Pretreatment prostate-specific antigen velocity is associated with freedom from biochemical recurrence of prostate cancer after low-dose-rate prostate brachytherapy alone

PURPOSE: This report examines the relationship between pretreatment prostate-specific antigen (PSA) velocity (PSAV) and freedom from biochemical recurrence (FFBR) in men with prostate cancer treated with low-dose-rate prostate brachytherapy (LDRPB). METHODS AND MATERIALS: This is a report of 51 men treated with LDRPB between 1997 and 1999. Inclusion criteria: two or more evaluable PSA values >3 months apart and <18 months before treatment. PSAV is calculated using a linear regression equation. All patients had biopsy confirmed, clinically localized prostate cancer. All men were treated with I-125 LDRPB. The prescription dose was 144 Gy. Biochemical failure is determined from PSA values over time using the ASTRO Consensus Definition. FFBR is estimated using Kaplan-Meier method. Pretreatment variables analyzed include percentage positive biopsy cores, D-90, risk group, and PSAV. All p values are two-sided. RESULTS: The median follow-up is 60 months. The median pretreatment PSA is 6.5. 75% of men were Stage T1c, and 88% had Gleason score >= 6; 10% developed evidence of biochemical recurrence at a median of 13 months (range. 6-36). The 6-year estimate of FFBR is 90% for the entire Cohort. On univariate analysis, pretreatment PSAV and risk group are associated with FFBR. The 6-year estimate of FFBR in patients with a PSAV <2 ng/mL/yr is 100% vs. 80% (95% confidence interval: 64-96%) when the pretreatment PSAV is >= 2 ng/mL/yr before LDRPB (p = 0.017). CONCLUSIONS: Pretreatment PSAV is a predictor of FFBR after LDRPB in this population of men with prostate cancer. Men with a pretreatment PSAV >= 2 ng/mL/yr may warrant more aggressive treatment. (C) 2008 Published by Elsevier Inc on behalf of American Brachytherapy Society.