Osteonecrosis:: an emerging complication of intensive chemotherapy for childhood acute lymphoblastic leukemia

Background and Objectives: Osteonecrosis (ON) is a potentially disabling complication of combination chemotherapy including high doses of steroids. The incidence and main risk factors for symptomatic ON have been investigated in a large group of children treated with high-dose steroids, prednisone and dexamethasone for children acute lymphoblastic leukemia (ALL). Design and Methods. From May 1995 to December 1999, 1421 patients <18 years old, with newly diagnosed non-B ALL, were registered in the AIEOP-ALL 95 study. Their data were reviewed to identify patients who developed symptomatic ON. For those who were positively identified additional data were requested concerning ON-related symptoms, treatment and outcome. Results. Overall, 15 of the 1421 patients developed symptomatic ON (1.1%) in a total of 29 sites. The estimated 5-year cumulative risk for clinically diagnosed ON was 1.6% (SE 0.4). The incidence was significantly higher among females (p=0.01) and older patients, with a peak rate of 7.4% (2.3) among those aged 10 to 17 years (p<0.0001). When the two factors, i.e. age and gender were combined, there was a striking increase in the risk among female patients aged 10 to 17 years. The median time between the diagnosis of ALL and that of ON was 17 months (range 8-45). The hip was the most frequently involved (19/29) site. Interpretation and Conclusions. Symptomatic ON occurred in only 1.1% of patients treated with BFM-type, intensive chemotherapy for childhood ALL. Female adolescents appear to be the subset of patients with the highest risk of ON, especially when categorized as having high risk leukemia and thus administered higher cumulative doses of dexamethasone.