935 THYROID ABNORMALITIES IN LONG-TERM SURVIVORS OF CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA (ALL)

Abstract

175 long-term survivors of childhood ALL were studied for thyroid function (thyroid stimulating hormone, triidothyronine resin uptake and thyroxine). Patients (pts) were diagnosed between 1972-1974 and treated on CCSG studies 101/143. Induction and maintenance chemotherapy was identical for all pts. Central nervous system therapy consisted of either 1800 or 2400 rad of cranial radiation (C-RT) or craniospinal (CS-RT). The 81 males and 94 females were first evaluated 7 yrs from the time of diagnosis and have been studied annually for an average of 2.1 yrs. Pts had a mean age of 5.3 yrs at diagnosis and all had discontinued therapy. 17/175 (10%) were identified to have thyroid function abnormalities. 5 pts (3%) had primary hypothyroidism of whom one developed thyroid carcinoma. Compensated hypothyroidism was found in 11 (6%) of whom 8 became euthyroid without replacement therapy while 3 pts remain compensated for 2, 3 and 3 years. 1/175 pts was found to have transient hyperthyroxinemia. One pt with normal thyroid function studies developed a thyroid adenoma. The frequency of thyroid hypofunction was more common in females (12.8%) vs males (4.9%), p=0.07. No significant association was observed between thyroid hypofunction and radiation field (CS-RT vs C-RT), dose of radiation, duration of chemotherapy or age at radiation. This study found that 10% of pts had thyroid function abnormalities with compensated but temporary hypothyroidism being most common.