The effects of oral zinc sulphate during radiotherapy on anti-oxidant enzyme activities in patients with head and neck cancer: A prospective, randomised, placebo-controlled study

Summary The purpose was to determine the effects of oral zinc sulphate along with radiotherapy on anti‐oxidant enzyme activities in patients with head and neck cancer. Thirty patients with head and neck cancer were randomly assigned to receive either zinc sulphate capsules (including 50 mg zinc) (n = 15) or placebo (n = 15) three times a day, starting on the day of the first radiotherapy fraction and continuing throughout the scheduled radiotherapy course including weekends and 6 weeks after radiotherapy. The patients were treated with telecobalt radiation at conventional fractionation of 2 Gy/fraction and five fractions/week in 20–35 fractions for a period of 4–7 weeks. Blood samples for biochemical parameters were collected after an overnight fast (12 h) before radiotherapy, the first day and 6 weeks after radiotherapy. In the placebo group, three patients were excluded. No difference was detected in any final measurement activities of erythrocyte anti‐oxidant enzyme such as copper‐zinc superoxide dismutase (Cu‐Zn SOD), catalase (CAT) and glutathione peroxidase (GSH‐Px) in the direct comparison between the zinc sulphate and the placebo group, except erythrocyte SOD activities measured the first day after radiotherapy (p