Detecting circulating prostate cells in patients with clinically localizedprostate cancer: clinical implications for molecular staging

Objective To evaluate the clinical utility of using the reverse transcripta se-polymerase chain reaction (RT-PCR) to detect prostate-specific antigen ( PSA) mRNA in peripheral blood samples from patients with prostate cancer, a s a predictor of extraprostatic disease, and to assess any correlations wit h known predictive markers of this condition. Patients and methods Immediately before radical prostatectomy, peripheral b lood samples were taken from 25 men with clinically localized prostate canc er and analysed for PSA mRNA using RT-PCR (in 'hot-start' conditions and co nfirmed using ClaI restriction enzyme). The relationships between PSA mRNA positivity, pathological and clinical features were analysed; PSA mRNA posi tivity, PSA level and biopsy Gleason score were then compared as predictors of extraprostatic disease. Results There was no relationship between PSA mRNA positivity and pathologi cal stage (pT2 or pT3), and no association between PSA mRNA positivity and serum PSA level, PSA density, the findings on a digital rectal examination or transrectal ultrasonography, and perineural invasion in the prostatic bi opsy. However, there was a significant correlation between the Gleason scor e of the preoperative biopsy and PSA mRNA positivity. The best predictors o f extraprostatic disease were the biopsy Gleason score and the PSA level. Conclusion There was no significant advantage in using the RT-PCR assay of PSA mRNA before surgery to stage prostate cancer and to discriminate betwee n organ-confined and extraprostatic neoplasms.