ABSTRACT
Because of prevalence of head and neck cancer and extensive surgery in this area, complementary therapies in these patients are of particular importance. One of the most important complementary therapies is head and neck radiation therapy after surgery. Radiation therapy in head and neck can interfere on the thyroid gland function. The aim of this study is to determine the relationship between head and neck cancer radiotherapy and thyroid function after surgery. This study is an analytical epidemiological study on all patients who admitted for head and neck surgery in Imam Khomini hospital in 2007-2008. These patients candidate for complementary radiotherapy postoperatively. Exclusion criteria include: total for partial thyroidectomy, impaired thyroid function before radiotherapy and patients with a history of thyroid dysfunction. Levels of thyroid hormones [T3, T4, TSH] is recorded before and after radiotherapy. Age, sex, hormone levels before and after radiotherapy and the number of patients with hypothyroidism are reviewed. There was 60 patients, 34 women [56.6%] and 26 male [43.3%]. The mean age was 58.5 years, SD was 12.3. Thyroid tests in all patients were reported normal. Average amount of Total T3 before radiation therapy was 2.83 +/- 1.2 and after radiation therapy 1.74 +/- 0.9. P value level was 0.012. Average Total T4 levels before radiotherapy was 87.5 +/- 23.4 and after radiotherapy was 65.3 +/- 26.2. P value level was 0.003. Mean TSH levels before radiotherapy was 2.45 +/- 1.7 and after radiotherapy was 5.7 +/- 3.3. P value level was 0.000. 23 patients of 60 patients were hypothyroid [38%].There is a relationship between head and neck radiotherapy and hypothyroidism. We recommended controlling thyroid hormone function before and after treatment and then annually and also treating hypothyroidism if it occurred