Complications thyroïdiennes après greffes de cellules souches hématopoïétiques dans l’enfance

Abstract

To evaluate the percentage and risk factors of thyroid dysfunction in 79 children who underwent bone marrow transplantation in a single centre. Patients and methods. – The mean age of the cohort was 6.8 and mean follow-up 5.5 years. The 79 patients were divided in two groups according to the pretransplant conditioning regimen: fractionated total body irradiation (TBI)( N =54), chemotherapy with Busulphan ( N =25). Thyroid function was evaluated by thyroid-stimulating hormone (TSH) and free thyroxine (fT4) tests. Overt hypothyroidism was defined by low fT4 blood levels and TSH > 4mU/l, and compensated hypothyroidism by normal fT4 index and TSH >4mU/L. Results. – The six-year probability of hypothyroidism was 36 ±6% for the whole group of 79 patients, 49 ±8% after TBI and 9 ±6% in the Busulphan group ( P <0.001). Neither gender, nor primary disease, nor presence of graft versus host disease were found to be statistically significant for occurrence of hypothyroidism in the TBI group. However, a younger age seemed to influence statistically the 6-year probability of hypothyroidism in the TBI group: 59 ±9% if age <7.7 years versus 34 ±13% if age >7.7 years ( P =0.02). Conclusion. – A careful follow-up of thyroid function is recommended even without TBI conditioning regimen. Young age as a potential risk factor of hypothyroidism has never been described and needs to be studied in a larger cohort.