Dose-volume analysis of planned versus accumulated dose as a predictor for late gastrointestinal toxicity in men receiving radiotherapy for high-risk prostate cancer.

Ong, ALK; Knight, K; Panettieri, V; Dimmock, M; Tuan, JKL; Tan, HQ; Wright, C

Abstract

Background and purpose: Significant dose deviations have been reported between planned (DP) and accumulated (DA) dose in prostate radiotherapy. This study aimed to develop multivariate analysis (MVA) models associating Grade 1 and 2 gastrointestinal (GI) toxicity with clinical and DP or DA dosimetric variables separately. Materials and methods: Dose volume (DV) metrics were compared between DA and DP for 150 high-risk prostate cancer patients. MV models were generated from significant clinical and dosimetric variables (p < 0.05) at univariate level. Dose-based-region of interest (DB-ROI) metrics were included. Model performance was measured, and additional subgroup analysis were performed. Results: Rectal DA demonstrated a higher intermediate-high dose (V30-65 Gy and DB-ROI at 15-50 mm) compared to DP. Conversely, at the very high dose region, rectal DA (V75 Gy and DB-ROI at 5-10 mm) were significantly lower. In MVA, rectal DB-ROI at 10 mm was predictive for Grade = 1 GI toxicity for DA and DP. Age, rectal DA for D0.03 cc, and rectal DP for DB-ROI 10 mm were predictors for Grade 2 GI toxicity. Subgroup analysis revealed that patients = 72 years old and a rectal DA of = 78.2 Gy were highly predictive of Grade 2 GI toxicity. Conclusions: The dosimetric impact of a higher dose rectal dose in DA due to volumetric changes was minimal and was not predictive of detrimental clinical toxicity apart from rectal D0.03 cc = 78.2 Gy for Grade 2 GI toxicity. The use of the DB-ROI method can provide equivalent predictive power as the DV method in toxicity prediction.

Citation

Ong, A., Knight, K., Panettieri, V., Dimmock, M., Tuan, J., Tan, H., & Wright, C. (2022). Dose-volume analysis of planned versus accumulated dose as a predictor for late gastrointestinal toxicity in men receiving radiotherapy for high-risk prostate cancer. https://doi.org/10.1016/j.phro.2022.07.001

• Acceptance Date: Jul 6, 2022
• Publication Date: Jul 16, 2022
• Journal: Physics and Imaging in Radiation Oncology
• Print ISSN: 2405-6316
• Pages: 97 - 102
• DOI: https://doi.org/10.1016/j.phro.2022.07.001
• Keywords: Accumulated dose; Predictive model; Gastrointestinal toxicity; High-risk prostate; Volumetric image-guidance
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S2405631622000641