Purpose: Osteonecrosis (ON) is a potentially serious complication of therapy in survivors of childhood cancer. Our goals were to describe the incidence of ON and identify patient and treatment characteristics associated with elevated risk.
Patients and methods: The rate of self-reported ON was determined for 9,261 patients enrolled onto the Childhood Cancer Survivor Study, a cohort of 5-year survivors of childhood cancer diagnosed from 1970 to 1986, and compared with the rate in a random sample of 2,872 siblings of survivors. Survivors with positive responses were reinterviewed to confirm the diagnosis.
Results: Fifty-two cancer survivors reported ON in 78 joints, yielding 20-year cumulative incidence of 0.43% and a rate ratio (RR) of 6.2 (95% CI, 2.3 to 17.2) compared with siblings, adjusted for age and sex; 44% developed ON in a previous radiation field. The RR was greatest among survivors of stem-cell transplantation for acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), and chronic myelogenous leukemia (RR = 26.9, 66.5, and 93.1, respectively). Nontransplantation patients with ALL (RR = 6.5; 95% CI, 2.2 to 19.4), AML (RR = 11.2; 95% CI, 2.1 to 61.2), and bone sarcoma (RR = 7.3; 95% CI, 2.0 to 26.2) were at higher risk for ON. Older age at diagnosis, shorter elapsed time, older treatment era, exposure to dexamethasone (+/- prednisone), and gonadal and nongonadal radiation were independently associated with ON.
Conclusion: ON among long-term survivors of childhood cancer is rare. However, compared with siblings, childhood cancer survivors have a significantly increased relative rate of ON, particularly those who were older at diagnosis and who received dexamethasone or radiation therapy. Future studies are needed to better delineate our findings, particularly the increased risk after gonadal radiation.