The aim of this study was to determine the presence of hematogenous neoplastic cells in patients with prostate cancer. We used a reverse transcription (RT) "nested" polymerase chain reaction (PCR) of prostate-specific antigen (PSA) mRNA to detect the presence of circulating tumor cells in 52 patients who underwent radical prostatectomy with lymphadenectomy. Blood samples were obtained before and after the surgical manipulation. Seven (13.5%) preoperative samples presented evidence of circulating neoplastic cells. All postoperative specimens studied presented a negative result at analysis 24 h after surgical manipulation. Although we did not find a statistical correlation between the PSA-PCR results and clinical-histopathological parameters, the presence of circulating prostate cells was strongly correlated with an elevated Gleason score of primary tumor (P<0.01). Thus our data show the positive effect of surgical treatment in removing the metastases source. The sensitive RT-nested PCR assay may play a crucial role in the administration of adjuvant therapy of patients with prostate adenocarcinoma.