Background: The aim of this multicenter, double-blind, prospective study was to evaluate the potential utility of circulating tumor cell (CTC) measurements in predicting responses to anticancer therapies, including response to human epidermal growth factor receptor-2 (HER-2)-targeted agents, progression-free survival (PFS), and overall survival (OS) in Chinese women with metastatic breast cancer (MBC).
Patients and methods: Three hundred MBC patients planned to complete three CTC blood draws and two imaging studies.
Results: A total of 294 of the 300 MBC patients enrolled from six leading Chinese cancer centers were assessable. In multivariate Cox regression analyses, the baseline CTC number remained an independent prognostic factor for PFS [hazard ratio (HR) = 1.93; 95% confidence interval (CI) = 1.39-2.69; P < 0.001) and OS (HR = 3.76; 95% CI = 2.35-6.01; P < 0.001). Similar results were observed for CTC counts at the first follow-up visit for both PFS (P = 0.049) and OS (P < 0.001).
Conclusions: Enumeration of CTCs in Chinese MBC patients provides substantial prognostic information and is an independent factor associated with PFS and OS. Moreover, we demonstrated the prognostic value in the various disease subtypes, including HER-2-positive disease irrespective of therapy.
Keywords: circulating tumor cells; metastatic breast cancer; overall survival; progression-free survival.