Vertebral fractures common among children with ALL
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More than 25% of children diagnosed with acute lymphoblastic leukemia, or ALL, develop vertebral fractures within 4 years of their diagnosis, and the highest risk is at 12 months, according to recent study findings published in The Journal of Clinical Endocrinology & Metabolism.
“A number of questions about the longer-term natural history and clinical predictors of [vertebral fractures] in pediatric ALL remain unanswered,” the researchers wrote. “For example, it is unknown whether incident [vertebral fractures] occur beyond the first 12 months of chemotherapy, and at what time point [vertebral fracture] risk is highest. Questions also remain about the severity of long-term bone morbidity due to [vertebral fractures], and the risk factors for incident [vertebral fractures] in the years following diagnosis.”
Leanne Ward, MD, FRCPC, of the Children’s Hospital of Eastern Ontario, and colleagues evaluated 186 children (median age, 5.3 years; 58% boys) with ALL to determine the incidence and predictors of vertebral fractures in the 4 years after diagnosis. Within 30 days of chemotherapy initiation, patients had a baseline bone health assessment.
Leanne Ward
Overall, there were 105 incident vertebral fractures (76 thoracic; 29 lumbar) among 38 patients within the 4 years after diagnosis of ALL. The incident rate was 8.7 per 100 person-years, with a 4-year cumulative incidence of 26.4%.
At baseline, 29 patients had incident vertebral fractures, and 65% of them had incident vertebral fractures in the subsequent 4 years. Eighty-two percent of 50 patients had their first vertebral fracture at baseline or 12 months, and 88% of 50 patients had their first vertebral fracture within 24 months.
Fifty percent of patients with incident vertebral fractures had moderate or severe fracture, and 39% of patients with incident vertebral fractures were asymptomatic.
In the first 6 months, the daily dose of glucocorticoid was high (mean, 14.2 ± 5.2 mg/m2 for boys; mean, 12.4 ± 4.3 mg/m2 for girls); doses decreased by 12 months (mean, 8.5 ± 5.4 mg/m2 for boys; mean, 8.5 ± 4.4 mg/m2 for girls). Compared with the healthy average, baseline lumbar spine bone mineral density z scores were low. Of patients with lumbar spine BMD z scores less than –2, 63% had incident vertebral fractures over 4 years, and of those with scores less than –1, 95% had incident vertebral fractures. After baseline assessment, lumbar spine BMD z scores increased.
There was a 5.9-fold increased vertebral fracture risk for every 10 mg/m2 in average daily glucocorticoid dose (P < .01).
Other predictors identified by the researchers for incident vertebral fractures risk were vertebral fractures at diagnosis, younger age and lower lumbar spine BMD z scores at baseline and each annual assessment.
“We have shown the proportion of children with incident [vertebral fractures] in the 4 years following ALL diagnosis is 26.4%, that most of the incident [vertebral fracture] burden is in the first year ... and that discrete clinical predictors are evident around the time of diagnosis ... and during chemotherapy,” the researchers wrote. “These natural history observations provide important data to support further study of the impact of including a spine radiograph as part of the routine bone health assessment in at-risk children with ALL.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.