Changes in Ki-67 in Residual Tumor and Outcome of Primary Inflammatory Breast Cancer Treated With Trimodality Therapy

Abstract

BackgroundLimited data are available on the prognostic role of Ki-67 changes in residual tumors after neoadjuvant chemotherapy in primary inflammatory breast cancer (IBC) patients treated with trimodality therapy. This study aims to evaluate changes in Ki-67 associated with disease-free survival (DFS) and overall survival (OS) in IBC patients without pathological complete response. Patients and MethodsWe identified a cohort of primary IBC patients with matched pre- and posttreatment samples treated with anthracycline and taxane-based regimen. All patients had a pathological evaluation, including ER, PR, HER2 status, and Ki-67 expression performed both at diagnostic core biopsy and at final surgery. Kaplan–Meier and Cox proportional hazards methods were used to assess DFS and OS rates and their relationship with clinicopathological features. ResultsTwo hundred and ten patients with stage III IBC were included. Sixty-three percent of residual tumors showed a decrease in Ki-67 positivity by at least 1%. The decrease of Ki-67 significantly correlated with better DFS (p = .001) and OS (P = .010) compared with no decrease, particularly in the luminal B-like and HER2-positive subgroups. The multivariate analysis showed that the decrease in Ki-67 level had a significant positive predictive value on DFS (HR = 0.47, 95% CI: 0.33-0.67; P< .001) and OS (HR = 0.59, 95% CI: 0.36-0.82; P= .004) in all IBC patients. ConclusionThe decrease of Ki-67 expression after neoadjuvant chemotherapy has a prognostic significance in IBC patients with residual disease. Evaluation of Ki-67 changes may help to identify subgroups of patients with worse outcome to receive novel treatment in this setting.