P1-026 - Circulating tumour cells and circulating stem-like cancer cells were prognostic factors in metastatic breast cancer

Abstract

Background: Circulating cancer stem-like cell (cCSC) has been revealed its property of chemoresistance; however, its predictive role in prognosis of patient with breast cancer remains unclear. Methods: Forty-eight patients with stage IV breast invasive ductal carcinoma were prospectively enrolled between April 2014 and January 2016. Circulating tumour cell (CTC) test was performed by negative selection strategy and Hoechst+CD45-EpCAM+ cells were identified as CTCs. The Hoechst+CD45-EpCAM+CD133+ cells were identified as circulating cancer stem-like cells (cCSC). CTC analysis was performed at the baseline, 4th week and 3rd month of first line palliative chemotherapy. Results: We found that the performance status and the baseline cCSC/CTC ratio were independent prognostic factors for progression-free survival (PFS) (P = 0.005 and P < 0.0001, respectively). Baseline CTCs and baseline cCSC/CTC ratio were independent prognostic factors for overall survival (OS) (both P < 0.0001). The change in cCSCs from baseline to 4th week and 3rd month was prognostic factor for PFS (P = 0.011 and P < 0.001, respectively) and the change in CTCs from baseline to 4th week and 3rd month were prognostic factor for PFS and OS (P value in PFS: P < 0.001; p value in OS: P = 0.012 and P = 0.020). At the 3rd month response evaluation after chemotherapy, the cCSC/CTC ratio in those patients with disease control (n = 36) seems to be insidiously increasing, which suggests a potential early sign of chemoresistance. Conclusion: The baseline CTCs and the baseline cCSC/CTC ratio were prognostic in survival among patients with metastatic breast cancer. In disease controlled group, the gradual increase of cCSC/CTC ratio probably suggests the upcoming failure of chemotherapy.