Circulating tumor cells (CTC) can be identified in blood or bone amrrow of patients with many breast cancer. Between 10% and 30% of patients with stage I to III breast cancer and 50% to 70% of women with metastatic breast cancer have detectable CTCs. A number of studies suggest that presence and elevation of CTCs is associated with worse prognosis. In the metastatic setting, persistent CTC after 3 to 5 weeks of a new therapy seem to indicate lack of activity of that regimen, and an ongoing prospective randomized clinical trial is addressing the relative worth of changing to an alternative treatment rather than waiting for classic clinical and radiologic evidence of progression. Recent technical advances offer the promise of further genotyping and phenotyping for important tumor-associated genes and proteins. However, until trials are completed and reported, this remain an investigational treatment.
In 2007 ASCO recommended: "Present data are insufficient to recommend assessment of bone marrow micrometastases for management of patients with breast cancer. The measurement of circulating tumor cells (CTCs) should not be used to make the diagnosis of breast cancer or to influence any treatment decisions in patients with breast cancer. Similarly, the use of the recently U.S. Food and Drug Administration (FDA)-cleared test for CTC (CellSearch Assay) in patients with metastatic breast cancer cannot be recommended until further validation confirms the clinical value of this test.
Daniel F. Hayes and Jeffrey Smerage Is There a Role for Circulating Tumor Cells in the Management of Breast Cancer? Clinical Cancer Research June 2008 14; 3646
F.-C. Bidard , Y. M. Kirova , A. Vincent-Salomon , S. Alran , Y. de Rycke , B. Sigal-Zafrani , X. Sastre-Garau , L. Mignot , A. Fourquet , and J.-Y. Pierga Disseminated tumor cells and the risk of locoregional recurrence in nonmetastatic breast cancer Annals of Oncology Advance Access published on November 1, 2009, DOI 10.1093/annonc/mdp200. Ann Oncol 20: 1836-1841
Harris L, Fritsche H, Mennel R, Norton L, Ravdin P, Taube S, Somerfield MR, Hayes DF, Bast RC Jr, American Society of Clinical Oncology. American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer. J Clin Oncol 2007 Nov 20;25(33):5287-312.