Reductions in Bone Mineral Density are Apparent Early in Children with Prevalent Osteonecrosis Lesions Following Leukemia Therapy.

Osteonecrosis (ON) is a serious complication of childhood acute lymphoblastic leukemia. We determined the prevalence of osteonecrotic lesions in our patient population by a one-time multi-site magnetic resonance imaging (MRI) more than one year following leukemia therapy. MRI findings were evaluated in relationship to clinical factors (including longitudinal changes in bone mineral density [BMD]). Eighty-six children enrolled in the STeroid associated Osteoporosis in the Pediatric Population (STOPP) study were evaluated for ON at 3.1±1.3 years following therapy. Thirty children had a total of 150 confirmed ON lesions (34%). Lumbar spine (LS) BMD Z-scores (mean ± SD) were low at diagnosis and similar between patients with and without ON (-1.09±1.53 versus -1.27±1.25, p=0.549). LS BMD Z-scores declined from baseline to 12 months in children with ON (-0.31±1.02) but not in those without (0.13±0.82, p=0.035); the hip BMD Z-scores from baseline to 24 months declined in both groups, but to a greater extent in those with ON (-1.77±1.22) compared to those without (-1.03±1.07, p=0.045). At the time of the MRI, mean total hip and total body (TB) BMD Z-scores were lower in children with ON (hip -0.98±0.95 versus -0.28±1.06, p=0.010; TB -1.36±1.10 versus -0.48±1.50, p=0.018). Pain occurred in 11/30 (37%) with ON versus 20/56 (36%) without, p=0.841. In multi-variable models, older age at diagnosis (odds ratio [OR], 95% confidence interval [CI]) 1.57 [1.15, 2.13], p=0.004), and hip BMD Z-score at MRI (OR 2.23 [1.02, 4.87], p=0.046) were independently associated with ON. Overall, 1/3 of children demonstrated ON after leukemia therapy. Those with ON had greater reductions in spine and hip BMD Z-scores in the first one and two years of therapy, respectively. Older age and lower hip BMD Z-scores at MRI were significantly associated with prevalent, off-therapy ON. These data assist in identifying children at risk of ON. This article is protected by copyright. All rights reserved.