Testing for Circulating Tumor Cells (CTC)

Updated: June 2013

Overview

The CellSearch Circulating Tumor Cell (CTC) test is a simple blood test that helps oncologists in assessing the prognosis of patients with metastatic breast, colorectal, or prostate cancer. The CellSearch test is the only FDA-approved test for CTC assessment. Each result of the CellSearch test performed at Mayo Clinic is verified by both a cytotechnologist and a pathologist to ensure quality. In addition, Mayo Clinic pathologists and scientists are always available for consultation.   

Useful For

• Tests
  • Circulating Tumor Cells (CTC) for Breast Cancer by CellSearch, Blood (89089)
    An aid in monitoring patients with metastatic breast cancer
  • Circulating Tumor Cells (CTC) for Colorectal Cancer by CellSearch, Blood (89162)
    An aid in the monitoring of patients with metastatic colon cancer
  • Circulating Tumor Cells (CTC) for Prostate Cancer by CellSearch, Blood (60142)
    An aid in the monitoring of patients with metastatic prostate cancer
• Hot Topic
  • Circulating Tumor Cells and the CellSearch Assay, Kevin Halling, MD, PhD, and Michael Campion, Divisions of Laboratory Genetics and Anatomic Pathology, Mayo Clinic
• Communiqué
  • The CellSearch Assay for Circulating Tumor Cells: An Advance in Cancer Prognosis and Treatment, Kevin Halling, MD, PhD, Michael Campion and Jesse Voss, Divisions of Laboratory Genetics and Anatomic Pathology, Mayo Clinic

Studies have demonstrated CTCs can play an important role as an adjunct to imaging. (1-3) These studies demonstrate that metastatic breast cancer patients with ≥5 CTCs and imaging findings that show a stable/partial response have a shorter overall survival than those patients with <5 CTCs and imaging findings that show a stable/partial response. This is an indication that rising CTC levels occur before imaging can detect a possible change in patient status.

Studies suggest that the CellSearch test is able to detect tumor recurrence in metastatic breast cancer patients before tumor recurrence is detected by imaging. (4) This may help oncologists switch to more effective therapies.

Test Results and Consultations

• Each result provides a strong, independent predictor of survival
• Each result performed at Mayo Clinic is verified by both a certified cytotechnologist and pathologist to ensure quality
• Each report prepared at Mayo Clinic includes patient results for all previous CTC tests to aid oncologists with monitoring
• Mayo Clinic pathologists and scientists are always available for consultation on matters of test selection, collection and processing procedures, results interpretation, new test development and methodologies

Clinical References

1. Cristofanilli M, Budd GT, Ellis MJ, et al: Circulating tumor cells, disease progression, and survival in metastatic breast cancer. N Engl J Med 2004;351:781-791
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):3212-3221
3. deBono JS, Scher HI, Montgomery RB, et al: Circulating tumor cells predict survival benefit from treatment in the metastatic castration-resistant prostate cancer. Clin Cancer Res 2008 October 1;14(19):6302-6309
4. Budd TG, Cristofanilli M, Ellis MJ, et al: Circulating Tumor Cells versus Imaging—Predicting Overall Survival in Metastatic Breast Cancer. Clin Cancer Res 2006 12:6403-6409