[Sheila]

Is this the test you are asking about by Quest Diagnostics?

CellSearchTM' Circulating Tumor Cells, Breast Cancer

Test Summary

Clinical Use
•Predict progression-free survival (PFS) and overall survival (OS) in patients with metastatic breast cancer
Clinical Background
Circulating tumor cells (CTCs) are extremely rare in healthy individuals and patients with nonmalignant diseases but are present in patients with various metastatic carcinomas with a wide range of frequencies.1-2 Some clinical studies indicate the assessment of CTCs can assist physicians in monitoring and predicting cancer progression and in evaluating response to therapy in patients with metastatic cancer.3-5
In patients with metastatic breast cancer, the number of CTCs has been shown to be a significant predictor of progression-free survival (PFS) and overall survival (OS).6,7 In a study by Cristofanilli et al,7 patients undergoing treatment for metastatic breast cancer with >5 CTCs/7.5 mL whole blood had shorter median PFS (2.7 months vs 7.0 months, P<0.001) and shorter OS (10.1 months vs >18 months, P<0.001) than patients having <5 CTCs/7.5 mL blood. In the same study, a decrease in the number of CTCs to <5 from baseline to first follow-up (4-5 weeks after initiation of new therapy) was also found to be predictive of PFS and OS. These results suggest the number of CTCs is a useful prognostic guide for patients with metastatic breast cancer and can reliably estimate disease progression and survival earlier (4-5 weeks vs 8-12 weeks, respectively) than traditional imaging methods.
Individuals Suitable for Testing
Patients with metastatic breast cancer, prior to a new course of therapy and at follow-up.
Specimen Requirements
•10 mL room temperature whole blood collected in CellSave Preservative Tube™'; 7.5 mL minimum.•Ship promptly; specimen must be tested within 72 hours of collection. Provide sample collection date and time. Do not refrigerate.•Samples may be collected prior to therapy and at first follow-up visit (4-5 weeks after initiation of new therapy). Allow at least 7 days after administration of doxorubicin before sample collection.
Method
•Immunomagnetic sample enrichment using antibodies targeting epithelial cell adhesion molecule (EpCAM) and cell labeling with fluorescent nucleic acid dye•Epithelial cells distinguished from leukocytes using fluorescent labeled monoclonal antibodies specific for leukocytes (CD-45) and epithelial cells (cytokeratins 8,18, and 19)•Results reported as number of CTCs/7.5 mL of whole blood•Analytical sensitivity: 1 CTC/7.5 mL whole blood•Analytical specificity: 99.7%2•Aliases: Breast Cancer CellSearch