Multi-institutional analysis of long-term outcome for stages T1-T2 prostate cancer treated with permanent seed implantation
- Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
- Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)
- New York Prostate Institute, Oceanside, NY (United States)
- Arizona Oncology Services, Scottsdale, AZ (United States)
- Seattle Prostate Institute, Seattle, WA (United States)
- Chicago Prostate Cancer Center, Chicago, IL (United States)
- Department of Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH (United States)
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States)
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States)
- Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, MI (United States)
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)
Purpose: To assess long-term prostate-specific antigen (PSA) outcome after permanent prostate brachytherapy (BT) and identify predictors of improved disease-free survival. Methods and Materials: Eleven institutions combined data on 2,693 patients treated with permanent interstitial BT monotherapy for T1-T2 prostate cancer. Of these patients, 1,831 (68%) were treated with I-125 (median dose, 144 Gy) and 862 (32%) were treated with Pd-103 (median dose, 130 Gy). Criteria for inclusion were: available pre-BT PSA, BT {>=}5 years before data submission, BT between 1988-1998, and no androgen deprivation before failure. The median follow-up was 63 months. Results: Among patients where the I-125 dose to 90% of the prostate (D90) was {>=}130 Gy, the 8-year PSA relapse-free survival (PRFS) was 93% compared with 76% for those with lower D90 dose levels (p < 0.001). A multivariable analysis identified tumor stage (p = 0.002), Gleason score (p < 0.001), pretreatment PSA level (p < 0.001), treatment year (p = 0.001), and the isotope used (p = 0.004) as pretreatment and treatment variables associated with PRFS. When restricted to patients with available postimplantation dosimetric information, D90 emerged as a significant predictor of biochemical outcome (p = 0.01), and isotope was not significant. The 8-year PRFS was 92%, 86%, 79%, and 67%, respectively, for patients with PSA nadir values of 0-0.49, 0.5-0.99, 1.0-1.99, and >2.0 ng/mL (p < 0.001). Among patients free of biochemical relapse at 8 years, the median nadir level was 0.1 ng/mL, and 90% of these patients achieved a nadir PSA level <0.6 ng/mL. Conclusions: Outcome after permanent BT for prostatic cancer relates to tumor stage, Gleason score, pretreatment PSA, BT year, and post-BT dosimetric quality. PSA nadir {<=}0.5 ng/mL was particularly associated with durable long-term PSA disease-free survival. The only controllable factor to impact on long-term outcome was the D90 which is a reflection of implant quality.
- OSTI ID:
- 20944669
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 2 Vol. 67; ISSN IOBPD3; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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