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

Abstract 

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 ¹²⁵I LDRPB. The prescription dose was 144Gy. 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, D₉₀, risk group, and PSAV. All p values are two-sided.

Results

The median followup 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 <2ng/mL/yr is 100% vs. 80% (95% confidence interval: 64–96%) when the pretreatment PSAV is ≥2ng/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 ≥2ng/mL/yr may warrant more aggressive treatment.

Keywords: Prostate cancer, Prostate brachytherapy, PSA velocity