Early (operable) breast cancer is defined as tumours not more than five centimetres in diameter,** with either impalpable or palpable, but not fixed, lymph nodes and with no evidence of distant metastases.1
Treatment of early breast cancer involves surgery to remove the tumour (a lumpectomy or mastectomy) and management of the axilla. The axilla is assessed to determine if the cancer has spread to surrounding lymph nodes (usually in the axilla) and to determine treatment options and prognosis. Traditionally, a lumpectomy or mastectomy with axillary lymph node dissection has been the surgical standard of care used to manage early breast cancer. Axillary lymph node dissection (either level I, II or III) involves surgically removing a significant number of the lymph nodes in the axilla. Axillary dissection has been associated with morbidity, particularly lymphoedema.1 Only about 30% of women with early breast cancer will have positive axillary nodes, therefore around two thirds of women receive no benefit from axillary dissection and are at risk of morbidity associated with the procedure.2
Sentinel node biopsy is a minimally invasive surgical technique used to assess the axilla that may offer less arm morbidity for the patient (for example, less risk of lymphoedema). Sentinel node biopsy is not a form of unguided axillary sampling. The sentinel node is the first lymph node to which cancer cells are likely to spread from the primary tumour in the breast. The sentinel node can be located by injecting a detection agent (for example, blue dye, radioactive isotopes) around the cancer and locating the lymph node(s) to which the detection agent has travelled. Once detected, the sentinel node(s) is surgically removed and investigated by a pathologist to determine if cancer cells are present. If cancer cells are found (a positive sentinel node), further surgery to remove more lymph nodes, and/or radiotherapy to the area may be required.