Five-year biochemical outcome and toxicity with transperineal CT-planned permanent I-125 prostate implantation for patients with localized prostate cancer

Purpose: To report the 5-year prostate specific antigen (PSA) relapse-free survival outcome and incidence of long-term morbidity for patients with loc alized prostate cancer treated with CT-planned permanent I-125 prostate imp lantation using a transperineal technique (TPI). Methods and Materials: Between 1989-1996, 248 patients with clinically loca lized prostate cancer were treated with TPI. The median age was 65 years (r ange: 45-80 years). The clinical stage was T1c in 143 patients (58%), Stage T2a in 102 (41%), and T2b in 3 (1%). Thirty patients (12%) had Gleason sco res <6, 158 patients (64%) had Gleason scores of 6, and 60 (24%) had scores greater than or equal to 7. The median pretreatment PSA was 7 ng/mL (range : 1-58 ng/mL). The median prescribed implant dose was 150 Gy. Patients were characterized as having favorable risk disease if their pretreatment PSA l evel was less than or equal to 10.0 ng/mL and Gleason score less than or eq ual to 6; those with one and two adverse prognostic features (PSA > 10 ng/m L and Gleason score >6) were classified as having intermediate and unfavora ble risk disease, respectively. PSA relapse was defined according to the Am erican Society of Therapeutic Radiation Oncology Consensus Statement, and t oxicity was scored according to the Radiation Therapy Oncology Group morbid ity scoring scale. The median follow-up was 48 months (range: 12-126 months ). Results: Thirty-eight patients (15%) developed a PSA relapse, and the overa ll 5-year PSA relapse-free survival (PRFS) rate was 71%. The 5-year PRFS ra tes for favorable-risk (n = 146), intermediate-risk (n = 85), and unfavorab le-risk (n = 17) patients were 88%, 77%, and 38%, respectively (p < 0.0001) . The 5-year PRFS rates among patients treated with a 2-month course of neo adjuvant androgen deprivation (NAAD) prior to TPI compared to patients trea ted with TPI only were 100% and 77%, respectively (p = 0.03). Multivariate analysis identified pretreatment PSA > 10 ng/mL and Gleason score >6 as ind ependent predictors for biochemical relapse after TPI. The 5-year actuarial likelihood of late Grade 2 urinary toxicity was 41%. The 5-year likelihood of urethral stricture development was 10%, and the median time to strictur e development was 18 months. One patient (0.4%) in the early phase of this clinical experience developed a Grade 4 urethral complication. The actuaria l incidence of late Grade 2 rectal bleeding was 9%. One patient (0.4%) deve loped a Grade 4 rectal complication. Conclusions: Especially for favorable risk disease, the 5-year biochemical outcome with this approach was excellent and appears to be comparable to ot her therapeutic interventions. Grade 2 urinary symptoms were common in thes e patients but gradually resolved in most. Improved treatment planning appr oaches that further constrain the urethral dose without compromising the ta rget volume dose will likely decrease the incidence of Grade 2 and 3 urinar y symptoms after TPI. (C) 2000 Elsevier Science Inc.