Radiotherapy Research Today is a free monthly online journal that collates and summarizes the latest research about Radiotherapy, including details on cancer treatment, side effects. | ||||||||
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Multi-institutional analysis of long-term outcome for stages T1-T2 prostate cancer treated with permanent seed implantation.Zelefsky MJ, Kuban DA, Levy LB, Potters L, Beyer DC, Blasko JC, Moran BJ, Ciezki JP, Zietman AL, Pisansky TM, Elshaikh M, Horwitz EM Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. zelefskm@mskcc.org 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 > or =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 > or =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 < or =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. Published 22 January 2007 in Int J Radiat Oncol Biol Phys, 67(2): 327-33.
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