Palladium-103 brachytherapy for prostate carcinoma.

Abstract

A report of biochemical outcomes for patients treated with palladium-103 (Pd-103) brachytherapy over a fixed time interval. Two hundred thirty patients with clinical stage T1-T2 prostate cancer were treated with Pd-103 brachytherapy and followed with prostate-specific antigen (PSA) determinations. Kaplan-Meier estimates of biochemical failure on the basis of two consecutive elevations of PSA were utilized. Multivariate risk groups were constructed. Aggregate PSA response by time interval was assessed. The overall biochemical control rate achieved at 9 years was 83.5%. Failures were local 3.0%; distant 6.1%; PSA progression only 4.3%. Significant risk factors contributing to failure were serum PSA greater than 10 ng/ml and Gleason sum of 7 or greater. Five-year biochemical control for those exhibiting neither risk factor was 94%; one risk factor, 82%; both risk factors, 65%. When all 1354 PSA determinations obtained for this cohort were considered, the patients with a proportion of PSAs < or = 0.5 ng/ml continued to increase until at least 48 months post-therapy. These data conformed to a median PSA half-life of 96.2 days. Prostate brachytherapy with Pd-103 achieves a high rate of biochemical and clinical control in patients with clinically organ-confined disease. PSA response following brachytherapy with low-dose-rate isotopes is protracted.