Does zinc sulfate prevent therapy-induced taste alterations in head and neck cancer patients? Results of phase III double-blind, placebo-controlled trial from the North Central Cancer Treatment Group (N01C4).

Purpose: Taste alterations (dysgeusia) are well described in head and neck cancer patients who undergo radiotherapy (RT). Anecdotal observations and pilot studies have suggested zinc may mitigate these symptoms. This multi-institutional, double-blind, placebo-controlled trial was conducted to provide definitive evidence of this mineral's palliative efficacy.
Methods and Materials: A total of 169 evaluable patients were randomly assigned to zinc sulfate 45 mg orally three times daily vs. placebo. Treatment was to be given throughout RT and for 1 month after. All patients were scheduled to receive > or =2,000 cGy of external beam RT to > or =30% of the oral cavity, were able to take oral medication, and had no oral thrush at study entry. Changes in taste were assessed using the previously validated Wickham questionnaire.
Results: At baseline, the groups were comparable in age, gender, and planned radiation dose (<6,000 vs. > or =6,000 cGy). Overall, 61 zinc-treated (73%) and 71 placebo-exposed (84%) patients described taste alterations during the first 2 months (p = 0.16). The median interval to taste alterations was 2.3 vs. 1.6 weeks in the zinc-treated and placebo-exposed patients, respectively (p = 0.09). The reported taste alterations included the absence of any taste (16%), bitter taste (8%), salty taste (5%), sour taste (4%), sweet taste (5%), and the presence of a metallic taste (10%), as well as other descriptions provided by a write in response (81%). Zinc sulfate did not favorably affect the interval to taste recovery.
Conclusion: Zinc sulfate, as prescribed in this trial, did not prevent taste alterations in cancer patients who were undergoing RT to the oral pharynx.