Assessing sensitivity of voxel-based dose-response mapping model parameters at the bladder in prostate cancer patients: Keynote lecture

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Objective: Voxel-based dose-response maps (DRM) derived from dose-surface maps (DSM), aim to identify high-risk sub-regions in organs-at-risk (OAR) for studying dose-toxicity relationship. This study assessed the sensitivity of several parameters of DRM pipeline applied to bladder in prostate cancer (PCa) patients undergoing radiotherapy. Methods: 1808 PCa patients from REQUITE trial were included. The bladders were segmented on planning CT scans, dose surface values extracted, spatially normalised using cylindrical and spherical coordinates with a 91x90 voxel grid, doses converted to equivalent doses in 2 Gy fractions (EQD2) with α/β ratios of 1, 2 and 3 Gy. Five late toxicities (urinary tract obstruction, incontinence, frequency, urgency and retention) were normalised to baseline and dichotomised at grades 1 or 2. Binary analysis of DSMs was performed based on dichotomised toxicity values (0’s & 1’s). DSMs were analysed voxel-wise using Welch's t-test and Mann-Whitney U test with permutation testing with 10, 100, 1000 and 10000 iterations, and the maximum test statistics (Tmax) thresholded at 90th and 95th percentiles to identify statistically significant voxels associated with specific toxicities. Results: The significant voxels identified on bladder changed with grade dichotomisation (due to changes in the number of events included), coordinate system, statistical test and Tmax thresholding. α/β ratios and permutation testing showed small changes in the results. Conclusion: The choice of parameter value strongly impacts the identification of high-risk sub-regions on DRMs. All parameters within DRM pipeline should be reported in manuscripts to facilitate external result validation.
Original languageEnglish
Title of host publicationComputational Oncology and Personalized Medicine (COPM 2024) - Gliwice, Poland
Publication statusPublished - 22 May 2024
EventComputational Oncology and Personalized Medicine (COPM 2024)
- Gliwice, Poland
Duration: 22 May 202422 May 2024

Conference

ConferenceComputational Oncology and Personalized Medicine (COPM 2024)
Country/TerritoryPoland
CityGliwice
Period22/05/2422/05/24

Fingerprint

Dive into the research topics of 'Assessing sensitivity of voxel-based dose-response mapping model parameters at the bladder in prostate cancer patients: Keynote lecture'. Together they form a unique fingerprint.

Cite this