Thyroid dysfunction in children with leukemia over the first year after hematopoietic stem cell transplantation

Thyroid function in children with leukemia during the first year after hematopoietic stem cell transplantation (HSCT) was investigated. The medical records of 186 subjects [111 boys and 75 girls; lymphoid=75, myeloid=111; median age at HSCT was 10.7 (0.8-21.8) years old] were reviewed retrospectively. In children with leukemia, T₃ decreased at 1 month (p<0.001) and recovered 9 months to the levels before HSCT. TSH decreased at 1 month (p<0.001), recovered at 3 months and increased at 12 months (p<0.001) to the levels before HSCT. The incidence of euthyroid sick syndrome (ESS, 23.2%, 15.5%, 5.9%, 5.2%, 3.9%, p for trend <0.001) decreased and subclinical hypothyroidism (SH, 0%, 3.9%, 14.8%, 22.1%, 21.3%, p for trend <0.001) increased at 1, 3, 6, 9 and 12 months after HSCT. Out of 55 patients developing ESS during 3 months after HSCT, 54 recovered to normal thyroid function within 5 months without medication. Among the total 186 subjects, 21 patients have been treated with levothyroxine. Both height and weight standard deviation scores continued to decrease over 1 year after HSCT. In children with leukemia, one-quarter had ESS at 1 month and one-fifth had SH at 12 months and continued growth impairments were observed during 1 year after HSCT. Most of the ESS patients recovered to normal within 5 months without medication. More long-term follow-up of thyroid function and growth in children with leukemia after HSCT is crucial.