Circulating tumor cells (CTCs) have been approved for marketing by the US Food and Drug Administration as a useful prognostic tool for the management of patients with advanced prostate cancer. To date, however, the optimal clinical cut-off levels of CTCs has not been determined, and the predictive value of CTCs in the setting of low-burden advanced prostate cancer has not been evaluated.
Goodman et al. have reported data on CTC levels in 100 patients with castration-resistant prostate cancer (CRPC) and correlated these data with clinicopathologic characteristics and conventional biomarkers, such as PSA and lactate dehydrogenase (LDH) levels. All patients were followed for up to 26 months, and overall survival status was documented.
- 49/100 patients (49 percent) were alive at the end of the study.
- CTC counts correlated well with overall survival (P < 0.001) but were also tightly interrelated to other biomarkers.
- In this study a level of 4 CTCs/7.5 ml appears to offer an optimal cut-off value with respect to survival outcomes and risk for metastatic disease.
- LDH level and CTC counts were independently prognostically significant on multivariate analysis.
It is clear that baseline CTC values provide important prognostic information and have specific predictive value in assessment of risk for metastatic disease. However, we are still learning how to use the CTC test to it’s greatest capability in routine clinical practice. Patients and their doctors should be cautious about overinterpretation of the results of CTC tests at this time.
Filed under: Management | Tagged: CellSearch, circulator tumor cell, CTC, prognosis |
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