Evaluation of pretherapeutic Ki67 as predictive marker for response to neoadjuvant chemotherapy in patients with primary breast cancer.

e12500Background: The proliferation marker Ki67 is an established prognostic and predictive marker in breast cancer. The association between Ki67 and treatment response in the neoadjuvant setting, however, is still unclear. We have therefore evaluated whether Ki67 can predict pathological complete response (pCR) in women with neoadjuvant chemotherapy (NAC). Methods: We included prospectively collected data of women with primary breast cancer who underwent NAC from 2005–2015 at the Medical University of Vienna, Department of Gynecology. Chemotherapy consisted of 4 cycles epirubicin (90 mg/m2, q3w), followed by 4 cycles docetaxel (100 mg/m2, q3w), which was co-administered with trastuzumab in HER2-positive tumors. Ki67, hormone receptor and HER2-status were examined by immunohistochemistry using core needle biopsy specimens obtained prior to NAC. NAC-related effects were evaluated in surgical specimen; pCR was defined as the absence of invasive cancer in breast and axillary nodes. Results: A total of 95 wom...