Improved tumour control probability with MRI-based prostate brachytherapy treatment planning

Backgroun. Due to improved visibility on MRI, contouring of the prostate is improved compared to CT. The aim of this study was to quantify the benefits of using MRI for treatment planning as compared to CT-based planning for temporary implant prostate brachytherapy. Material and methods. CT and MRI image data of 13 patients were used to delineate the prostate and organs at risk (OARs) and to reconstruct the implanted catheters (typically 12). An experienced treatment planner created plans on the CT-based structure sets (CT-plan) and on the MRI-based structure sets (MRI-plan). Then, active dwell-positions and weights of the CT-plans were transferred to the MRI-based structure sets (CT-planMRI-contours) and resulting dosimetric parameters and tumour control probabilities (TCPs) were studied. Results. For the CT-planMRI-contours a statistically significant lower target coverage was detected: mean V100 was 95.1% as opposed to 98.3% for the original plans (p < 0.01). Planning on CT caused cold-spots that influence the TCP. MRI-based planning improved the TCPs by 6-10%, depending on the parameters of the radiobiological model used for TCP calculation. Basing the treatment plan on either CT- or MRI-delineations does not influence plan quality. Conclusion. Evaluation of CT-based treatment planning by transferring the plan to MRI reveals underdosage of the prostate, especially at the base side. Planning on MRI can prevent cold-spots in the tumour and improves the TCP. © 2013 Informa Healthcare

Minimal displacement of novel self-anchoring catheters suitable for temporary prostate implants

Catheters were developed that can be fixed in the prostate gland by self-expanding parts for use in PDR brachytherapy. Daily CT-scans were made to investigate the magnitude of catheter displacement. The mean absolute displacement during the 3 day treatment was 1.2 mm. The resulting minor alterations in dose-volume parameters were of no clinical importanc

TREATMENT RESULTS OF PDR BRACHYTHERAPY COMBINED WITH EXTERNAL BEAM RADIOTHERAPY IN 106 PATIENTS WITH INTERMEDIATE- TO HIGH-RISK PROSTATE CANCER

Purpose: To evaluate treatment outcome of pulsed dose-rate brachytherapy (PDR) combined with external-beam radiotherapy (EBRT) for the treatment of prostate cancer. Methods and Materials: Between 2002 and 2007, 106 patients were treated by EBRT combined with PDR and followed prospectively. Two, 38, and 66 patients were classified as low-, intermediate-, and high-risk disease respectively according to the National Comprehensive Cancer Network criteria. EBRT dose was 46 Gy in 2.0-Gy fractions. PDR dose was increased stepwise from 24.96 to 28.80 Gy. Biochemical disease free survival and overall survival were determined by the Kaplan-Meier method. Cumulative incidence of late gastrointestinal (GI) and genitourinary (GU) toxicity were scored, according to the Common Terminology Criteria for Adverse Events. Results: The 3- and 5-year biochemical nonevidence of disease (bNED) were 92.8% (95% confidence interval [CI], 87.1-98.5) and 89.5% (95% CI, 85.2-93.8), respectively. Overall survival at 3 and 5 years was 99% (95% CI, 96-100) and 96% (95% CI, 90-100), respectively. The 3- and 5-year Grade 2 GI toxicity was 5.3% (95% CI, 0-10.6) and 12.0% (95% CI, 1.4-22.6), respectively. No Grade 3 or higher GI toxicity was observed. The 3- and 5-year Grade 2 or higher GU toxicity was 18.7% (95% CI, 10.3-27.1) and 26.9% (95% CI, 15.1-38.7), respectively. Conclusion: Results on tumor control and late toxicity of EBRT combined with PDR are good and comparable to results obtained with EBRT combined with high-dose-rate brachytherapy for the treatment of prostate cancer. (C) 2011 Elsevier In

Local Resection and Brachytherapy for Primary Orbital Rhabdomyosarcoma: Outcome and Failure Pattern Analysis

Survival in patients with orbital rhabdomyosarcoma (RMS) is excellent. Therefore, new local treatment modalities, such as brachytherapy, have been developed to minimize adverse events. Since 1990, patients with orbital RMS and a residual tumor after induction chemotherapy were eligible for resection and brachytherapy. Otherwise patients received external beam radiotherapy. In this study, the authors describe the outcome for 20 patients with primary orbital RMS. The aim was to assess risk factors for treatment failure in this single center cohort. In this retrospective cohort study, the authors reviewed imaging studies, surgery reports, histology reports, and radiotherapy plans in a multidisciplinary setting. The authors included 20 consecutive patients with orbital RMS, treated between 1990 and 2007, (median age: 7.4 years, range: 0.7-16.1; median follow up: 11.5 years). After induction chemotherapy, 12 patients were treated with surgery and brachytherapy, 2 with external beam radiotherapy, and in 5 patients who achieved complete remission, local treatment was withheld. In 1 patient, brachytherapy was incorrectly withheld after delayed surgery. Seven patients relapsed (no local treatment, N = 2; surgery and brachytherapy, N = 2; external beam radiotherapy, N = 2; surgery only, N = 1). The authors found no patient, tumor, or treatment characteristics that predisposed for treatment failure. Ten-year-overall survival and event-free survival were 89% and 65%, respectively. Overall survival in this cohort of orbital RMS patients was good, including surgery and brachytherapy as treatment modality for orbital RMS resulted in an effective local treatment approach with fewer adverse events than external beam radiotherapy. The authors could not identify factors predisposing for treatment failur