Sensitivity analysis of dose-response model parameters for the bladder in prostate cancer radiotherapy

Introduction - This study evaluates how model parameter values affect dose-response maps (DRMs) in identifying high-risk bladder subregions associated with late urinary toxicities in prostate cancer patients post-radiotherapy. - Methods - Data from 1808 patients were analyzed for five late bladder t...

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Main Authors: Puri, Tanuj (Author) , Rancati, Tiziana (Author) , Seibold, Petra (Author) , Webb, Adam (Author) , osorio, Eliana Vasquez (Author) , Azria, David (Author) , Farcy-Jacquet, Marie-Pierre (Author) , Chang-Claude, Jenny (Author) , Dunning, Alison (Author) , Lambrecht, Maarten (Author) , Avuzzi, Barbara (Author) , de Ruysscher, Dirk (Author) , Sperk, Elena (Author) , Vega, Ana (Author) , Veldeman, Liv (Author) , Rosenstein, Barry (Author) , Kerns, Sarah (Author) , Talbot, Christopher (Author) , McWilliam, Alan (Author) , Hoskin, Peter (Author) , Choudhury, Ananya (Author) , West, Catharine (Author) , van Herk, Marcel (Author)
Format: Article (Journal)
Language:English
Published: November 2025
In: Physica medica
Year: 2025, Volume: 139, Pages: 1-13
ISSN:1724-191X
DOI:10.1016/j.ejmp.2025.105178
Online Access:Verlag, kostenfrei, Volltext: https://doi.org/10.1016/j.ejmp.2025.105178
Verlag, kostenfrei, Volltext: https://www.sciencedirect.com/science/article/pii/S1120179725002881
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Author Notes:Tanuj Puri, Tiziana Rancati, Petra Seibold, Adam Webb, Eliana Vasquez osorio, David Azria, Marie-Pierre Farcy-Jacquet, Jenny Chang-Claude, Alison Dunning, Maarten Lambrecht, Barbara Avuzzi, Dirk de Ruysscher, Elena Sperk, Ana Vega, Liv Veldeman, Barry Rosenstein, Sarah Kerns, Christopher Talbot, Alan McWilliam, Peter Hoskin, Ananya Choudhury, Catharine West, Marcel van Herk, REQUITE Consortium
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Summary:Introduction - This study evaluates how model parameter values affect dose-response maps (DRMs) in identifying high-risk bladder subregions associated with late urinary toxicities in prostate cancer patients post-radiotherapy. - Methods - Data from 1808 patients were analyzed for five late bladder toxicities. Baseline scores were subtracted from maximum toxicity at 12 and 24 months and dichotomized into grades ≥ 1 and ≥ 2. Bladders were segmented on computed tomography scans, and dose-surface maps (DSMs) were created on 91 × 90 voxel grids using spherical and cylindrical coordinates. Voxel doses were converted to equivalent dose in 2 Gy fractions (EQD2, α/β 1-3 Gy). Welch’s t and Mann-Whitney U equations were applied at each voxel location. Multiple comparisons were corrected via permutation testing (10-10000 iterations), and statistically significant voxels were identified using the 90th and 95th percentiles of Tmax/Umax. Sensitivity of parameters was assessed by varying one parameter at a time, with changes > 400 voxels (∼5% of 8190) classified as large and ≤ 400 as small. - Results - Urinary tract obstruction was the only toxicity significantly associated with bladder DSMs, focusing results on this outcome. After baseline adjustment and dichotomization, event/nonevent counts were 62/701 (grade≥1) and 21/742 (grade≥2; N = 763). DRM results showed large effects of toxicity grade threshold, coordinate system, statistical test equation, and Tmax/Umax thresholding. EQD2 α/β showed variable effects, large for cylindrical and small for spherical coordinates, while the number of permutations had only a small effect. - Conclusions - Parameter selection significantly influences high-risk subregion identification in DRMs, emphasizing the need for standardized parameter reporting for meaningful external comparisons.
Item Description:Gesehen am 09.12.2025
Online verfügbar: 9. Oktober 2025, Artikelversion: 9. Oktober 2025
Physical Description:Online Resource
ISSN:1724-191X
DOI:10.1016/j.ejmp.2025.105178