The relationship between thyroid dose and diagnosis of primary hypothyroidism in pediatric brain tumor patients receiving craniospinal irradiation.
OBJECTIVE
The aim of this work is to determine if a relationship exists between thyroid dose and incidence of primary hypothyroidism (PH) in children undergoing craniospinal irradiation (CSI).


METHODS
A total of 22 patients received CSI with evaluable thyroid dose information. All patients received concurrent chemotherapy and 21 patients (95%) received adjuvant chemotherapy. Median follow-up was 42.9 months.


RESULTS
The incidence of PH in our cohort was 59% at a median time after radiotherapy of 3.5 years (range: 8 months to 7.5 years). Mean thyroid dose appeared to best predict for PH, with a median of 2080 cGy for patients with PH versus 1736 cGy for children without PH (p=0.057). There was no association between the rate of PH and sex, age, CSI dose, minimum thyroid dose and maximum thyroid dose.


CONCLUSIONS
A relationship may exist between the mean thyroid dose and incidence of PH in patients undergoing CSI. Thus, new strategies to protect the thyroid gland may be warranted.
Christine
C
Lauro
Margaret E
ME
Macy
Philip
P
Zeitler
Jennifer
J
Backus
Pamela
P
Mettler
Nicholas
N
Foreman
Arthur K
AK
Liu
D001921:Brain / Q000528:radiation effects*; D001932:Brain Neoplasms / Q000150:complications / Q000000981:diagnostic imaging*; D002648:Child; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D011859:Radiography; D012189:Retrospective Studies; D013116:Spinal Cord / Q000528:radiation effects*; D013974:Thyroxine / Q000008:administration & dosage / Q000627:therapeutic use*
D013974:Thyroxine