Endocrine Abstracts

Medulloblastoma is the most common malignant brain tumor in childhood. Treatment of medulloblastoma includes surgery, radiation therapy and chemotherapy. Craniospinal radiation can cause adverse effects on the endocrine system, specifically on the hypothalamic-pituitary axis. Increasing survival rates of pediatric patients with brain tumors lead to increased concern regarding long-term quality of life, including the detection and correction of endocrine disorders. One of the most frequent signs of endocrine dysfunction is growth and/or growth velocity retardation. We present data of growth hormone secretion in 28 patients with medulloblastoma after combined treatment (including craniospinal radiation). There were 20 boys (71.4%) and eight girls (28.6%). The mean age at time of examination was 10.2±2.75 yrs (6.2–15.5) The mean age of disease onset was 6.4±2.8 yrs (ranged from 1.1 to 13 yrs) and the time from end of therapy to our examination was 4.36±2.43 (0.5–13.4) yrs. Height SDS at the moment of examination (adjusted to age and sex) was −1.25±0.9 (−3.35 ÷ 0,21). Growth velocity did not exceed 2.5–3 cm/year in most patients. Growth hormone secretion was assessed by GH-stimulation test (clonidine or insulin). Total growth hormone deficiency was observed in 26/28 patients (92.9%), another two patients had partial GH-deficiency. Mean IGF-1 S.D.S. level (adjusted for sex, age and Tanner stage) was −1.35±0.9 (−5.2 ÷ 1.22), nevertheless 64.28% of patients (18/28) had normal IGF-1 level (i.e. IGF-1 SDS level from +1.2 to −2).

Conclusion: In the group of children, treated for medulloblastoma (including craniospinal therapy) we received growth hormone deficiency (total or partial) in 100% of patients, whereas 64.28% of them had normal IGF-1 level. We conclude that all patients with a history of craniospinal radiation should be screened for growth hormone deficiency. IGF-1 level cannot serve as a sensitive additional marker in this case.