Systematic biopsies: do they add prognostic information in men with clinically localized prostate cancer treated with radiation therapy alone?

Abstract

To determine whether systematic biopsy can help predict treatment outcome in men with clinically localized prostate cancer treated with external-beam radiation therapy alone. Two hundred twenty-four men with clinically localized prostate cancer underwent ultrasound-guided systematic biopsies before undergoing external-beam radiation therapy. Median follow-up was 25 (range, 4-80) months. Treatment failure after irradiation was defined as a prostate-specific antigen (PSA) level greater than 1.5 ng/mL and rising. Univariate analysis demonstrated that the percentage of biopsy specimens involved by cancer was predictive of relapse-free survival. Patients in whom more than 50% of biopsy specimens were positive had significantly lower relapse-free survival rates at 36 months than patients with 50% or fewer positive biopsy specimens. After stratifying patients according to pretreatment PSA level, however, the percentage of positive biopsy specimens was no longer prognostic. Multivariate analysis demonstrated that pretreatment PSA level was the only variable that enabled prediction of relapse-free survival. Systematic biopsy added little further prognostic information beyond that provided by pretreatment PSA level. A larger series with longer follow-up is necessary to verify these results.