Effects of zinc supplementation on clinical outcomes in patients receiving radiotherapy for head and neck cancers: A double-blinded randomized study

Purpose: To evaluate the impact of zinc supplementation on the survival of patients after receiving radiotherapy for head and neck cancers. Methods and Materials: Patients were randomly divided into two groups; experimental and control. Patients in the experimental group received a predetermined dose of a zinc supplement, and the control group, a placebo. The 50 patients in each group could be considered homogenous with respect to medical histories, tumor characteristics, and therapeutic details. Results: Patients in both groups appeared to have similar results for 3-year overall, disease-free, and metastases-free survival rates (p = 0.19, p = 0.54, and p = 0.35, respectively). However, patients in the experimental group had better 3-year local-free survival (LFS), although the difference was only marginal (p = 0.092). Another difference was that patients in the experimental group with Stages III-IV disease had a much better 3-year LFS rate when they received concurrent chemoradiotherapy (p = 0.003). Conclusions: One impact seen was that zinc supplementation improved LFS at 3 years after beginning treatment for patients with Stages IH-IV disease. It is imperative that these patients be followed up for a longer period to draw a definite conclusion. (C) 2008 Elsevier Inc.