Objective: To determine the effect of high-grade prostate cancer (Gleason pattern 5) on the prognosis of patients treated with Pd-103 brachytherapy.
Methods: A total of 499 higher-risk patients [Gleason score 7 or higher or prostate-specific antigen (PSA) 10-20 ng/mL] treated on a prospective protocol with Pd-103 and supplemental external beam radiation were studied. All prostate biopsies were reviewed for Gleason grade by 2 pathologists (L.T. and J.V.). Along with assignment of a Gleason score based on established criteria, the presence of any pattern 5 cancer was separately noted and photographed for future review. Freedom from biochemical failure was defined as a serum PSA ≤ 0.5 ng/mL at last follow-up.
Results: The biochemical control rate at 3 years for all 499 patients was 86%, with 348 patients followed beyond that time. Patients without pattern 5 cancer had an 89% rate of biochemical control at 3 years, versus 72% in the 87 patients with pattern 5 cancer (P = 0.0001). In Cox multivariate regression analysis, which included Gleason score, highest Gleason pattern, and pretreatment PSA, the Gleason score was the single most important predictor of biochemical control (P < 0.0001).
Conclusion: The presence of pattern 5 disease is a risk factor for biochemical failure. But in sharp contrast to prior studies, Pd-103 brachytherapy-based radiation appears to provide such patients with a high likelihood of cancer eradication.