Selenium substitution during radiotherapy in head and neck cancer

Objective: The substitution of selenium effects in activation of the selenium dependent enzyme glutathione peroxidase which is important for scavenging free radicals. Until today only limited data was available about the clinical impact of selenium regarding the toxicities due to free radical producing therapies, e.g. irradiation or chemotherapy. Material and methods: 39 patients (8 female, 31 male) with advanced head neck cancer were included to a randomized Phase 11 study. The mean age was 63.52 +/- 9.31 years. Tumor localizations: oral cancer 15 patients, oropharynx 19 patients, hypopharynx 5 patients, CUP I patient. Group A (n = 22) received 500 mu g sodium selenite at the days of radiotherapy and 300 mu g sodium selenite at holidays or weekend. Group B (17) was irradiated without any selenium substitution. Both groups were well balanced according age, gender, localization and stage of the tumor. We evaluated the RTOG grade of radiation-associated toxicities once per week. Results: We observed the following serious toxicities (Group A versus Group B): dysphagia 22.7% vs. 35.3%, loss of taste 22.7% vs. 47.1%, dry mouth 22.7% vs. 23.5%, and stomatitis 36.4% vs. 23.5%. A statistical trend (Fisher's exact-test) is only seen ill the area of loss of taste (p = 0,172). The analysis per week (Student t-test) had shown a significant reduction of dysphagia in the selenium group at the last week of irradiation. Conclusion: The small randomized trial has shown limited effects of selenium in the prevention of ageusia (loss of taste) and dysphagia due to radiotherapy because of head and neck cancer.