Multicenter retrospective study of osteonecrosis in pediatric ALL patients treated with the NOPHO ALL2008 protocol

A retrospective study at five tertiary centers in Finland described the radiological evolution of osteonecrosis (ON) lesions in pediatric ALL patients treated according to the NOPHO ALL2008 protocol. The study included 37 patients with 235 ON lesions. The mean age at ALL diagnosis was 10.6 years and the mean age at ON diagnosis was 11.9 years. The mean follow-up time from ON diagnosis was 3.3 years (range 0.04-13.5). During follow-up, 55% of lesions remained stable, 35% resolved, 8% improved to lower grade, and 2% progressed. Factors associated with unfavorable ON outcomes were female sex, older age at diagnosis, and hematopoietic stem cell transplantation. The authors conclude that ON remains a clinically significant, common adverse event of childhood ALL treatment.