Significance of circulating tumor cells in metastatic triple-negative breast cancer patients within a randomized, phase II trial: TBCRC 019

Academic Article

Abstract

  • Purpose: Circulating tumor cells (CTC) are prognostic in metastatic breast cancer (MBC). We tested whether EpCAM-based capture system (CellSearch) is effective in patients with triplenegative (TN) MBC, and whether CTC apoptosis and clustering enhances the prognostic role of CTC. Experimental Design: CTC enumeration and apoptosis were determined using the CXC CellSearch kit at baseline and days 15 and 29 in blood drawn from TN MBC patients who participated in a prospective randomized phase II trial of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) with or without tigatuzumab. Association between levels of CTC and patient outcomes was assessed using logistic regression, Kaplan-Meier curves, and Cox proportional hazards modeling. Results: Nineteen of 52 (36.5%),14 of 52 (26.9%), and 13 of 49 (26.5%) patients who were evaluable had elevated CTC (≥5 CTC/7.5 mL whole blood) at baseline and at days 15 and 29, respectively. Patients with elevated versus not elevated CTC at each time point had worse progression-free survival (PFS; P = 0.005, 0.0003, 0.0002, respectively). The odds of clinical benefit response for those who had elevated versus low CTC at baseline and days 15 and 29 were 0.25 (95% CI: 0.08-0.84; P = 0.024), 0.19 (95% CI: 0.05-0.17; P = 0.014), and 0.06 (95% CI: 0.01-0.33; P = 0.001), respectively. There was no apparent prognostic effect comparing CTC apoptosis versus non-apoptosis. Presence of CTC cluster at day 15 and day 29 was associated with shorter PFS. Conclusions: CTC were detected using CellSearch assay in approximately one-third of TNMBC patients. Elevated CTC at baseline and days 15 and 29 were prognostic, and reductions in CTC levels reflected response.
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    Digital Object Identifier (doi)

    Author List

  • Paoletti C; Li Y; Muñiz MC; Kidwell KM; Aung K; Thomas DG; Brown ME; Abramson VG; Irvin WJ; Lin NU
  • Start Page

  • 2771
  • End Page

  • 2779
  • Volume

  • 21
  • Issue

  • 12