Radiotherapy-induced taste impairment.

Changes in taste perception occur in a significant proportion of cancer patients. Among cancer patients treated with radiotherapy (RT) in head and neck area, the vast majority reports an altered taste sense during and after treatments. Taste impairment starts a few weeks after the beginning of irradiation, and almost all such patients experienced loss of taste acuity at a dose of 60 Gy. Some studies investigated the four basic taste intensities (sweet, salty, sour and bitter) and the umami taste, and several of these reports identified diminished threshold sensitivity for at least one taste quality. Six months to one year after RT, taste acuity recovers to its previous level in many patients, but some patients show incomplete or no recovery even several years later. Taste impairment has profound effects on patients' quality of life because is associated with weight loss through reduced appetite and altered patterns of food intake. Damage to the major salivary glands during head and neck RT leads to disturbance in taste acuity. With the implementation of new radiation techniques, such as conformal and intensity-modulated RT in head and neck irradiation, the late-radiation effects can probably be reduced, but the remaining sequelae are still bothersome to the patients.