Study Evaluates Bone Health in Children With Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia is the most common type of childhood cancer, and fractures from osteoporosis are an important cause of morbidity in patients with ALL. A recent study aimed to document the annual incidence and predictors of vertebral fractures (VF) and non-VF in order to determine whether they occur years after chemotherapy.

The study, published recently in the Journal of Bone and Mineral Research, enrolled patients through oncology clinics within 10 children’s hospitals in Canada from 2005 to 2007. The patients underwent a baseline assessment within 30 days of chemotherapy initiation and then prospective evaluation for 6 years, according to the study.

The researchers collected data on anthropometry, back pain, physical activity, calcium and vitamin D intake, glucocorticoid (GC) exposure, and methotrexate exposure every 3 months for the first 4 years. After 4 years, there were 2 annual study visits that included the same clinical information.

“Non-VF were classified as either long bone fractures (humerus, radius, ulna, femur, tibia, and fibula) or 'other fractures.' Low trauma was defined as falling from a standing height or less at no more than walking speed,” the researchers explained. “An incident VF was defined as a new fracture in a previously normal vertebral body or worsening of an existing VF (ie, an increase in the Genant grade) at any time during the observation period.”

A total of 186 children with ALL were enrolled in the study and 136 had a valid spine radiograph at 4 years. The study also said that between 4 and 6 years of follow-ups, 9 patients that had missing data were presented at follow-up visits, and 43 patients had missing data (29 withdrew consent, 12 were lost to follow-up, and 2 died). As a result, 92 patients at year 5 and 102 patients at year 6 had valid VF assessments.

The researchers found that 36% of children had fractures at any skeletal site over the 6-year period. Additionally, 71% of all incident fractures occurred within the first 2 years. Non-VF was found to have occurred in 1.6% at baseline, with peak annual incidences occurring at 2 years and 5 years. The incidence rate of VF was 11.9 per 100-person years, with a 6-year cumulative incidence of 32.5%.

"In revealing that vertebral fractures are frequent in children with ALL on chemotherapy, and that older children and those with more severe collapse are at risk for residual vertebral deformities, strategies to prevent vertebral fractures in those at greatest risk for permanent sequelae now merit further study," concluded lead author Leanne Ward, MD, of Pediatrics Children's Hospital of Eastern Ontario.

Reference

Ward LM, Ma J, Lang B, et al. Bone morbidity and recovery in children with acute lymphoblastic leukemia: results of a six-year prospective cohort study. [published online May 22, 2018]. J Bone Miner Res. Doi: 10.1002/jbmr.3447