Changes in circulating carcinoma cells in patients with metastatic prostate cancer correlate with disease status

Objectives. To investigate the diurnal variations in circulating tumor cell s (CTCs) in metastatic carcinoma of the prostate (CAP) and to determine whe ther the change in CTCs correlated with disease progression. Methods. Samples were prepared by immunomagnetic selection of cells from 7 mL of blood targeting the epithelial cell adhesion molecule and differentia l fluorescent labeling of the collected cells using a nucleic acid dye, ant ibodies directed against the common leukocyte (CD45), and cytokeratin antig ens. Events that stained with the nucleic acid dye and expressed cytokerati n but lacked CD45 were defined as CTCs by multiparameter flow cytometry. Results. Male controls (n = 22) exhibited 0.8 +/- 1.2 events per 7 mL blood compared with 5.9 +/- 4.7 in 10 samples from patients with localized CAP a nd 46.6 +/- 65.6 events in 10 samples from patients with metastatic CAP. Di urnal testing of 8 cases demonstrated stable levels of CTCs. Ten patients w ere serially analyzed during a 6-month period for serum prostate-specific a ntigen and CTCs. The correlation between the prostate-specific antigen leve l and CTC number was fair. Slow disease progression was found in 4 patients with low CTC numbers (3.0 +/- 3) but it was significantly higher than the control group (P <0.002). Rapid disease progression occurred in 6 patients who demonstrated high CTC numbers (68.5 +/- 71.9). Two patients received ch emotherapy that caused substantial fluctuations in the CTCs with less prono unced changes in the prostate-specific antigen level. Conclusions. We conclude that the level of CTCs can be quantified in the ci rculation of patients with metastatic CAP and that the change in CTCs corre lates with disease progression with no diurnal variations. UROLOGY 58: 386- 392, 2001. (C) 2001, Elsevier Science Inc.