Femur fractures after limb-sparing treatment of soft-tissue sarcomas: One institution's experience.

Abstract

e19601 Background: Local control for soft tissue sarcomas of the long bones often includes limb sparing surgery with the addition of radiation therapy. While effective, there are potential complications including poor wound healing and late-onset fractures. Methods: This analysis includes 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). Demographic, tumor, and treatment characteristics including age, sex, histology, location (anterior, posterior, medial, buttock, popliteal fossa), use of adjuvant chemotherapy (yes/no), use of periosteal stripping (yes/no), timing of radiation (pre-/post-operative, both), radiation dose [high (>60 Gy), low (</+60 Gy), radiation field length [> 30 centimeters (cm), </= 30 cm], circumference of radiation field (100%/< 100% of femur) were abstracted from the medical record. Univariate analysis was conducted to identify significant risk factors for fracture. Given the small numbers of patients with a femoral fracture, multivariate analysis was unable to be performed. Results: Survivors (58 % male) with a 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 minimal or 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 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. Conclusions: Anterior tumor location, the presence of periosteal stripping, and radiation to 100% of the femur circumference are significantly associated with femoral fracture. These patients require long-term monitoring and may warrant prophylactic intramedullary pinning or other protective measures. No significant financial relationships to disclose.