Evaluation and significance of circulating epithelial cells in patients with hormone-refractory prostate cancer

Authors


Jorge A Garcia, Department of Solid Tumor Oncology, Cleveland Clinic Taussig Cancer Center, 9500 Euclid Avenue/R35, Cleveland, Ohio 44195, USA.
e-mail: Garciaj4@ccf.org

Abstract

The urological oncology section is relatively long this month, and this reflects the many high-quality manuscripts we receive. When you consider our relatively high rejection rate, you will understand just how many papers on this topic are submitted. The high quality of oncology papers is clear in this month’s section. You will also notice that all but one of them are on prostate cancer, and the reason for this is similar to that mentioned above, as this topic is, as might be expected, the most commonly submitted in this section. However, I am only too happy to reassure readers, and those primarily interested in other types of urological cancer, that the imbalance in this month’s section is not a permanent fixture.

OBJECTIVE

To determine the feasibility of using flow cytometry fluorescence-activated cell sorting (FACS) analysis for detecting circulating epithelial cells (CECs) in patients with hormone-refractory prostate cancer (HRPC), and to determine whether CECs can be used to predict survival in these patients.

PATIENTS AND METHODS

Several prognostic models that include routinely used clinical and laboratory variables for predicting survival in men with HRPC have been reported; the presence of CECs measured by reverse transcriptase-polymerase chain reaction for prostate-specific antigen (PSA) in patients with HRPC is an independent prognostic factor for survival. CECs detected by FACS analysis correlate with advanced stage and poor survival outcome. A retrospective study was conducted to assess the presence of CECs by FACS analysis in metastatic HRPC patients initiating systemic chemotherapy with a taxane-based regimen. The association between clinical variables previously described and the presence of CECs along with the effect of the magnitude of CECs on survival was calculated, in 41 patients with HRPC, all of whom had peripheral blood collected for FACS analysis.

RESULTS

Except for four patients, all those with metastatic HRPC had detectable CECs. Among these patients, the number of CECs/mL was correlated with age, serum PSA level and serum alkaline phosphatase (ALP). Higher serum levels of PSA and ALP predicted a poor survival outcome. Similarly, patients with ≤1.8 CECs/mL had a significantly longer survival than those with more CECs/mL (P = 0.02). With a median follow-up of 15.4 months, the median overall survival for all patients was 18.4 months.

CONCLUSIONS

The presence of more CECs in patients with metastatic HRPC was associated with a poorer survival outcome; levels of ≥1.8 CECs/mL were associated with a shorter survival in patients with metastatic HRPC.

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