Occult tumor cell contamination in patients with stage II/III breast cancer receiving sequential high-dose chemotherapy

Prognostic Impact of Circulating Tumor Cells for Breast Cancer Patients Treated in the Neoadjuvant "Geparquattro" Trial

Purpose: This study aimed to evaluate the prognostic impact of circulating tumor cells (CTC) detected in patients with operable or locally advanced breast cancer before and after neoadjuvant therapy (NT) within the clinical trial GeparQuattro.Experimental Design: Data on CTCs enumerated with the CellSearch system were available for 213 and 207 patients before and after NT, respectively. Associations of CTCs with disease-free survival (DFS) and overall survival (OS) were analyzed by nonparametric Kaplan-Meier estimates and parametric Cox regression.Results: After a median follow-up of 67.1 months, the detection of ≥1 CTC/7.5 mL and ≥2 CTCs/7.5 mL before NT was associated with reduced DFS (P = 0.031 and P < 0.0001, respectively) and OS (P = 0.0057 and P < 0.0001, respectively), whereas CTCs detected after NT did not correlate with DFS or OS. In parametric univariate and multivariate Cox models, ≥1 CTC/7.5 mL, ≥2 CTCs/7.5 mL, and absolute CTC numbers before NT revealed to be independent prognostic parameters of DFS and OS. CTC-negative patients with pathologic complete response (pCR) exhibited the best prognosis, whereas those with CTCs and less tumor response were at high risk of tumor relapse. In HER2 (ERBB2)-positive and triple-negative patients, ≥2 CTCs/7.5 mL detected before NT also were significantly associated with worse DFS and OS.Conclusions: Detection of CTCs before NT is an independent prognostic factor of impaired clinical outcome, and combined with pCR, it could be helpful to stratify breast cancer patients for therapeutic interventions. Clin Cancer Res; 23(18); 5384-93. ©2017 AACR.

Circulating tumor cells in early breast cancer: A connection with vascular invasion

Although circulating tumor cells (CTCs) have been studied in early breast cancer (EBC), their value in this setting is still not fully understood. We isolated and studied CTCs in the peripheral blood (PB) of 48 EBC patients pre-surgery and one and 6 months post-surgery using an approach involving EpCAM-independent enrichment and a dielectrophoresis-based device. Method feasibility and the correlation between CTCs and primary tumor features were evaluated. CTCs were found in 27.1% of pre-surgery patients, 20.9% of patients one-month post-surgery, and about 33% of patients 6-months post-surgery. CTCs were recovered singly for further molecular characterization. Pre-surgery CTC-positive patients more frequently had negative prognostic features, i.e. high proliferation, large tumor dimension, lymph node positivity and negative receptor status than the other subgroup. In particular, vascular invasion showed a statistically significant correlation with CTC-positivity. Our procedure proved feasible and capable of recovering CTCs from EBC patients. Furthermore, our results suggest that CTCs may be linked to vascular invasion and to other known negative prognostic factors.

Circulating tumor cells predict survival in early average-to-high risk breast cancer patients

Background

Circulating tumor cells (CTCs) have been shown to predict reduced survival outcomes in metastatic breast cancer.

Methods

CTCs were analyzed in 2026 patients with early breast cancer before adjuvant chemotherapy and in 1492 patients after chemotherapy using the CellSearch System. After immuno-magnetic enrichment for cells expressing the epithelial-cell adhesion molecule, CTCs were defined as nucleated cells expressing cytokeratin and lacking CD45. The patients were followed for a median of 35 months (range = 0–54). Kaplan–Meier analyses and the log-rank test were used for survival analyses. All statistical tests were two-sided.

Results

Before chemotherapy, CTCs were detected in 21.5% of patients (n = 435 of 2026), with 19.6% (n = 136 of 692) of node-negative and 22.4% (n = 299 of 1334) of node-positive patients showing CTCs (P < .001). No association was found with tumor size, grading, or hormone receptor status. After chemotherapy, 22.1% of patients (n = 330 of 1493) were CTC positive. The presence of CTCs was associated with poor disease-free survival (DFS; P < .0001), distant DFS (P < .001), breast cancer-specific survival (P = .008), and overall survival (OS; P = .0002). CTCs were confirmed as independent prognostic markers in multivariable analysis for DFS (hazard ratio [HR] = 2.11; 95% confidence interval [CI] = 1.49 to 2.99; P < .0001) and OS (HR = 2.18; 95% CI = 1.32 to 3.59; P = .002). The prognosis was worst in patients with at least five CTCs per 30mL blood (DFS: HR = 4.51, 95% CI = 2.59 to 7.86; OS: HR = 3.60, 95% CI = 1.56 to 8.45). The presence of persisting CTCs after chemotherapy showed a negative influence on DFS (HR = 1.12; 95% CI = 1.02 to 1.25; P = .02) and on OS (HR = 1.16; 95% CI = 0.99 to 1.37; P = .06)

Conclusions

These results suggest the independent prognostic relevance of CTCs both before and after adjuvant chemotherapy in a large prospective trial of patients with primary breast cancer.

The incidence of tumor cell contamination of peripheral blood stem cells: a meta-analysis to evaluate the impact of mobilization regimens and the influence on outcomes in breast cancer patients

Tumor cell contamination (TCC) of peripheral blood stem cells (PBSCs) is a major risk in the autologous PBSC transplant setting. However, the effect of different mobilization regimens (cytokines only versus cytokines + chemotherapy) on TCC of PBSCs and its impact on treatment outcomes have not been systematically reviewed. In the present meta-analysis, we aimed to investigate this effect in breast cancer patients since multiple studies have been conducted in this setting. We systematically searched MEDLINE and Cochrane Library up to May 2012. Seventeen studies (1,819 patients) were assessed. There was no significant difference in the incidence of TCC of PBSCs between the two mobilization regimens. When the analysis was restricted to granulocyte colony-stimulating factor as a cytokine, this difference was again not significant. We also found that TCC of PBSCs was associated with a higher annual recurrence rate in these patients. This suggests that there may be a significant risk for reinfusion of tumor cell-positive PBSCs, and whether it can increase the risk of disease recurrence needs to be determined. This study also raises important questions regarding the causes of TCC of PBSCs. These issues should be investigated systematically in PBSC transplant patients.

Tumor Cell Purging by Ex Vivo Expansion of Hemopoietic Stem Cells from Breast Cancer Patients Combined with Targeting ErbB Receptors

Tumor cell contamination might induce relapse after autologous transplantation in breast cancer patients. We used an ex vivo purging strategy to decrease the number of contaminating breast tumor cells in leukaphereses without altering the engraftment potential of the hemopoietic progenitor cells. This method is based on immunoselection of CD34+ cells derived from mobilized peripheral blood of patients with metastatic breast cancer and expansion in the presence of flt3 ligand, stem cell factor, interleukin 6, and thrombopoietin. Tumor contamination before and after culture was monitored by mammaglobin messenger RNA amplification by quantitative polymerase chain reaction. We analyzed both adherent and suspended cells obtained after 2 weeks of culture. Hemopoietic progenitors were increased among suspended cells. In this fraction, tumor cell contamination was decreased, whereas it increased within the adherent cell fraction. Experimental models using CD34+ cells from healthy donors spiked with breast cancer cells were also constructed to investigate whether treatment with anti-ErbB-receptor drugs could further reduce the tumor load without affecting the clonogenic potential of hemopoietic cells. For this purpose, we successfully assayed trastuzumab, a monoclonal antibody against ErbB-2, and gefitinib, an epidermal growth factor receptor tyrosine kinase receptor inhibitor. These results suggest that positively selected CD34+ cells from cancer patients contain tumor cells and that ex vivo expansion can reduce the tumor load of the suspended fraction. Target-based agents against ErbB-2, epidermal growth factor receptor, or both--such as trastuzumab or gefitinib--might increase the efficiency of purging.

Prognostic significance of occult tumor cells in the apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy and autologous hematopoietic progenitor cell support

We prospectively evaluated the prognostic significance of occult tumor cells (OTCs) contaminating the peripheral blood progenitor cell apheresis products of patients with advanced breast cancer receiving high-dose chemotherapy. Immunocytochemistry of peripheral blood progenitor cells was performed in 242 patients with high-risk primary breast cancer (HRPBC) and in 111 patients with metastatic breast cancer (MBC). OTCs were detected in 6.6% of HRPBC patients and in 16.2% of MBC patients (P = .005). In HRPBC, OTCs correlated with worse prognostic scores and larger tumor sizes, but not with axillary nodal status, hormone receptors, or HER2. In the MBC group, OTCs correlated with bone marrow involvement and with disease status at transplantation. The number of apheresis procedures was not associated with the risk of contamination. In HRPBC patients, at a median follow-up of 7 years (range, 1.5-11 years), the presence of OTCs correlated with worse event-free survival (P = .007) and overall survival (P = .002). In the MBC group, OTCs correlated with worse event-free survival (P = .04), but not overall survival (P = .2). In multivariate analyses, the presence of OTCs had an independent adverse effect on outcome in HRPBC, but not MBC. Our observations imply a direct role of OTCs in posttransplantation relapse in HRPBC.