Sentinel Lymph Node Biopsy

Sentinel lymph node biopsy is performed to assess whether there is any spread of breast cancer into the axilla. The technique is usually performed in conjunction with lumpectomy or mastectomy. Prior to surgery, an injection of dye (a radioactive isotope) is performed in the X-Ray Department. The dye is injected around the tumour and/or under the nipple. This dye is taken up into the lymphatic system and allows mapping of the lymphatic drainage of the breast. This is usually into the lymph nodes under the armpit (axilla) but may occasionally be toward the midline, between the ribs. It may take up to three hours to map which lymph nodes drain from the tumour site. The skin is usually marked over the lymph nodes of interest. During the surgical procedure, blue dye is also injected around the tumour to map out the lymphatic drainage in a similar fashion. At operation, an incision is made over the lymph node, which would most often be in the axilla. A small transverse incision , approximately 3 to 5 cm long, would be made in the axilla. A Gamma Probe allows identification of the lymph nodes containing dye. These are removed, usually 1 to 4 in number, and are sent for pathological assessment. The skin is closed with dissolvable sutures, and a drain is not usually required. Patients having lumpectomy and sentinel node biopsy can usually be discharged from hospital the day after surgery. Sentinel node biopsy reduces the risk of complications seen with a full axillary clearance, such as numbness, lymphoedema, and shoulder movement restriction.

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