Value Of Mitotic Index In Residual Tumors Following Neoadjuvant Therapy For Breast Cancer: Single Institution Experience.

548Background: Pathologic complete remission (pCR) after neoadjuvant therapy (NAC) for breast cancer may predict favorable long-term outcome. Since markers of cell proliferation are linked to prognosis in breast cancer, we examined the prognostic value of the mitotic index (MI) in residual tumors after NAC. Methods: An institutional review board-approved retrospective study of all patients who received NAC for breast cancer at MCW between July 2004 - July 2014 was performed. Results: Of the 169 patients who received NAC, 167 patients received chemotherapy and 2 patients received hormonal therapy. Of the 167 patients, 84 patients were premenopausal and 83 patients were postmenopausal. The median age was 50 years (range 25-86). Pathology showed invasive ductal carcinoma in 141 patients, invasive lobular carcinoma in 18 patients and other histology in 7 patients. Mean tumor size prior to therapy was 4.5 cm (range 1-13 cm). Tumor grade was 1, 2, and 3 in 16, 80, and 64 patients, respectively. Clinical lymph n...