Focal salvage iodine-125 brachytherapy for prostate cancer recurrences after primary radiotherapy: a retrospective study regarding toxicity, biochemical outcome and quality of life.

PURPOSE: Whole-gland salvage for recurrent prostate cancer (PCa) shows high failure and toxicity rates. Early and adequate localization of recurrences enables focal salvage, thereby potentially improving functional outcomes, while maintaining cancer control. MATERIALS AND METHODS: Retrospective analysis yielded 20 focal salvage I125 brachytherapy patients for locally recurrent PCa after primary radiotherapy. Tumor was defined by multiparametric MRI and correspondence with transrectal biopsies. Dose data were obtained intra-operatively. The tumor was prescribed ⩾144 Gy. Toxicity was scored by the Common Terminology Criteria for Adverse Events version 4 (CTCAE-4). Biochemical failure (BF) was defined using the Phoenix criteria (PSA-nadir + 2.0 ng/ml). Quality of life (QoL) was measured by SF-36 Health Survey and European Organization of Research and Treatment of Cancer (EORTC) C30+3 and PR25 questionnaires. RESULTS: With a median follow-up of 36 months (range 10-45), six patients experienced BF, of which three had no initial response. Grade 3 genitourinary (GU) toxicity occurred in one patient (a urethral stricture). The five previously potent patients retained erectile function. QoL remained decreased with regard to urinary symptoms. CONCLUSION: Focal salvage I125 brachytherapy showed one grade 3 GU toxicity in the 20 treated patients. Biochemical response and QoL were acceptable.

Influence of dose on risk of acute urinary retention after iodine-125 prostate brachytherapy.

PURPOSE: To assess the influence of dose on the risk of acute urinary retention (AUR) after iodine-125 prostate brachytherapy. METHODS AND MATERIALS: Between January 2005 and December 2008, 714 consecutive patients with localized prostate cancer were treated with iodine-125 prostate brachytherapy at our department. All patients completed four imaging studies: magnetic resonance imaging before and 4 weeks after treatment and intraoperative three-dimensional transrectal ultrasonography before and after implantation. The development of AUR was prospectively recorded. The evaluated treatment and dosimetric parameters included prostate volume, number of needles and seeds used, intra- and postoperative prostate edema, percentage of prostate volume receiving 100%, 150%, and 200% of the prescribed dose to the prostate, minimal dose received by 90% of the prostate volume, and percentage of the urethra receiving 100%, 150%, and 200% of the prescribed dose. Logistic regression analysis was used to examine which factors were associated with AUR. RESULTS: Of the 714 patients, 57 (8.0%) developed AUR. On univariate analysis, the following treatment and dosimetric factors were significantly associated with AUR: International Prostate Symptom Score (odds ratio [OR], 2.07, per 10-point increase), preimplant prostate volume (OR, 1.06), postimplant prostate volume (OR, 1.04), number of needles used (OR, 1.09), and number of seeds used (OR, 1.03). On multivariate analysis, the only independent predictive factors for AUR were pretreatment prostate volume (OR, 1.05) and International Prostate Symptom Score (OR, 1.76, per 10-point increase). Patients with a pretreatment prostate volume >35 cm(3) had a 10.4% risk of developing AUR compared with 5.4% for those with a prostate volume of ≤ 35 cm(3). No association was found between any of the dosimetric parameters and the development of AUR. CONCLUSION: The radiation dose, within the range studied, did not influence the risk of AUR after iodine-125 prostate brachytherapy. Prostate volume and International Prostate Symptom Score were the most important predictors of AUR.

Decline of dose coverage between intraoperative planning and post implant dosimetry for I-125 permanent prostate brachytherapy: comparison between loose and stranded seed implants.

BACKGROUND AND PURPOSE: In permanent prostate brachytherapy the dose distributions 4 weeks post implant differ from the intraoperative dose distributions. The purpose of this study is to compare intraoperative planning and post implant dosimetry for loose and stranded seed implants. MATERIALS AND METHODS: This study investigates prostate dose coverage in 389 patients with stage T1 or T2 prostate cancer treated in the years 2005, 2006 and 2007. The patients received either a loose seed or a stranded seed implant. All patients had US-based intraoperative planning and CT/MRI-based post implant dosimetry after 4 weeks. RESULTS: Intraoperative and post implant D(90) values amounted 183+/-13 Gy (mean+/-standard deviation) and 161+/-30 Gy, respectively. Decline of D(90) values (mean and 95% confidence interval) between intraoperative planning and post implant dosimetry for RAPID strand (n=67), Intersource strand (n=136) and loose selectSeeds (n=186) implants amounted to -40 (-45 to -34) Gy, -25 (-28 to -21) Gy and -15 (-18 to -21) Gy, respectively. CONCLUSIONS: The patients treated in the period 2005-2007 with stranded or loose seed implants had on average adequate D(90) values of 161+/-30 Gy. Post implant D(90) values were 22+/-27 Gy lower compared to intraoperative planning. Decline of dose coverage between intraoperative planning and post implant dosimetry was significantly larger for the stranded seed implants.