International Brachytherapy Congress in Barcelona 2004
Iodine-125 prostate brachytherapy in localized prostate cancer: importance of team experience for dose delivery and toxicity.
Neubauer S1,2, Derakhshani P1,2, Metz J1,3, Spira G1,3
(1) West German Prostate Center, Cologne, Germany
(2) Department of Urology, Klinik am Ring, Cologne
(3) Department of Radiooncology, Klinik am Ring, Cologne
Background and purpose:
In transperineal permanent prostate brachytherapy with I-125 adequate radiation doses are required for good clinical results. Moreover permanent seed implantation is a highly operator-dependent procedure with a frequence-related learning curve. After 3 years of seedimplantation in a constant team of four physicians (two urologists and two radiooncologists) the purpose of the present report is to determine whether dosimetric quantifiers of implant adequacy, OR-time and postoperative toxicity were affected by the experience of the implantation team.
Materials and methods:
Between February 2001 and January 2004, 518 consecutive patients were treated with permanent seed implants using iodine RAPID-strands and intraoperative online planning technique (IOT). 461 low risk patients were treated by seedimplant alone and 57 intermediate and high-risk patients recevied an additional external beam therapy. Dosimetric quantifiers (DQ) of implant adequacy were calculated using a computed tomography (CT) scan performed 1 month following prostate brachytherapy. Urinary toxicity was measured with IPSS and QoL-scores. Patients were divided into group 1:implants number 1-259 and group 2: implants number 260-518. Groups were compared regarding preoperative and postoperative IPS-Scores and achieved dosimetric quantifiers pre- and postoperatively.
Patients in group 1 had a lower mean D90 to the prostate compared to men in group 2 (144.13 Gy vs. 152.26 Gy). Toxicity was very similar in both groups: mean IPPS in group 1 at 0/1/3/6/12 months after treatment being 6.7/14.6/13.6/10.5/7.5 compared to group 2 (7.3/15.4/14.3/10.7/8.3). Mean procedure duration including online-planning, needle-loading and implantation was reduced from 112 (57-183) minutes in group 1 to 66 (34-82) minutes in group 2. Urinary toxicity in combined treatment was not higher compared to seed implant alone.
There were no major differences in early and latter seed implants in terms of urinary toxicity. Quality of dose distribution was improved markedly with increased experience. Maybe because we used the intraoperative online planning technique (IOT) from the first case on and had no changes in the team constellation differences were smaller than expected and reported earlier.