[2006] [669] Long-term disease free survival following prostate brachytherapy

Nelson N Stone*, Richard G. Stock, New York, NY.

Introduction and Objective: To describe the long-term biochemical (PSA) freedom from failure (FFF) in a large cohort of men treated with prostate brachytherapy Methods: 1562 men with T1-T3 prostate cancer were treated with real-time prostate brachytherapy from 1990-2002. Median age was 67 years (range 41-88) and median PSA was 7.2 ng/ml (range 0.3-300). Stage was < T2a in 67.3%; Gleason score was 2-6 in 68.2%, 7 in 22.1% and 8-10 in 9.7%. 675 (43.2%) were low risk, 392 (25.1%) intermediate and 495 (31.7%) high risk. Patients were treated with I-125 (54.7%-1), Pd-103 (12.5%-2) or Pd-103 combined with EBRT (32.8%-3). 55.6% received short term hormonal therapy (HT). Post-implant radiation dose (RD) was grouped into low (<80% of prescription), normal (>80-100%) and high dose (>100%). Patients with three PSA rises above a nadir (ASTRO) was classified as a failure. Survival functions were computed with Kaplan Meier and Cox regression.
Results: Median follow-up was 5 years (range 2-15). The bFFF rate for the entire cohort was 84% at 12 years. PSA < 10, 10-20 and >20 (87%, 81%, 57%), Gleason 2-6, 7, and 8-10 (87%, 81%, 70%), stage < T2a, T2b, T2c-T3 (88%, 74%, 79%), risk group (88%, 90%, 73%), implant type 1, 2, 3 (86%, 75%, 87%) and radiation dose group (55%, 75%, 90%) were all significant (p<0.0001). On multivariate analysis, dose (p<0.0001), PSA (p<0.0001), Gleason score (p<0.0001) and implant type (p=0.033) remained significant predictors of bFFF. In low risk patients bFFF for low dose group was 69%, normal-75% and high-94% (p=0.0005). In intermediate risk patients both dose and HT were significant predictors of bFFF (p<0.0001). In high risk patients on multivariate analysis only dose was significant (low-53%, normal- 66%, high- 80%, p=0.002). Conclusions: Prostate brachytherapy results in high bFFF rates. Radiation dose of at least 100% of prescription need to be delivered in order to insure long-term success.

Discussed Poster: Prostate Cancer: Localized (I) (9:00 AM-12:00 PM)