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.