The specific treatment plan for breast cancer metastasis to the lymph nodes between the chest muscles mainly includes the following aspects, namely, surgical scavenging, radiotherapy, chemotherapy and targeted therapy. 1. Surgical scavenging: when lymph node metastasis is found, the corresponding lymph nodes need to be scavenged during surgery and localized enlargement resection should be carried out. 2. Radiotherapy: local radiotherapy can be chosen for the surgical area and metastatic lymph nodes. 3. Chemotherapy: chemotherapy is mainly the regular application of chemotherapeutic drugs, and the commonly used drugs in clinic include cisplatin, doxorubicin, paclitaxel and so on. 4. Targeted therapy: for people with gene mutation, they can choose to apply targeted drugs for control, and commonly used drugs include trastuzumab. If breast cancer has metastasis in the lymph nodes between the chest muscles, it is necessary to hospitalize in time and carry out standard treatment under the guidance of clinicians to avoid delaying the condition.