Differential effects of 18- and 24-Gy cranial irradiation on growth rate and growth hormone release in children with prolonged survival after acute lymphocytic leukemia
A. Cicognani, E. Cacciari, V. Vecchi, M. Cau, A. Balsamo, P. Pirazzoli, M. T. Tosi, P. Rosito and G. Paolucci
Second and Third Pediatric Clinics, University of Bologna, Italy.
To evaluate the effects of two different doses of cranial irradiation on
growth and growth hormone (GH) release, we studied 61 children with acute
lymphocytic leukemia who had survived at least five years in continuous
complete remission. Forty-three children received 24 Gy (group 1) and 18
children received 18 Gy (group 2). Height was evaluated at diagnosis, at
the end of treatment, and 6, 12, and 24 months later. Growth hormone
release was evaluated by arginine and levodopa tests after the end of
treatment. After diagnosis, the height SD score decreased significantly in
both groups; two years after the end of treatment, only group 1 showed an
SD score for height that was still significantly lower than at diagnosis.
Group 1 showed impaired GH responses to the tests and, compared with
controls, group 1 in fact included a percentage of subjects with a normal
response to levodopa (ie, greater than 8 micrograms/L) that was
significantly lower (56.4% vs 83.3%) and a percentage of nonresponders to
both tests that was significantly higher (21.6% vs 0%). These data indicate
that only patients treated with lower cranial irradiation dosage (18 Gy)
had complete growth recovery and normal GH responses to pharmacologic
tests.
