Central hypothyroidism following chemotherapy for acute lymphoblastic leukemia.
BACKGROUND
It has been suggested that chemotherapy per se might impair the hypothalamus-pituitary-thyroid axis of childhood cancer survivors.


OBJECTIVE
We examined six patients treated for acute lymphoblastic leukemia (ALL) with chemotherapy alone, with suspicious central hypothyroidism (CH).


METHODS
ALL was diagnosed at a mean age of 3.8 years (range 0.3-6 years), the mean follow-up is 6 years (range 6-13 years). Auxological data were recorded, and thyroid function, autoimmunity and ultrasonography (US) were evaluated. Three individuals underwent a thyrotropin-releasing hormone (TRH) test and a magnetic resonance imaging (MRI) scan of the hypothalamic-pituitary region.


RESULTS
All study participants showed negative thyroid autoimmunity, normal thyroid ultrasound, and thyroid-stimulating hormone (TSH) above the normal range; free T4 (fT4) was abnormally low in two patients. After TRH infusion all patients showed TSH increase and slow TSH decline.


CONCLUSIONS
Our study shows that CH could arise at any time after childhood leukemia following only chemotherapy treatment. Although overt hypothyroidism was detected in only two patients, a careful follow-up of thyroid function is also recommended for ALL survivors not treated by irradiation.
Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy.
Federico
F
Baronio
Laura
L
Battisti
Giorgio
G
Radetti
D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000139:chemically induced*; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D013972:Thyrotropin; D013974:Thyroxine