Predictors of urinary toxicity with MRI-assisted radiosurgery for low-dose-rate prostate brachytherapy.

Autor: Boyce-Fappiano D; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Bathala TK; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Ye R; Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX., Pasalic D; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Gjyshi O; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Pezzi TA; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Noticewala SS; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., McGinnis GJ; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Maroongroge S; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Kuban DA; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Nguyen QN; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., McGuire SE; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Hoffman KE; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Choi S; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Tang C; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Kudchadker RJ; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX., Frank SJ; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX. Electronic address: sjfrank@mdanderson.org.
Jazyk: angličtina
Zdroj: Brachytherapy [Brachytherapy] 2020 Sep - Oct; Vol. 19 (5), pp. 574-583. Date of Electronic Publication: 2020 Jul 15.
DOI: 10.1016/j.brachy.2020.06.011
Abstrakt: Purpose: MRI-assisted radiosurgery (MARS) is a modern technique for prostate brachytherapy that provides superior soft tissue contrast. The purpose of this analysis was to evaluate treatment planning factors associated with urinary toxicity, particularly damage to the membranous urethra (MUL) and external urethral sphincter (EUS), after MARS.
Material and Methods: We retrospectively reviewed 227 patients treated with MARS. Comparisons were made between several factors including preimplantation length of the MUL and EUS dosimetric characteristics after implantation with longitudinal changes in American Urological Association (AUA) urinary symptom score.
Results: Rates of grade 3 urinary incontinence and obstructive urinary symptoms were 4% and 2%. A piecewise mixed univariate model revealed that MUL and V 200 , V 150 , V 125 , and D 5 to the EUS were all associated with increased rates of urinary toxicity over time. On univariate logistic regression, MUL >14.2 mm (odds ratio [OR] 2.03 per cm 3 , 95% confidence interval [CI] 1.10-3.77, p = 0.025), V 125 to the EUS (OR 3.21 cm 3 , 95% CI 1.18-8.71, p = 0.022), and use of the I-125 isotope (OR 3.45, 95% CI 1.55-7.70, p = 0.001) were associated with subacute urinary toxicity (i.e., that occurring at 4-8 months). Optimal dose-constraint limits to the EUS were determined to be V 200  < 0.04 cm 3  (p = 0.002), V 150  < 0.12 cm 3  (p = 0.041), V 125  < 0.45 cm 3  (p = 0.033), D 30  < 160 Gy (p = 0.004), and D 5  < 218 Gy (p = 0.016).
Conclusions: MARS brachytherapy provides detailed anatomic information for treatment planning, implantation, and quality assurance. Overall rates of urinary toxicity are low; however, several dosimetric variables associated with the EUS were found to correlate with urinary toxicity.
(Copyright © 2020 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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