Evaluation of online dose-guided adaptive fractionation for intact prostate radiotherapy.
- 1Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona, USA.
- 2Department of Radiation Oncology, University of South Florida Morsani College of Medicine, Tampa, Florida, USA.
- 3Medical Artificial Intelligence and Automation Laboratory, UT Southwestern Medical Center, Dallas, Texas, USA.
Abstract
Background
Dose-guided adaptive fractionation (DGAF) was proposed as a simpler alternative of adaptive radiation therapy, using organ variation simulation for proof of concept. However, its dosimetric benefit using actual daily anatomy changes in prostate cancer patients remains unclear.Purpose
The purpose of this study was to retrospectively evaluate the dosimetric benefit and potential risk of DGAF for prostate cancer patients treated with moderately hypofractionated radiotherapy and stereotactic body radiotherapy using daily cone-beam CT.Methods
Patients assessed in this study were treated with moderately hypofractionated radiotherapy (MHRT, n = 11, 244 total fractions) and stereotactic body radiotherapy (SBRT, n = 11, 55 total fractions). The optimizer algorithm computed the desired fractional dose based on favorable or unfavorable anatomical conditions derived from daily imaging, quantified by the sparing factor threshold (μ) and spread (σ). Three methods of estimating subsequent fractionation schemes were explored. The assessment relative to patient-specific probabilities observed post-treatment includes the cohort-based probability (CBP) approach, the individual-based probability (IBP) approach, and the hybrid approach that begins as CBP and transitions to the IBP after a certain number of fractions. The benefits/risks of DGAF were assessed by calculating the equivalent dose in 2 Gy fractions (EQD2) for both the CTV and the rectum in comparison to regular fractionation.Results
DGAF demonstrated potential dosimetric benefits for intact prostate patients. The average and standard deviation of the sparing factor was 0.51 ± 0.11 for MHRT patients and 0.42 ± 0.04 for SBRT patients treated with endorectal-balloon. The hybrid approach for estimating the patients' threshold μ and spread σ outperformed other approaches assessed for both cohorts. The highest dosimetric benefit was retrospectively seen in MHRT patients where a hybrid approach were used, showing equal or decreased D15% EQD2.Conclusion
DGAF demonstrated considerable rectum sparing potential, and the benefits increased with longer fractionation and advanced approaches toward subsequent fraction estimation.
Related
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- Feasibility of reduced PTV margins in magnetic resonance image-guided online adaptive radiotherapy for bladder cancer: a personalised approach.
- Test‐time adaptation‐driven patient‐specific auto‐segmentation for CBCT‐guided online adaptive radiotherapy in cervical cancer
- Exploratory machine-learning evaluation of clinical and dosimetric features in late prostate radiotherapy toxicity.
- Development of a phantom‐based end‐to‐end QA workflow for online adaptive radiotherapy incorporating high‐resolution 2D detector measurements
BibTeX
@article{gevorkyan2026evaluation,
title = {{Evaluation of online dose-guided adaptive fractionation for intact prostate radiotherapy.}},
author = {Gevork S Gevorkyan and Libing Zhu and Riley C Tegtmeier and Diego Santos Toesca and Weiguo Lu and Mingli Chen and Yi Rong and Quan Chen},
journal = {Journal of applied clinical medical physics},
year = {2026},
month = oct,
doi = {10.1002/acm2.70865},
url = {https://europepmc.org/article/MED/42875902},
note = {CC BY},
}
RIS
TY - JOUR
TI - Evaluation of online dose-guided adaptive fractionation for intact prostate radiotherapy.
AU - Gevork S Gevorkyan
AU - Libing Zhu
AU - Riley C Tegtmeier
AU - Diego Santos Toesca
AU - Weiguo Lu
AU - Mingli Chen
AU - Yi Rong
AU - Quan Chen
PY - 2026
DA - 2026/10/01
JO - Journal of applied clinical medical physics
DO - 10.1002/acm2.70865
UR - https://europepmc.org/article/MED/42875902
AB - Background Dose-guided adaptive fractionation (DGAF) was proposed as a simpler alternative of adaptive radiation therapy, using organ variation simulation for proof of concept. However, its dosimetric benefit using actual daily anatomy changes in prostate cancer patients remains unclear.Purpose The purpose of this study was to retrospectively evaluate the dosimetric benefit and potential risk of DGAF for prostate cancer patients treated with moderately hypofractionated radiotherapy and stereotactic body radiotherapy using daily cone-beam CT.Methods Patients assessed in this study were treated with moderately hypofractionated radiotherapy (MHRT, n = 11, 244 total fractions) and stereotactic body radiotherapy (SBRT, n = 11, 55 total fractions). The optimizer algorithm computed the desired fractional dose based on favorable or unfavorable anatomical conditions derived from daily imaging, quantified by the sparing factor threshold (μ) and spread (σ). Three methods of estimating subsequent fractionation schemes were explored. The assessment relative to patient-specific probabilities observed post-treatment includes the cohort-based probability (CBP) approach, the individual-based probability (IBP) approach, and the hybrid approach that begins as CBP and transitions to the IBP after a certain number of fractions. The benefits/risks of DGAF were assessed by calculating the equivalent dose in 2 Gy fractions (EQD2) for both the CTV and the rectum in comparison to regular fractionation.Results DGAF demonstrated potential dosimetric benefits for intact prostate patients. The average and standard deviation of the sparing factor was 0.51 ± 0.11 for MHRT patients and 0.42 ± 0.04 for SBRT patients treated with endorectal-balloon. The hybrid approach for estimating the patients' threshold μ and spread σ outperformed other approaches assessed for both cohorts. The highest dosimetric benefit was retrospectively seen in MHRT patients where a hybrid approach were used, showing equal or decreased D15% EQD2.Conclusion DGAF demonstrated considerable rectum sparing potential, and the benefits increased with longer fractionation and advanced approaches toward subsequent fraction estimation.
SN - 1526-9914
ER -