Short-term Prostate-Specific Antigen Velocity Measurement before Prostate Biopsy

Abstract

Purpose: We investigated whether a short-term follow-up prostate-specific antigen (PSA) measurement before prostate biopsy is useful in predicting the presence of prostate cancer. Materials and Methods: From January 2004 to May 2008, 670 patients underwent transrectal ultrasound-guided prostate biopsy. The initial PSA (PSA1) was measured at the first outpatient visit. The second PSA (PSA2) was measured the evening before prostate biopsy. Only the patients with a PSA1 between 2.5 and 20 ng/ml and an interval between PSA1 and PSA2 of between 7 and 90 days were included in this study. The short-term PSA velocity (PSAVm) was defined as {(PSA2?PSA1/interval (days)}x30. Prostate volume (PV), PSA1, PSA2, and PSAVm were compared between the patients with prostate cancer and those with benign histology. Results: Of the 362 patients who fulfilled the entry criteria, 365 prostate biopsies were performed. The PSAVm differed significantly between patients with prostate cancer and those with benign histology (p=0.021). In patients with a PSA1 of 10-20 ng/ml, age, PV, PSA1, PSA2, and PSAVm were significantly different between patients with prostate cancer and those with benign histology, whereas in patients with a PSA1 of 2.5-10 ng/ml, only PV was significantly different. In multivariate logistic regression analysis excluding PSA1 and PSA2, PSAVm was a significant predictor of prostate cancer overall and in patients with a PSA1 of 10-20 ng/ml, but not in patients with a PSA1 of 2.5-10 ng/ml. Conclusions: PSAVm was significantly different between the benign group and the prostate cancer group. But, this difference was mainly the result of a falsely elevated PSA, and PSAVm was not a significant predictor of prostate cancer when the PSA1 was 2.5-10 ng/ml.