Usually physiotherapy and skin moisturizers can help in most of the time.
- Numbness of the arm, shoulder, armpit and parts of the chest can occur because the nerve that supplies sensation to the skin may need to be cut to remove the lymph nodes
- Lymph oedema: swelling of the arm. This may occur because lymphatic vessels have been disrupted. It can develop months or years after surgery