Pathologic femur fractures after limb-sparing treatment of soft-tissue sarcomas

Introduction: Local control for sarcomas of the long bones includes limb sparing surgery and radiotherapy. While effective, there are potential complications. Methods: Patients treated for a soft tissue sarcoma of the thigh with limb-sparing surgery and radiation therapy between 1986 and 2000 at the University of Minnesota Masonic Cancer Center (n = 89) were identified. Demographic, tumor, and treatment characteristics were abstracted from the medical record. Univariate analysis was conducted to identify significant risk factors for fracture. Results: Survivors (58% male), median age of 50 (7-88) years, reported 8 (9%) fractures at a median of 7.3 (0.8-21.9) years from diagnosis after a median of 6300 (2000-7020) cGy of radiation. All fractures occurred within the previous radiation field, after no trauma. Three of the 8 (37.5%) had delayed union, 2 (25%) nonunion healing. Significant risk factors included periosteal stripping (p = 0.006), anterior compartment location (p = 0.022), and having 100% of the femoral circumference irradiated (p = 0.018). Taking into account time to fracture using Kaplan Meier and log rank tests, these same predictors were identified. Older age, female sex, use of chemotherapy, and timing of radiation were not predictive of femoral fracture. Conclusion: Anterior tumor location, periosteal stripping, and radiation to 100% of the femur circumference are associated with femoral fracture. These patients require long-term monitoring and may warrant prophylactic intramedullary pinning or other protective measures. Implications for Cancer Survivors: Survivors of soft tissue sarcomas of the femur may be at risk for the development of femur fractures and warrant close observation.