Poster session 6: Prostate cancer| Volume 8, ISSUE 8, P688, September 2009

C91 Prostate brachytherapy with permanent iodine (125I) seed implant (LDR) – intermediate biochemical results and complications

      Introduction and Objectives

      To analyze retrospectively the intermediate biochemical results and complications, after 147 cases of localized prostate cancer, treated with prostate brachytherapy using permanent 125I implantation (Low Dose Rate – LDR).

      Material and Methods

      Between October 2006 and May 2009, 147 patients, age 49–82 years old, were treated with permanent 125I implantation brachytherapy. This technique was applied as monotherapy (145 Gy) for 110 patients, who had favorable prognostic, according with ABS recommendations (stage T1b-T2a, Gleason score ≤6, PSA ≤10 ng/ml). For 37 patients with unfavorable prognostic (stage T2b-T2c, Gleason score 7–10, PSA > 10), brachytherapy iodine implantation followed by external beam radiation therapy (EBRT – 45 Gy), at 6 weeks postimplant, was performed, to avoid biochemical relapse. The prostate volume was smaller than 60 g (mean volume 40 g), IPSS < 8, Qmax > 12 ml/s and TURP was not performed within the past 6 months. In 35 cases we used short-term neoadjuvant hormonotherapy (1–3 months). In order to accomplish the implantation planning, we followed the ESTRO/EAU recommendations for the definition of target volumes of risk organs and dosimetric parameters. The mean values were: D90 (indicator of implant quality and of probability of biochemical control) – 189 Gy, V100 – 98%, V150 – 75.9% and V200 – 43.4%. We monitored PSA value every 3 months during the first year and every 6 months thereafter.


      The evolution of the PSA levels, as indicated by our intermediate data, was the following: PSA mean value at implantation – 8.6 ng/ml, decreased with 71% at 3 months, 88% at 6 months, 90% at 9 months and 94% at 1 year. The PSA values at 18 months decreased with only 85%, probably due to PSA bounce. We registered 8 young patients, age 49–62 years old, with PSA bounce, starting at 12 months postimplant. We also had two patients with two consecutive elevations of the PSA levels, who are closely monitored (biochemical relapse?). Regarding the complications, immediately postoperative 40 patients had irritative voiding symptoms (urinary morbidity grade I and II according to RTOG scale) and two of them presented transitory complete urinary retention (urinary morbidity grade III). Another 7 patients developed rectal toxicity grade I and 2 cases mild radiation rectitis (rectal toxicity grade III), at 9 months postimplant. Twelve patients presented brachytherapyinduced erectile dysfunction.


      Prostate brachytherapy using permanent 125I seed implantation is a viable alternative to radical prostatectomy or external beam radiation therapy, for the curative treatment of localized prostate cancer. It determined an acceptable grade of urinary morbidity, minimum rectal toxicity and high probability to preserve erectile function.