Effect of Cranial Irradiation on Pituitary Size in Patients Cured of Acute Lymphoblastic Leukaemia: Retrospective Study

KK Shing, D Roebuck, MP Yuen, KW Chik, CK Li, YL Chan

Hong Kong J Radiol 2004;7:195-8

Objective: To evaluate the pituitary glands of patients previously treated for acute lymphoblastic leukaemia with cranial irradiation.

Patients and Methods: Thirty nine patients who were cured of acute lymphoblastic leukaemia and who were regularly followed up from 1979 to 1992 were recruited. Sagittal T1-weighted magnetic resonance imaging of the pituitary gland was performed in a 1.5-T magnetic resonance machine. Sixteen age- and sex-matched patients who had been treated during childhood for solid extracranial neoplasms with systemic chemotherapy, but not intracranial irradiation, were recruited as controls.

Results: The height of the adenohypophysis was significantly smaller in patients who had had acute lymphoblastic leukaemia (mean, 3.9 mm; standard deviation, 1.2 mm) than in control patients (mean, 5.3 mm; standard deviation, 1.1 mm) [p < 0.001]. For both patients who had had acute lymphoblastic leukaemia and for controls, there was no significant correlation between pituitary height and age at diagnosis or age at the time of the study. In the group of patients who had had acute lymphoblastic leukaemia, the pituitary was shorter in those treated with more than 18 Gy of radiation (mean, 3.0 mm; standard deviation, 1.3 mm) than in those treated with exactly 18 Gy (mean, 4.1 mm; standard deviation, 1.1 mm) [p = 0.037].

Conclusion: Children cured of acute lymphoblastic leukaemia with previous cranial irradiation show a significant reduction in the height of the adenohypophysis. The effect on the size of the pituitary gland appears greater with a higher radiation dose.