Late effects of childhood cancer treatment on the thyroid gland

Late Effects of Childhood Cancer Treatment on the Thyroid GlandIn this study, late side effects of childhood cancer treatment on the thyroid gland havebeen investigated and identified risk factors for the development of thyroid disorder, inpediatric relapse-free 120 (84 male, 36 female) patients treated between 1992-2010 years.Patients were subgrouped into two treatment groups: chemotherapy only (Group 1),chemotherapy with radiotherapy (head/neck/thorax) (Group 2). Serum TSH, fT4, tT4, anti-TPO, anti-TG, TG levels and thyroid gland ultrasound examinations were evaluated in bothgroups. According to the results, 32 (26.6%) patients had hypothyroidism, 27 (22.5%) patientshad thyroid nodules, 40 (33.3%) patients had thyroid parenchyma heterogeneity, 36 (30%)patients had high thyroid autoantibody levels, 3 (2.5%) patients had thyromegaly and 3(2.5%) patients had secondary thyroid cancer. Hypothyroidism was seen only in patients ingroup II (p <0.001), and according to diagnoses in these patients the HD 7-fold (p <0.001),brain tumors 7.9-fold (p = 0.01) and nasopharyngeal cancer 12.4-fold (p = 0.01) increased riskof developing hypothyroidism. It can be seen that the risk of hypothyroidism was higher inpatients with receiving mantle field (p = 0.004) and neck region (p <0.001) RT with 5000-5999 cGy (p = 0.01) radiation doses. The incidence of thyroid nodules in Group II weresignificantly higher than in Group 1 (p <0,001). The diagnosis of HD 5.4-fold (p <0.001),receiving mantle field RT 11.5-fold (p = 0.03) and 4000-4999 cGy radiation dose 10.3-fold (p= 0.006) increased risk of developing thyroid nodules. There was no significant differences between groups in rates of heterogeneity of the thyroid gland, but heterogeneity of the thyroidgland was more frequent in patients diagnosed nasopharyngeal cancer (p = 0.003) treated withplatinum containing chemotherapy (p = 0.006), and received neck + nasopharynx field RT (p= 0.001). Also there was no significant differences between groups in rates of thyroid autoantibodies, but females 2,5 times more likely to develop autoimmune thyroid disordercompared to boy and patients received facial area RT (p = 0.02) with 5000-5999 cGy dose (p= 0.02) and treated with platinum containing chemotherapy group (p = 0.02) were at risk ofdeveloping thyroid autoantibodies.Although thyroid dysfunction has been recorded in patients received platinum containingchemotherapy group,they also received RT at the same time. As a result, application of onlychemotherapy were not constitute a risk for thyroid disorder.