Magnetic resonance imaging of the pituitary area in children treated for acute lymphoblastic leukemia with low-dose (18-Gy) cranial irradiation. Relationships to growth and growth hormone secretion.

Objective: To determine the effects of 18-Gy cranial irradiation on growth, growth hormone (GH) secretion, and pituitary magnetic resonance imaging in children who underwent previous irradiation for treatment of acute lymphoblastic leukemia.

Design: Clinical survey.

Setting: Department of Pediatrics of the University of Bologna (Italy).

Patients: Ten boys and 18 girls who were treated for acute lymphoblastic leukemia; median age at diagnosis was 3.1 years and at the end of follow-up was 11.5 years.

Measurements And Results: Height was periodically measured from diagnosis until the end of follow-up, when GH secretion study and magnetic resonance imaging were performed. The mean height SD score was significantly lower than at diagnosis only at the end of treatment. Nocturnal mean GH concentration and GH response to pharmacological tests (arginine and levodopa [L-dopa]) were pathological in 22 cases (81.5%) and 18 cases (64.3%), respectively. Sixteen cases (59.2%) had a blunted GH release to the three tests. Mean pituitary anterior lobe height was reduced and seven subjects (25%) showed an empty sella.

Conclusions: Cranial irradiation with 18 Gy does not seem to influence the growth pattern of most children who are treated for acute lymphoblastic leukemia, despite severe impairment of GH secretion and morphological abnormalities of the sellar area. However, a follow-up until final height is necessary.