Subjective and objective assessments of sweet, umami, and bitter tastes after brachytherapy for patients with tongue cancer

Abstract

AbstractAimThe aim of this study is to investigate subjective symptoms and expression of receptors for sweet, umami, and bitter tastes after brachytherapy in patients with tongue cancer.MethodsPost‐brachytherapy changes in taste were investigated both subjectively (visual analog scale [VAS] score) and objectively (expression of taste receptors) through 37 examinations on 10 patients who received brachytherapy for treatment of tongue cancer at our hospital. The VAS was scored on a scale of 0–100. A VAS score of ≥90 was considered to indicate restoration of taste. For taste receptor expression, taste cells were collected from the brachytherapy (BRT) and non‐brachytherapy (non‐BRT) sides of the tongue, which were separated in the middle of the dorsum of the tongue, and evaluated by the ratio of the expression level of one side to the other. The mRNA expression levels of taste receptors were classified into three groups according to the number of days after BRT: ≤99, 100–299, and ≥300 days.ResultsThe number of days to a post‐brachytherapy VAS score of 90 or more was 284, 308, and 308 days for sweet, umami, and bitter tastes, respectively. Taste receptor expression was compared in three groups by number of days after radiotherapy: ≤99, 100–299, and ≥300, and no statistically significant differences were found among the tastes.ConclusionThe VAS scores showed that these tastes recovered approximately 300 days after brachytherapy. The ratio of taste receptor expression levels varied widely, and no specific indications of changes in taste receptor expression over time were obtained.