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

Abstract

To evaluate the impact of zinc supplementation on the survival of patients after receiving radiotherapy for head and neck cancers. 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. 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). One impact seen was that zinc supplementation improved LFS at 3 years after beginning treatment for patients with Stages III-IV disease. It is imperative that these patients be followed up for a longer period to draw a definite conclusion.