ESPE Abstracts

Background and Aim: Vertebral fractures (VF) in children with acute lymphoblastic leukemia (ALL) are often symptomatic and impairing life quality. Prevalence of children with VF at ALL diagnosis has been reported as 16% with peak incidence occurring during the first year after diagnosis and a 6-year cumulative incidence of 32.5%. Moreover, only 15.8% of these patients will have vertebral reshaping 24 months after ALL diagnosis. Additionally, 23% of ALL survivors will sustain vertebral deformities 15 years after diagnosis from whom 34% will report back pain in adulthood. Intravenous bisphosphonates (BP) can increase bone density and decrease bone pain. Our aim was to describe the bone health trajectory of a cohort of children with symptomatic VF treated with BP during their ALL treatment.

Methods: This retrospective cohort study included children treated with DFCI11-001 and DFCI16-001 protocols. As per institutional protocol, lateral spine X-rays and dual-energy X-absorptiometry scans were obtained within the first month of diagnosis, annually, and if new back pain occurred during the treatment period. Patients with symptomatic VF after induction treatment were treated with IV BP. VF were graded according to the Genant classification.

Results: 139 children (52% male) with a median age of 5.2 years (IQR 3.3-10.5 years) at diagnosis were included. Prevalence of patients with VF at ALL diagnosis was 10%. Sixteen patients with symptomatic VF after induction (total of 24 VF) were treated with BP for a median duration of 18 months (IQR 13.8-21). Among BP-treated patients, six (37.5%) presented VF at diagnosis while the remaining ten experienced their first VF within the 2^nd to 12^th month period after diagnosis. After BP initiation, patient-reported pain subsided in all children. One patient had an incident VF 6 months after BP initiation. One patient experienced a febrile acute phase reaction. At the end of ALL treatment, 46.7% of BP-treated patients had completely reshaped VF. Among those with persistent VF at 24 months of diagnosis (53,3%), 50% had improved Genant grading. Moreover, among BP-treated patients, children with fully reshaped VF had higher BMD Z-scores at the end of ALL treatment compared to patients with persistent VF (mean BMD Z-scores increase: 0.85 vs 0.73).

Conclusion: We report preliminary results from the first pilot study exploring VF trajectory in children with ALL treated with BP for symptomatic VF. Prospective trials are needed to confirm if BP influence VF reshaping in this population.