Detection of circulating prostate derived cells in patients with prostate adenocarcinoma is an independent risk factor for tumor recurrence

Purpose: To determine whether the presence of prostate-derived cells in the peripheral blood circulation is a marker of prostate cancer and to define the clinical impact of the test. Materials and Methods: We tested the peripheral blood of 99 patients with p rostate adenocarcinoma (PAC), 79 of them undergoing radical prostatectomy, and 92 controls (31 healthy volunteers, 50 patients with adenoma and 11 wit h prostatitis) using a highly controlled procedure including reverse-transc riptase polymerase chain reaction (RT-PCR) targeted to prostate-specific an tigen (PSA) mRNA. Patients were followed for 26 +/- 12 (range: 4 to 49) mon ths. Forty tumor tissues were analyzed by immunohistochemistry for expressi on of p53 and E-cadherin antigens. Results: Thirty three (33%) patients with PAC and 2 (2%) controls scored po sitive (p <0.0001) for the test. Detection of circulating prostatic cells w as associated with development of metastases (p <0.001), with relapse (p <0 .001) and with a serum PSA level at diagnosis higher than 15 ng./ml. (p = 0 .009). The rate of development of metastases according to time was signific antly higher in patients who scored positive for the test (p <0.04). In a m ultivariate analysis, only the RT-PCR test was an independent risk factor a ssociated with relapse (RR: 6.7). Finally, E-cadherin expression was signif icantly lower in the tumor tissues of positive patients as compared with th ose who scored negative for the test (p <0.01). Conclusions: This RT-PCR procedure, performed at diagnosis and with appropr iate controls, is a clinically useful assay in evaluating the risk of tumor recurrence after radical prostatectomy in patients with PAC.