Treatment for acute lymphoblastic leukemia in children is associated with papillary carcinoma of thyroid, but not with thyroid disfunction.
OBJECTIVE
The treatment of acute lymphoblastic leukemia (ALL) in children may cause sequelae, some appearing only at long-term follow-up. We investigated the thyroid gland morphology and the function of the pituitary-thyroid axis in a group of patients treated for ALL in childhood.


METHODS
A cohort study was conducted at a tertiary medical center. Thirty-three children (22 males and 11 females; age: 11.9+/-3 years; range: 6 to 18 years) were studied. The mean age at the time of chemotherapy and prophylactic cranial irradiation (12-24 Gy) was 5.5+/-2.6 years (range: 1 to 14 years). The average length of the follow-up was 6.1+/-3 years (range: 2 to 12 years). Thyroid morphology (n=33) was evaluated by palpation and ultrasonography. Thyroid function (n=30) was evaluated measuring total T3 and T4, and by the thyrotrophin-releasing hormone (TRH) test. Prolactin secretion was assessed before and after injection of TRH to evaluate the diagnostic test accuracy.


RESULTS
One out of the 33 children (3%) was found to have a papillary carcinoma of thyroid four years after ALL treatment. Thyroid function was normal in all the patients, however one case (3%) showed high TSH (9.2 microU/mL) and prolactin (37.5 ng/mL) basal levels, but normal responses to TRH (TSH = 17.8 microU/mL; prolactin = 82.3 ng/mL). These hormonal alteration were not confirmed at follow-up: TSH = 1.6 microU/mL and prolactin = 13.7 ng/mL.


CONCLUSIONS
In this cohort of patients, the treatment of ALL was associated with one case of thyroid carcinoma, but it did not produce adverse effect on the thyroid function, at least after a follow-up lasted on average 6 years.
Neves Mascarenhas
A
A
Endocrinology Service, Hospital Regional da Asa Norte, Brasília, Brazil.
Papadia
C
C
Alves Aquino
C
C
Oba
L
L
Ferreira
M
M
Casulari
L A
LA
D000293:Adolescent; D002291:Carcinoma, Papillary / Q000097:blood* / Q000209:etiology*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D016609:Neoplasms, Second Primary / Q000097:blood* / Q000209:etiology*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000628:therapy*; D013961:Thyroid Gland / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D013964:Thyroid Neoplasms / Q000097:blood* / Q000209:etiology*; D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine