ESTRO 2024 - Abstract Book

S1343

Clinical - Head & neck

ESTRO 2024

Keywords: Nasopharyngeal cancer, radiomic quality scoring

1810

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Reduction of side effects by protecting the tongue as organ at risk: a planning-/feasibility study.

Andrea Renate Glasmacher, Thomas Müdder, Lara Caglayan, Younèss Nour, Eleni Gkika, Christina Leitzen

University Hospital Bonn, Department of Radiation Oncology, Bonn, Germany

Purpose/Objective:

Despite the technological progress, radiotherapy of patients with head and neck tumors is associated with high rates of side effects. Besides the toxicity of skin and mucosa, changes or loss of taste are experienced as burdensome by patients. In combination with dysphagia, nausea and emesis, dysgeusia often leads to malnutrition and weight loss. The quality of life is limited. Because of weight loss, changes in anatomy occur and the precision of radiation gets worse so that adaptive planning is necessary. We know through previous study results, that the dose delivered at the tongue is directly correlated to the emergence of changes in taste. Thus, a dose reduction at the tongue might lead to a decrease of these side effects. The aim of this planning study was to find out, if it is possible to create treatment plans, which include a protection of the tongue while not worsen the coverage of the PTV or the protection of other organs at risk.

Material/Methods:

We retrospectively created new treatment plans (Simulation) in 20 patients, who have been irradiated definitely or adjuvantly due to a head and neck tumor. The tongue was marked as an organ of risk in these new plans under the condition that the tumor was not located in the tongue and respectively the tongue was not part of the PTV. The tongue was separated in thirds (anterior, medial and posterior part). In our study, patients were irradiated either at Tomotherapy (Accuray Incorporated, Sunnyvale, CA, USA) or at TrueBeam ™ STx (Varian Medical Systems, Inc., Palo Alto, CA, USA). Treatment planning software for Accuray was "Tomotherapy Hi- Art II" and for Varian was „Eclipse“ (v15.6). Initial irradiations were performed as IG-/IMRT without concrete protection of the tongue.

Results:

1. Dose exposure to the tongue

The tongue could be spared significantly better by defining it as an organ of risk. This effect was especially seen in the anterior and medial part of the tongue. In addition, the posterior part had a better protection without being statistically significant.