The effect of head and neck irradiation on taste dysfunction: a prospective study.

Taste loss is a major cause of morbidity in patients undergoing head and neck irradiation. In a prospective study, 26 patients undergoing radical head and neck irradiation at the Royal Marsden Hospital, Sutton, and the Queen Elizabeth Hospital, Birmingham, were assessed for taste loss and xerostomia. Taste was tested using a subjective questionnaire and by objective taste testing with a series of solute solutions (sucrose, sodium chloride, urea and hydrochloric acid) at increasing concentrations, to determine the threshold level of taste sensation, both before and after radiotherapy. Xerostomia was assessed using a patient questionnaire. The volume of tongue and parotid contained within the high dose volume of the radiation treatment field was determined for each patient and correlated with the degree of objective and subjective taste loss as well as the degree of xerostomia. The results have shown that both objective (r = 0.59; P = 0.0016) and subjective taste loss (r = 0.78; P = 0.0001) was significantly associated with the proportion of tongue, but not parotid, contained within the radiation treatment field. The data gave no evidence to suggest any relationship between recovery of taste loss and volume of parotid or tongue irradiated. However, recovery of subjective taste loss, 1 month after completing radiotherapy was seen in two patients, both of whom had been treated using a wedge pair technique to avoid the contralateral area of the tongue. Changes in xerostomia were significantly correlated with the proportions of both tongue (r = 0.54; P = 0.004) and parotid (r = 0.82; P = 0.0001) within the radiation treatment fields.(ABSTRACT TRUNCATED AT 250 WORDS)