Purpose: Up to 40% of surgically treated prostate cancers are bound to be understaged by using current diagnostic modalities. To improve on current staging methods for prostate cancer, we evaluated whether nested reverse transcriptase-polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) mRNA can improve preoperative staging of prostate cancer.
Materials and methods: From May 1996 through November 1997, 30 patients with prostate cancer (T1-T3) were evaluated for PSAmRNA in their peripheral blood by nested RT-PCR before radical retropubic prostatectomy.
Results: A highly sensitive RT-PCR assay employed detected one PSA-expressing cell (LNCaP) diluted into ten million mononuclear cells. All 15 controls, including 9 women, showed negative PSAmRNA in their peripheral blood, whereas 16 of 30 (53%) patients with prostate cancer showed positive PSAmRNA in their preoperative peripheral blood. Interestingly, 7 patients with positive PSAmRNA had pathologically organ-confined prostate cancer. No significant relationship was demonstrated between positive PSA-PCR results and clinico-pathological parameters such as clinical stage, pretherapeutic serum PSA, pathological stage, seminal vesicle invasion, lymph node metastasis, vascular invasion, or Gleason sum.
Conclusion: Our present study showed that the results of PCR-based PSAmRNA assay had no significant association with clinico-pathological parameters. However, the prognostic significance of detecting the circulating prostate-specific signals requires a longer follow-up, which is currently under study.