P4-07-01: Circulating Tumor Cells, Disease Recurrence and Survival in Newly Diagnosed Breast Cancer.

Abstract

Abstract Background: The presence of circulating tumor cells (CTC) is an independent prognostic factor for progression-free survival and overall survival (OS) for patients with metastatic breast cancer beginning a new line of systemic therapy. The current study was undertaken to explore whether the presence of CTC at the time of diagnosis was associated with recurrence free survival (RFS) and breast cancer related death. Materials and Methods: In a prospective single center study, CTC were enumerated with the CellSearch system in 4 aliquots of 7.5 ml of peripheral blood of 504 patients before undergoing surgery for breast cancer between September 2003 and January 2009. Four hundred four had stage I-III disease and were followed for 6–90 months (median 48). One hundred had a benign tumor and served as a control group. Results: In the control group 15 (15%) had ≥1 CTC / 30 mL of blood. In stage I-III patients 76 (19%) had ≥1 CTC in 30 mL of blood of whom 16 (21.1%) developed a recurrence. In 328 patients with 0 CTC 38 (11.6%) developed a recurrence. Four year RFS was 88.4% for favorable CTC and 78.9% for unfavorable CTC (p =0.038). Breast cancer related death was 4,3% (14 of 328 patients) for favorable and 14,5% (11 of 76 patients) for unfavorable CTC (p = 0.001). CTC, PR receptor and stage were independent predictors of breast cancer related death in multivariate analysis. The corrected odds ratio after multivariate analysis for breast cancer related death in patiënts with CTC versus patiënts without CTC was 3,47. Discussion: Presence of CTC in breast cancer patients before undergoing surgery with curative intent is associated with an increased risk for recurrence and breast cancer related death. This supports the notion that the presence of CTC is also important in the primary disease setting. In this study the sensitivity of the CellSearch assay was increased by a fourfold increase in blood volume and a threshold for unfavorable of ≥1 CTC in 30 mL of blood, which lead to a relatively high background in the control group. Thus an increase in specificity is desired before initiation of prospective multicenter trials as well as a more practical way to process larger blood volumes. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-07-01.