Long-Term Taste Impairment after Intensity-Modulated Radiotherapy to Treat Head-and-Neck Cancer: Correlations with Glossectomy and the Mean Radiation Dose to the Oral Cavity

We explored the effects of various parameters on taste impairments (TIs) in head-and-neck (H&N) cancer patients receiving intensity-modulated radiotherapy (IMRT). From January 2014 to September 2017, 88 H&N cancer patients subjected to curative or postoperative IMRT were enrolled in this prospective study. All patients underwent at least 1 year of follow-up after IMRT. Quality-of-life assessments in terms of patient-reported gustatory function were measured using the taste-related questions of the European Organization for Research and Treatment of Cancer H&N35 questionnaires. At a median follow-up time of 27 months, 27 of 88 patients (30.7%) reported long-term TIs. In multivariate analyses, glossectomy most significantly predicted TIs (P = 0.04). The percentage of TIs (61.5%) was significantly (P = 0.03) higher in patients who underwent partial or total glossectomy than in patients who did not undergo surgery (28.0%) and those who underwent radical surgery without glossectomy (20.0%). When we excluded surgical patients from analyses, the mean radiation dose to the oral cavity was of borderline significance in terms of TI prediction (P = 0.05). Only 14.3% of patients suffered from TIs when the mean radiation dose was <5000 centi-Gray (cGy) compared with 28.3% when the mean dose was ≥5000 cGy. In conclusion, glossectomy is the major cause of long-term TIs in H&N cancer patients receiving IMRT. In patients who do not undergo glossectomy, reduction of the mean radiation dose to the oral cavity may reduce TIs after IMRT.