S668
Clinical – Head & neck
ESTRO 2026
adapted based on patient-specific eye measurements and indirect tumor localization using scleral fiducials. This introduces uncertainties and can result in high doses to organs at risk. In the near future, technical developments will allow more accurate PBT planning and increase flexibility in directing the dose deposition across the eye. This opens up the possibility to choose more precisely which healthy substructure(s) of the eye will be in the beam trajectory, and how to optimize PBT planning. Since these decisions influence radiation-induced side effects, incorporating patient preferences becomes increasingly relevant. To explore patient preferences, we conducted a discrete choice experiment (DCE) to identify patient trade-offs between possible probabilities of a set of PBT In this cross-sectional observational study we invited treated and newly-diagnosed patients with choroidal melanoma to participate in our online DCE. The selection of the treatment outcomes included in the DCE was based on whether it could be modified with the PBT planning. The outcomes included: tumour recurrence, loss of eye, loss of visual field, decrease in visual acuity (VA), and pain and/or discomfort. Possible probabilities were based on the literature and/or our own cohort, in collaboration with a radiation oncologist (CR). In the DCE, patients were asked to indicate their preference between combinations of outcomes that differed in probability. The resulting DCE data were analyzed using mixed logit models, and an extension of the model using a two-class latent class logit model. It was calculated how relatively important the outcomes are given the possible probabilities. Results: treatment outcomes. Material/Methods: A total of 196 participants completed the DCE. Our results show that the risk of tumour recurrence was found most important (58%). The relative importance of loss of eye, reduced VA, pain and/or discomfort, and loss of visual field was 17%, 15%, 6%, and 3%, respectively. Conclusion: This is the first study to identify patient preferences regarding current and future hypothetical PBT planning as a function of treatment outcome in patients with choroidal melanoma. Our results show that tumour recurrence was by far the most influential factor in patients’ preferences. These findings can support future PBT planning to enable a treatment approach more tailored to patients. Keywords: Patient preferences, choroidal melanoma, proton
Digital Poster 4866 Randomized Control trial on tolerance and replanning in Shrinking Field-IMRT vs SIB-IMRT for Head and Neck Cancer: An Interim report Pradeesh Sabu 1 , Manu Mathew 1 , Jino Wilson Victor 1 , Rajendra Benny Kucipudi 1 , Swathi Bapani 1 , Megha T Philip 1 , Divya K 2 , Anjana Chandran 1 , Sharon Gikku George 1 , Timothy Peace S 1 , Finlay H 1 , Joel T 1 , Rajesh I 1 , Hannah Mary Thomas 1 , Simon Pavamani 1 , Balu Krishna Sasidharan 1 1 Radiation Oncology, Christian Medical College, Vellore, India. 2 Biostatistics, Christian Medical College, Vellore, India
Digital Poster Highlight 4956
Preferences of patients with choroidal melanoma for proton beam therapy outcomes: a discrete choice experiment Aryana Shirzada 1 , Marcel F. Jonker 2 , Nanda Horeweg 1 , Lisa E. Vlug 3 , Gre P.M. Luyten 4 , Jaco C. Bleeker 4 , Pauline A.C. Bakker 1 , Khanh Vu 4 , Marina Marinkovic 4 , Coen R.N. Rasch 1 , Arwen H. Pieterse 3 , Elske Van den Akker - Van Marle 3 1 Radiation Oncology, Leiden University Medical Center, Leiden, Netherlands. 2 Health Policy and Managment, Erasmus University, Rotterdam, Netherlands. 3 Biomedical Data Sciences, Leiden University Medical Center, Leiden, Netherlands. 4 Ophthalmolgy, Leiden University Medical Center, Leiden, Netherlands Purpose/Objective: Large and juxtapapillary choroidal melanoma can be treated with either enucleation or proton beam therapy (PBT). The latter enables preservation of the eye. Historically, PBT dose planning has relied on standard 3D computer model of an eye that is
Made with FlippingBook - Share PDF online