High incidence of vertebral fractures in children with acute lymphoblastic leukemia 12 months after the initiation of therapy

Abstract

Purpose: Vertebral fractures due to osteoporosis are a potential complication of childhood acute lymphoblastic leukemia (ALL). To date, the incidence of vertebral fractures during ALL treatment has not been reported.

Patient and methods: We prospectively evaluated 155 children with ALL during the first 12 months of leukemia therapy. Lateral thoracolumbar spine radiographs were obtained at baseline and 12 months. Vertebral bodies were assessed for incident vertebral fractures using the Genant semiquantitative method, and relevant clinical indices such as spine bone mineral density (BMD), back pain, and the presence of vertebral fractures at baseline were analyzed for association with incident vertebral fractures.

Results: Of the 155 children, 25 (16%; 95% CI, 11% to 23%) had a total of 61 incident vertebral fractures, of which 32 (52%) were moderate or severe. Thirteen (52%) of the 25 children with incident vertebral fractures also had fractures at baseline. Vertebral fractures at baseline increased the odds of an incident fracture at 12 months by an odds ratio of 7.3 (95% CI, 2.3 to 23.1; P = .001). In addition, for every one standard deviation reduction in spine BMD Z-score at baseline, there was 1.8-fold increased odds of incident vertebral fracture at 12 months (95% CI, 1.2 to 2.7; P = .006).

Conclusion: Children with ALL have a high incidence of vertebral fractures after 12 months of chemotherapy, and the presence of vertebral fractures and reductions in spine BMD Z-scores at baseline are highly associated clinical features.

Figure 1

Disposition of patients from baseline to 12 months with reasons for lack of available data on 33 children at 12 months.

Figure 2

Representative incident vertebral fractures at 12 months following initiation of therapy for pediatric ALL. (A) left panel shows a 9 year old girl at baseline with a normal spine radiograph. At 12 months (right panel), she has multiple incident vertebral fractures (a severe fracture at T5, moderate fractures at T10, T12 and L1, and mild fractures at T6, T7, T8 and T9). (B) left panel shows a 9 year old boy at baseline with a moderate L2 fracture. At 12 months (right panel), the L2 deformity has progressed to a severe fracture.

Figure 3

The median (with 25^th and 75^th percentiles) lumbar spine BMD Z-scores at baseline, 6 and 12 months post-initiation of therapy for children with and without incident vertebral fractures.

Figure 4

Results of logistic regression model 1 showing that the presence of at least one vertebral fracture at baseline was highly associated with increased odds of a child sustaining at least one incident vertebral fracture at 12 months. BMD, bone mineral density; GC, glucocorticoid; OR, odds ratio.