There are 3 levels of axillary lymph nodes: level I, which is the bottom level and below the lower edge of the pectoralis minor muscle, level II, lying underneath the pectoralis minor muscle, and level III above the pectoralis minor muscle. Axillary lymph node dissection usually removes nodes in levels I and II and, in women with invasive breast cancer, this procedure accompanies a mastectomy. This procedure may also be done at the same time as, or after, a lumpectomy through a separate incision.
After being anesthetized, the patient is positioned lying supine, with the arm abducted and placed on an armboard at 90 degrees to the chest wall. This procedure is advocated for all patients who complete neoadjuvant treatment to down-stage the breast tumor, except when sentinel node biopsy is negative and undertaken prior to the neoadjuvant treatment. Patients who preoperatively have no evidence of axillary disease should undergo a sentinel node biopsy and have axillary dissection carried out if the sentinel node is positive. Axillary dissection is not very painful but the patient may feel slight discomfort and soreness at the wound site, which is easily managed by taking mild painkillers.