Case Studies

CellSearch® Circulating Tumor Cell (CTC) Test

Metastatic Breast Cancer (MBC)

Key Benefit of Using the CellSearch™ CTC Test

  • Elevated Circulating Tumor Cell (CTC) count provided an early indicator that patient’s prognosis remained poor.
  • Reduction in CTC levels, along with stable imaging results provided confidence that the patient could be moved to a less toxic therapy.

Case Study

Patient Information

  • Age:
  • Diagnosis:
Metastatic Breast Cancer (MBC)
  • Line of Therapy:
  • Current Therapy:
  • Time with Metastasis:
10 months
  • ER/PR & HER2 Status:
ER positive/PR positive/HER2 negative
  • Sites of Metastasis:

Case Study Snapshot

  • Patient wanted to pursue aromatase inhibitor therapy despite a baseline count of 32 CTC/7.5 mL of blood, and other non-favorable clinical factors.
  • A CTC level of 74 after 6 weeks and correlated with progressive disease as determined by imaging.
  • Patient was convinced to move to a chemotherapeutic regime to which she responded.
  • Subsequent monitoring of this patient by imaging and CTC analysis showed no evidence of progression and the patient was eventually switched to a less toxic therapy.

Patient Longitudinal Graph

Case Study 4 Graph

Background on the Patient

Sara G. presented with a large T2 (4.5 cm), N2 grade 3 infiltrating ductal carcinoma with 6 of 24 positive axillary lymph nodes in May of 2002. At her 5-year visit in the spring of 2007, after 49 months of hormonal therapy, she presented with a single organ liver metastases. A CellSearch® CTC test was ordered to determine a baseline reading. Her count of 32 CTC/7.5 mL of blood was elevated above the clinical cutoff of 5.

Despite a recommendation of chemotherapy with Bevacizumab for this visceral crisis, the patient instead wished to pursue a strategy of radical estrogen lowering with an aromatase inhibitor and multiple complementary therapies with a combined goal of lowering total body estradiol. Sara and her oncologist agreed that they would conduct an early reassessment of this strategy by both imaging (MRI) and CTC. Both of these diagnostic tools showed progression 6 weeks later. The CTC were 74, which put her in a poor prognostic category and this finding was helpful in convincing Sara to accept other treatment.

With Sara, the CellSearch® was used at recurrence to determine her prognosis at baseline. Her elevated CTC levels coupled with diffuse liver metastases alerted her oncologist to her poor prognosis very early on in her treatment. Her oncologist was able to use this information to convince her to abandon an ineffective hormonal approach to treatment.

On a new treatment, Sara had an excellent response from the Bevacizumab/Vinorelbine therapy as reflected by MRI and by her decreasing CTC counts. Her CTC count eventually dropped to zero and this provided additional confidence to place her on Doxorubicin for a lower side effect profile.

How CTC were valuable in the treatment of this MBC Patient

Initially the elevated CTC count in this patient demonstrated she was in a high-risk state. Along with imaging, CellSearch® CTC supported a non-response to the initial change in hormonal therapy after 6 weeks. Her drop in CTC over the following months demonstrated an improved prognosis on this new line of therapy and provided confidence that she could move to a less toxic therapy.

For in vitro Diagnostic Use

The CellSearch™ Circulating Tumor Cell Kit is intended for the enumeration of circulating tumor cells (CTC) of epithelial origin (CD45-, EpCAM+, and cytokeratins 8, 18+, and/or 19+) in whole blood.

The presence of CTC in the peripheral blood, as detected by the CellSearch™ Circulating Tumor Cell Kit, is associated with decreased progression-free survival and decreased overall survival in patients treated for metastatic breast, colorectal or prostate cancer.

For further information on intended use, warnings, and limitations, please refer to the CellSearch™ CTC Test Instructions for Use, or visit

CellSearch™ results should be used in conjunction with all clinical information derived from diagnostic test (e.g., imaging or laboratory tests), physical examination and complete medical history, in accordance with appropriate management procedures.

This case study is for educational purposes only and does not constitute professional medical advice. The information provided in this case study should not be relied upon as the basis for making patient management decisions. This case study is not intended to show that any line of therapy is any more or less effective than any other or no therapy.