Comparison of the 5-year outcome and morbidity of three-dimensional conformal radiotherapy versus transperineal permanent iodine-125 implantation forearly-stage prostatic cancer

Purpose: To compare the prostate-specific antigen (PSA) relapse-free surviv al outcome and incidence of late toxicity for patients with early-stage pro state cancer treated at a single institution with either three-dimensional conformal radiotherapy (3D-CRT) or transperineal permanent implantation (TP I) with iodine-125 seeds. Materials and Methods: patients with favorable-risk prostate cancer, define d as a pretreatment PSA of less than or equal to 10.0 ng/mL, Gleason score of 6 or lower, and stage less than or equal to T2b, were selected for this analysis. Between 1989 and 1996, 137 such patients were treated with 3D-CRT and 145 with TPI. The median ages of the 3D-CRT and TPI groups were 68 yea rs and 64 years, respectively. The median dose of 3D-CRT war 70.2 Gy, and t he median implant dose was 150 Gy. Prostate-specific antigen relapse was de fined according to the American Society of Therapeutic Radiation Oncology C onsensus Statement, and toxicity was graded according to the Radiation Ther apy Oncology Group morbidity scoring scale. The median follow-up timer for the 3D-CRT and TPI groups were 36 and 24 months, respectively. Results: Eleven patients (8%) in the 3D-CRT group and 12 patients (8%) in t he TPI group developed a biochemical relapse. The 5-year PSA relapse-free s urvival rater for the 3D-CRT and the TPI groups were 88% and 82%, respectiv ely (P =.09). Protracted grade 2 urinary symptoms were more prevalent among patients created with TPI compared with 3D-CRT. Grade 2 urinary toxicity, which was manifest after the implant and persisted for more than 1 year aft er this procedure, was observed in 45 patients (31%) in the TPI group. In t hese 45 patients, the median duration of grade 2 urinary symptoms was 23 mo nths (range, 12 to 70 months). On the other hand, acute grade 2 urinary sym ptoms resolved within 4 to 6 weeks after completion of 3D-CRT, and the 5-ye ar actuarial likelihood of lace grade 2 urinary toxicity for the 3D-CRT gro up was only 8%. The 5-year actuarial likelihood of developing a urethral st ructure (grade 3 urinary toxicity) for the 3D-CRT and TPI groups was 2% and 12%, respectively (P <.0002). Of 45 patients who developed grade 2 or high er urinary toxicity after TPI, the likelihood of resolution or significant improvement of these symptoms at 36 months from onset was 59%. The 5-year l ikelihood of grade 2 late rectal toxicity for the 3D-CRT and TPI patients w as similar (6% and 11%, respectively; P =.97). No patient in either group d eveloped grade 3 or higher late rectal toxicity. The 5-year likelihood of p osttreatment erectile dysfunction among patients who were initially potent before therapy was 43% for the 3D-CRT group and 53% for the TPI group (P =. 52). Conclusion: Both 3D-CRT and TPI are associated with an excellent PSA outcom e for patients with early-stage prostate cancer. Urinary toxicities are mor e prevalent for the TPI group and subsequently resolve or improve in most p atients. In addition to evaluating long-term follow-up, future comparisons will require detailed quality-of-life assessments to further determine the impact of these toxicities on the overall well-being and quality of life of the individual patient. (C) 1999 by American Society of Clinical Oncology.