The presence of circulating tumor cells (CTC) is an independent prognostic factor for progression-free survival and breast cancer related death (BRD) 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 BRD.

In a prospective single center study, CTC were enumerated with the CellSearch system in 30 ml of peripheral blood of 602 patients before undergoing surgery for breast cancer. 97 patients had a benign tumor, 101 did not meet the inclusion criteria of which 48 patients with DCIS, leaving 404 stage I-III patients. Patients were stratified into unfavorable (CTC [greater than or equal to]1) and favorable (CTC = 0) prognostic groups.

>1 CTC in 30 ml blood was detected in 15 (15%) benign tumors, in 9 DCIS (19%), in 28 (16%) stage I, 32 (18%) stage II and in 16 (31%) patients with stage III. In stage I-III patients 76 (19%) had >1 CTC 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). 25 patients died of breast cancer related causes and 11 (44%) had >1 CTC. BRD was 4,3% for favorable and 14,5% for unfavorable CTC (p = 0.001). In multivariate analysis >1 CTC was associated with distant disease free survival, but not for overall recurrence free survival. CTC, progesterone receptor and N-stage were independent predictors of BRD in multivariate analysis.

Presence of CTC in breast cancer patients before undergoing surgery with curative intend is associated with an increased risk for breast cancer related death.

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