When breast cancer spreads to the armpit, indicating axillary lymph node metastasis, axillary lymph node dissection is required along with radical resection of the primary tumor. Postoperative adjuvant chemotherapy should be administered, with radiotherapy, targeted therapy, or immunotherapy considered as appropriate based on pathological type and metastasis status.

Breast cancer is highly prone to lymphatic metastasis, and the most common site for lymphatic metastasis is the axillary lymph nodes, also known as the sentinel lymph nodes of breast cancer. The presence of axillary lymph node metastasis can typically be confirmed preoperatively through methods such as ultrasound and sentinel lymph node biopsy.

If a biopsy indicates metastasis in the sentinel lymph nodes, axillary lymph node dissection should be performed in addition to radical mastectomy to thoroughly remove cancer cells. Moreover, positive sentinel lymph node biopsy is one of the indications for postoperative adjuvant chemotherapy.

If breast cancer with axillary lymph node metastasis is detected, prompt medical treatment is essential. Treatment options should be selected under the guidance of a professional physician to avoid delays that could worsen the condition.