In order to evaluate the molecular biology of the tumor cell population, a CTC (Circulating tumor cells) is an important part of cancer testing that is often missed by conventional oncologists.
By far, the most important test is this one because tumor circulatory stem cells can shed from a 2mm tumor and these are the cells that are the engins of metastases, from which most cancer patients die.
The best test on the market is the CellSearch Circulating Tumor Cell (CTC) test. This test is a simple blood test. Some conventional ontologists use this test in assessing the prognosis of patients with metastatic breast, colorectal, or prostate cancer. But most integrative and holistic oncologists will use this test for many more cancers and indications.
The CellSearch System identifies and enumerates the number of circulating tumor cells (CTCs) in a blood specimen.(1) Studies suggest that the number of CTCs is associated with progression-free and overall survival in patients with metastatic colorectal cancer.(2,3)
Results are reported as favorable or unfavorable. In patients with metastatic colon cancer, the finding of > or =3 circulating tumor cells/7.5 mL of blood is predictive of shorter progression-free survival and overall survival.(2)
This test is FDA approved only for monitoring colon, prostate and breat cancer patients with metastatic disease. Blood specimens must be drawn into a CellSave tube and be processed in the laboratory within 96 hours of draw. (4)
This test does not provide information about the primary site of a tumor. It measures the risk of metastases. The CellSearch test is the only FDA-approved test for CTC assessment. Each result of the CellSearch test is verified by both a cytotechnologist and a pathologist to ensure quality.
Currently, Medicare and some private insurers cover the CellSearch test, which costs about $350
1. Allard WJ, Matera J, Miller MC, et al: Tumor cells circulate in the peripheral blood of all major carcinomas but not in healthy subjects or patients with nonmalignant diseases. Clin Cancer Res 2004 Oct;10:6897-6904
2. Cohen SJ, Punt CJ, Iannotti N, et al: Relationship of circulating tumor cells to tumor response, progression-free survival, and overall survival in patients with metastatic colorectal cancer. J Clin Oncol 2008 Jul;26(19):3213-3221
3. Cohen SJ, Punt CJ, Iannotti N, et al: Prognostic significance of circulating tumor cells in patients with metastatic colorectal cancer. Ann Oncol 2009;20(7):1223-1229
4 Patients on doxorubicin (Adriamvcin) must wait a minimum of 7 days after administration before blood can be drawn for this test.
For an understanding of circulatory Tumor and cancer stem cells, see this Source.