Prostate stem cell antigen mRNA in peripheral blood as a potential predictor of biochemical recurrence in high-risk prostate cancer.

Objective: To determine whether the presence of prostate stem cell antigen (PSCA) mRNA in peripheral blood can predict biochemical recurrence (BCR) after radical prostatectomy in patients with high-risk prostate cancer.

Methods: High-risk disease was defined based on the presence of any one of the following three risk factors: prostate-specific antigen (PSA) > or = 20 ng/ml, a biopsy Gleason score (GS) > or = 8, or clinical stage > or = T2c. Nested reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to detect PSCA mRNA-bearing cells in peripheral blood. The relationship between PSCA detection and BCR after surgery was evaluated.

Results: Of the 250 patients, 103 (36.8%) with high-risk disease were included in the analysis. PSCA-mRNA was detected in 17 (16.5%) of these patients. Patients with high GS (> or = 7) tended to be PSCA-mRNA positive status (P = 0.045). Over a median 23 months of follow-up (range 3-47 months), BCR developed in 27 patients (26.2%). Cox regression hazards model analysis revealed that a RT-PCR PSCA positivity (HR, 4.549; 95%CI, 1.685-12.279; P = 0.003) independently increased the risk of BCR.

Conclusions: The presence of PSCA mRNA in peripheral blood is a significant predictor of BCR after radical prostatectomy in high-risk prostate cancer.