Background: In uncontrolled clinical trials, the administration of oral zinc sulfate has been reported both to prevent and correct taste abnormalities in cancer patients receiving external radiotherapy (ERT) to the head and neck region.
Methods: Eighteen patients were randomized to receive either zinc sulfate tablets (a dose of 45 mg) or placebo tablets three times a day at the onset of subjective perception of taste alterations during the course of ERT and up to 1 month after ERT termination. Taste acuity was determined by measuring detection and recognition thresholds for four taste qualities. Intolerance of zinc sulfate or placebo administration was investigated, and the oral cavity was examined. All the evaluations were studied prior to, at weekly intervals during, and 1 month after ERT administration.
Results: Taste acuity for one or more taste qualities was already impaired before ERT. During ERT treatment, taste alterations were experienced at least once for a minimum of 3 of the 8 measured thresholds by 100% of the patients, and 33.3% of the patients became aware of some alteration within the first week of treatment. The patients treated with placebo experienced a greater worsening of taste acuity during ERT treatment compared with those treated with zinc sulfate. One month after ERT was terminated, the patients receiving zinc sulfate had a quicker recovery of taste acuity than those receiving placebo. Statistically significant differences between the two groups emerged for urea detection and sodium chloride recognition thresholds during ERT treatment and for sodium chloride, saccharose, and hydrogen chloride recognition thresholds after the termination of ERT treatment.
Conclusions: This pharmacologic therapy is effective and well tolerated; it could become a routine in clinical practice to improve the supportive care of patients with taste alterations resulting from head and neck cancer.