In Silico Dosimetric Comparison of Intensity-Modulated Photon Versus Proton Therapy for Pelvic and Para-Aortic Nodal Recurrence of Prostate Cancer Following Prior Irradiation
- 1Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- 2Department of Radiation Oncology, University of Florida College of Medicine, Jacksonville, FL 32206, USA
- 3Department of Radiation Oncology, University of South Florida Morsani College of Medicine, Tampa, FL 33606, USA
Abstract
Background/Objectives: Limited data exists comparing photon-based intensity-modulated (IMRT) or volumetric modulated arc therapy (VMAT) against intensity-modulated proton therapy (IMPT) when treating pelvic or para-aortic nodal recurrences of prostate cancer following prior irradiation. The aim of this study was to evaluate dosimetric differences between VMAT and IMPT when treating nodal recurrences in the re-irradiation setting. Methods: VMAT and IMPT plans for 15 patients with node-recurrent disease were evaluated. Prescription doses to the whole pelvis and prostate bed planning target volumes (PTVs) from the initial VMAT plans were 45–50.4 Gy and 66.6–72 Gy, respectively. IMPT re-irradiation prescription doses were 45–53.75 Gy radiobiological equivalent (GyE) (proton radiobiological effective dose 1.1) to at-risk pelvic and para-aortic nodal chains and 60–64 GyE to gross nodal disease. For re-planning and comparative study purposes, clinical target volume (CTV) prescription doses were standardized to 50.4 Gy for the regional pelvic and para-aortic nodes, and 63 Gy for the grossly involved nodal disease. Organ-at-risk (OAR) contours were standardized and re-irradiation plans were generated on Raystation. Student’s t-test was used to compare CTV coverage and dose to OARs. Results: CTV coverage was met for all plans, with 99% of CTVs receiving ≥99% of prescription doses. Composite analysis demonstrated IMPT not only sustained dosimetric benefits in the re-irradiation setting for all OARs except sigmoid but also conferred significant advantages. Select endpoints with significant differences on composite analysis included bowel cavity V45Gy, left kidney V18Gy and mean dose, right kidney V18Gy and mean dose, and integral dose to ‘Body-CTV’. Conclusions: Composite analysis of the initial treatment and re-irradiation plans showed that IMPT delivered and maintained significant OAR dose reductions in the nodal re-irradiation setting, potentially decreasing the risk of long-term toxicities. This provides a rationale for the utilization of IMPT in this clinical setting.
Related
- Dosimetric Comparison of Intensity-Modulated Radiotherapy and Four-Field Three-Dimensional Conformal Radiotherapy in the Management of Prostate Cancer: A Retrospective Dual-Centre Analysis
- Dosimetric Comparison of One-, Two-, Three-, and Four-Arc Volumetric Modulated Arc Therapy Plans in Cervical Carcinoma: Evaluation of Plan Quality, Organ-at-Risk Sparing, and Treatment Efficiency.
- Fictive Field-based Feathering for Extended-SSD Total Body Irradiation: A Single-institution Planning and Dosimetric Analysis
- Comparative Dosimetric Evaluation of Tomotherapy with a 1-cm Field Width versus Volumetric-modulated Arc Therapy for Whole-brain Radiotherapy with Hippocampal Avoidance
- Dosimetric Outcomes of Definitive Radiation Therapy to Anal Squamous Cell Carcinoma in a Single Institution Using Volumetric Modulated Arc Therapy Evaluated Against Australian and International Treatment Planning Guidelines
BibTeX
@article{knight2026silico,
title = {{In Silico Dosimetric Comparison of Intensity-Modulated Photon Versus Proton Therapy for Pelvic and Para-Aortic Nodal Recurrence of Prostate Cancer Following Prior Irradiation}},
author = {James A. Knight and Hao Chen and Anh Tran and Bethlehem Floreza and Heng Li and Aditya Halthore and Rachit Kumar and Michael Goldstein and Ana Kiess and Daniel Song and Stephen Greco and Curtiland Deville},
journal = {Cancers},
year = {2026},
month = oct,
doi = {10.3390/cancers18213452},
url = {https://www.mdpi.com/2072-6694/18/21/3452},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - In Silico Dosimetric Comparison of Intensity-Modulated Photon Versus Proton Therapy for Pelvic and Para-Aortic Nodal Recurrence of Prostate Cancer Following Prior Irradiation
AU - James A. Knight
AU - Hao Chen
AU - Anh Tran
AU - Bethlehem Floreza
AU - Heng Li
AU - Aditya Halthore
AU - Rachit Kumar
AU - Michael Goldstein
AU - Ana Kiess
AU - Daniel Song
AU - Stephen Greco
AU - Curtiland Deville
PY - 2026
DA - 2026/10/26
JO - Cancers
DO - 10.3390/cancers18213452
UR - https://www.mdpi.com/2072-6694/18/21/3452
AB - Background/Objectives: Limited data exists comparing photon-based intensity-modulated (IMRT) or volumetric modulated arc therapy (VMAT) against intensity-modulated proton therapy (IMPT) when treating pelvic or para-aortic nodal recurrences of prostate cancer following prior irradiation. The aim of this study was to evaluate dosimetric differences between VMAT and IMPT when treating nodal recurrences in the re-irradiation setting. Methods: VMAT and IMPT plans for 15 patients with node-recurrent disease were evaluated. Prescription doses to the whole pelvis and prostate bed planning target volumes (PTVs) from the initial VMAT plans were 45–50.4 Gy and 66.6–72 Gy, respectively. IMPT re-irradiation prescription doses were 45–53.75 Gy radiobiological equivalent (GyE) (proton radiobiological effective dose 1.1) to at-risk pelvic and para-aortic nodal chains and 60–64 GyE to gross nodal disease. For re-planning and comparative study purposes, clinical target volume (CTV) prescription doses were standardized to 50.4 Gy for the regional pelvic and para-aortic nodes, and 63 Gy for the grossly involved nodal disease. Organ-at-risk (OAR) contours were standardized and re-irradiation plans were generated on Raystation. Student’s t-test was used to compare CTV coverage and dose to OARs. Results: CTV coverage was met for all plans, with 99% of CTVs receiving ≥99% of prescription doses. Composite analysis demonstrated IMPT not only sustained dosimetric benefits in the re-irradiation setting for all OARs except sigmoid but also conferred significant advantages. Select endpoints with significant differences on composite analysis included bowel cavity V45Gy, left kidney V18Gy and mean dose, right kidney V18Gy and mean dose, and integral dose to ‘Body-CTV’. Conclusions: Composite analysis of the initial treatment and re-irradiation plans showed that IMPT delivered and maintained significant OAR dose reductions in the nodal re-irradiation setting, potentially decreasing the risk of long-term toxicities. This provides a rationale for the utilization of IMPT in this clinical setting.
SN - 2072-6694
ER -