Related Experiment Video
Updated: Jun 19, 2025
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Comparison of stereotactic radiotherapy and protons for uveal melanoma patients
Emmanuelle Fleury1,2, Jean-Philippe Pignol3, Emine Kiliç4,5
1Erasmus Medical Center Cancer Institute, University Medical Center, Department of Radiotherapy, Rotterdam, The Netherlands.
Background And Purpose:
Uveal melanoma (UM) is the most common primary ocular malignancy. We compared fractionated stereotactic radiotherapy (SRT) with proton therapy, including toxicity risks for UM patients.
Materials And Methods:
For a total of 66 UM patients from a single center, SRT dose distributions were compared to protons using the same planning CT. Fourteen dose-volume parameters were compared in 2-Gy equivalent dose per fraction (EQD2). Four toxicity profiles were evaluated: maculopathy, optic-neuropathy, visual acuity impairment (Profile I); neovascular glaucoma (Profile II); radiation-induced retinopathy (Profile III); and dry-eye syndrome (Profile IV). For Profile III, retina Mercator maps were generated to visualize the geographical location of dose differences.
Results:
In 9/66 cases, (14 %) proton plans were superior for all dose-volume parameters. Higher T stages benefited more from protons in Profile I, especially tumors located within 3 mm or less from the optic nerve. In Profile II, only 9/66 cases resulted in a better proton plan. In Profile III, better retina volume sparing was always achievable with protons, with a larger gain for T3 tumors. In Profile IV, protons always reduced the risk of toxicity with a median RBE-weighted EQD2 reduction of 15.3 Gy.
Conclusions:
This study reports the first side-by-side imaging-based planning comparison between protons and SRT for UM patients. Globally, while protons appear almost always better regarding the risk of optic-neuropathy, retinopathy and dry-eye syndrome, for other toxicity like neovascular glaucoma, a plan comparison is warranted. Choice would depend on the prioritization of risks.
