Comparative evaluation of serum zinc level in head and neck cancer patients before and after radiation therapy.

Background: Head and neck cancers (HNCs) include 5.3% of all cancers and they are the cause of the same 5.3% of cancer deaths. Oxidative stress has a crucial role in cancer progression and cancer therapy. Ionizing radiation causes cell malfunction and death by creating reactive oxygen species. Due to its antioxidant activity, immune system power enhancement and role in apoptosis, zinc is a crucial trace element in oncology including HNCs. We decided to compare serum zinc level of HNC patients before and after RT, to assess the potential effects of ionizing radiation therapy on serum zinc. Methods: Fifty-seven HNC patients, who were candidates for curative radiation therapy (RT), were enrolled and their serum zinc level just before and 2 months after completion of RT were checked in a single laboratory. RT was prescribed by linear accelerator with 60 to 70 Gy by conventional method. Data were analyzed by SPSS 20. Results: Mean serum zinc prior to RT and following RT were 77.64±13.45 mg/dl and 68.28±11.93 mg/dl, respectively, which was lower following RT (p<0.001). Patients' sex, age and duration from diagnosis to treatment and site of disease didn't have any impact on serum zinc difference. Conclusion: This study showed that RT of HNCs leads to serum zinc reduction, which is greater in nodal disease because of either larger field or higher dose of radiation. Taking zinc supplements while being treated by RT, may be necessary.