ObjectiveTo analyze the value of internal mammary lymph node biopsy via intercostal space in staging and adjuvant therapy of breast cancer. MethodsThe clinical data of 305 breast cancer patients received any kind of radical mastectomy from may 2003 to January 2014 in the Jinan Military General Hospital of PLA were analyzed retrospectively. The patient age, axillary lymph node, and internal mammary lymph node status were integrated to investigate the changing of staging and postoperative adjuvant therapy of the breast cancer. ResultsThese 305 patients were divided into neoadjuvant chemotherapy group and non-neoadjuvant therapy group. There were 67 patients in the neoadjuvant chemotherapy group, including 45(67.2%) patients with axillary lymph node positive, 23(34.3%) patients with internal mammary lymph node positive. There were 23(34.3%) patients who had a change of pathology lympy node (pN) staging and 8(11.9%) patients who had a change of the pTNM staging. Meanwhile, there were 238 patients in the non-neoadjuvant chemotherapy group, including 155(65.1%) patients with axillary lymph node positive, 30(12.6%) patients with internal mammary node positive. There were 30(12.6%) patients who had a change of the pN staging and 23(9.66%) patients who had a change of the pTNM staging. There was a significant difference in the metastasis rate of the internal mammary lymph node (χ2=15.7, P < 0.05) or the changing ratio of the pTNM staging (χ2=5.3, P < 0.05) in two groups. ConclusionsInternal mammary lymph node status could affect pN staging of breast cancer, so do the pTNM staging (TNM, pathology tumor, lymph node, metastasis). The internal mammary lymph node status could guide the postoperative adjuvant radiative therapy by reducing excessive treatment of the internal mammary lymph node area, also could enhance the individual accurate therapy.