Background: Multimodal treatment regimens for Ewing's sarcoma have led to survival rates approaching 70% of patients with no metastases at diagnosis. However, these treatments have long-term side effects. Low bone mineral density (BMD) and risk of fractures can occur owing in part to chemotherapy and limited mobility from local control of the primary tumor.
Questions/purposes: We performed this study to answer the following questions: (1) Do long-term survivors of the Ewing family of tumors sustain low BMD? (2) Which factors are associated with BMD in these patients? (3) Do they experience fractures? (4) Are BMD and fractures associated with each other?
Methods: We queried our institutional registry to identify all known survivors of Ewing tumors who were treated before 2005. Of 100 such patients, 67 (67%) responded to a postal survey to participate in this study, and an additional 11 (11%) patients were excluded according to prespecified criteria. In the remaining 56 long-term survivors (27 females, 29 males; mean±SD age at followup, 32±10 years; mean followup, 15±7 years), BMD was measured by dual-energy x-ray absorptiometry and history of fractures was assessed using a questionnaire. Associations were tested using univariate and multivariate models by stepwise variable selection procedure, including Bonferroni correction.
Results: Thirty-one of 56 (56%) patients had a pathologic BMD. Seven (13%) had osteoporosis and 24 (43%) had osteopenia. Factors related to low BMD after Bonferroni correction were the length of time between surgery and followup and the BMI at followup. Twenty-one patients reported 29 fractures. With the numbers available, BMD levels were not associated with fractures.
Conclusions: We could not confirm some potentially important predictors for fractures to be associated with clinical events of interest. However, the data are valuable as hypothesis-generating pilot data for future, multicenter prospective studies. If BMD changes cannot explain the propensity of fractures, there may be other bone characteristics like microarchitectural changes of bone to more accurately explain the effect.
Level of evidence: Level IV, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.