Evaluation of circulating tumor cells
(CTCs) allows assessment of
patient prognosis and is predictive
of progression-free survival and
overall survival
The first and only clinically validated,
FDA-cleared test for capturing and
enumerating circulating tumor cells
(CTCs) to help inform clinical decision
making
Pivotal Clinical Trial—circulating tumor cells (CTCs) predict disease progression and survival in patients with mPC*1,2
Study design
Two hundred thirty-one patients with histologically confirmed mPC who were starting a new line of therapy were monitored with CTCs and prostate-specific antigen (PSA) levels at baseline and monthly thereafter.1
*Metastatic prostate cancer patients were defined as having two consecutive increases in the serum marker prostate-specific antigen above a reference level, despite standard hormonal management. These patients are commonly described as having androgen-independent, hormone-resistant, or castration-resistant prostate cancer. For more information on the intended use and limitations for the CELLSEARCH® Circulating Tumor Cell Test, please refer to the Instructions for Use which can be found at documents.cellsearchctc.com.
Case Study
68-year-old patient with hormone-resistant mPC refractory to previous chemotherapies
Nicholas Vogelzang, MD, Nevada Cancer Institute, Las Vegas, NV
68-year-old male was originally diagnosed with nodal metastasis in 1996; patient responded to hormone therapy and vaccines until August 2006, when worsening liver, nodal, and bone metastases were noted
Docetaxel was initiated; by February 2007, the patient experienced progression and developed docetaxel-related neurological toxicity
At this time, circulating tumor cells (CTCs) were 61†, lactate dehydrogenase (LDH) was 365 IU/L, and prostate-specific antigen (PSA) level was 10 ng/mL
Patient was treated with an investigational agent without effect; by April 2007, all tumor markers showed a sharp increase (CTCs=194, LDH=571 IU/L, PSA=23 ng/mL); markers continued to rise following treatment with another investigational drug
Radiation plus oral cytoxan therapy controlled the disease until November 2007, after which, tests showed an enlarged liver and malignant supraclavicular adenopathy
At this point, CTCs rose to 621, PSA level rose to 130 ng/mL, and LDH rose to 2602 IU/L; weekly paclitaxel was initiated
Within a month, CTCs declined to 8, LDH levels dropped to 574 IU/L, and supraclavicular nodes decreased in size; PSA level remained unchanged at 133 ng/mL
Carboplatin was added to therapeutic regimen, after which CTCs declined to 4 (below cutoff), LDH dropped to 306 IU/L, and PSA level decreased to 64 ng/mL
How CTCs helped inform the management of this patient
Circulating tumor cells were monitored regularly after this patient’s cancer became resistant to docetaxel and complemented clinical findings and therapeutic results over the course of 1 year of treatment.
This case demonstrates an instance when, in January 2008, 4 weeks after initiation of paclitaxel, both CTCs and LDH declined, whereas PSA remained unchanged. Previous studies comparing serial monitoring with CTC testing and PSA have shown that highly significant differences in overall survival between patients with unfavorable CTCs and favorable CTCs can be observed at all time points, whereas PSA evaluations were not significant until 6-8 weeks after the initiation of therapy.1,2 Furthermore, studies have shown that, in cases where CTC and PSA changes were discordant, CTC testing provided the most accurate assessment of prognosis.1,2
CELLSEARCH® CTC Test results should be used in conjunction with all clinical information derived from diagnostic tests (eg, 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. Please see instructions for use for indications and limitations of the CELLSEARCH® CTC Test as a monitoring aid in management of metastatic breast, colorectal, and prostate cancer.
†The clinical cutoff for CTCs per 7.5 mL of blood for mPC is ≥5.
References:
de Bono, JS, et al. Circulating Tumor Cells Predict Survival Benefit from Treatment in Metastatic Castration-Resistant Prostate Cancer. Clin Cancer Res 2008;14:6302-6309.
CELLSEARCH® Circulating Tumor Cell Kit (Epithelial) Instructions for Use. Menarini Silicon Biosystems Inc.
No
References
de Bono, JS, et al. Circulating Tumor Cells Predict Survival Benefit from Treatment in Metastatic Castration-Resistant Prostate Cancer. Clin Cancer Res 2008;14:6302-6309.
CELLSEARCH® Circulating Tumor Cell Kit (Epithelial) Instructions for Use. Menarini Silicon Biosystems Inc.
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