Cancer surgery involves not only the complete removing of the tumour, but also removal of the surrounding lymph nodes. This is because cancer can spread via the lymphatic system to these lymph nodes. In breast cancer surgery, this procedure is known as an axillary clearance, in which most of the lymph nodes in the armpit are removed. However, there is a risk of lymphedema or swelling of the arm which is permanent and potentially disabling. Other side effects include shoulder stiffness, numbness and pain.
Only 1 in 5 patients with early breast cancer will have lymph node involvement. Hence, it is clear that an axillary clearance is not necessary for the majority of patients.
王医生表示，近年来前哨淋巴结活检（sentinel lymph node biopsy）已成为检查淋巴结是否涉及的黄金标准。
Excerpt from article published on 26 Oct 2019, 新明日报.