Quantitative evaluation of taste dysfunction using electrogustometry in patients with head and neck cancer undergoing intensity-modulated radiation therapy and intensity-modulated proton therapy.

Taste disorders are common adverse events in patients undergoing radiotherapy (RT) for head and neck cancer (HNC), significantly impairing quality of life. This study was performed to quantitatively evaluate taste function using electrogustometry (EGM) in patients treated with intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT). This retrospective study included 18 patients with HNC (15 men, 3 women; median age 61 years) treated with IMRT or IMPT. EGM and patient-reported taste questionnaires were assessed at baseline, completion of RT and 3, 6, and 12 months post-treatment. EGM thresholds were measured bilaterally at tongue sites using standardized protocols. All patients completed EGM assessments, while questionnaire data were partially missing at treatment completion. Longitudinal changes in objective and subjective taste function were analyzed to evaluate radiation-induced taste dysfunction and recovery patterns over 1 year. Patient-reported taste scores showed significant longitudinal changes across five time points (P < 0.001), worsening at completion of RT and gradually recovering thereafter. EGM thresholds also changed significantly over time (P < 0.001), although no significant effects of treatment group or interaction were observed. No significant differences between IMRT and IMPT groups were found for changes from baseline except at 12 months (P = 0.04). In this exploratory study, EGM demonstrated significant time-dependent changes in taste function after RT for HNC, with no significant differences between IMRT and IMPT in the primary analysis. IMPT showed a trend toward milder dysfunction, but findings are preliminary and require confirmation in larger prospective studies.