Bone Metastases in Patients with Leiomyosarcoma: A Retrospective Analysis of Survival and Surgical Management

Background. Leiomyosarcomas (LMS) are malignancies with smooth muscle differentiation. Metastasis to the bone is not uncommon. The literature on the clinical course and management of such metastases is limited. Our study describes the clinical course of LMS to the bone, including survival rates, prognostic factors, and surgical management. Methods. We retrospectively reviewed 396 LMS patients presenting at an academic center between 1995 and 2020. We included LMS patients diagnosed with bone metastases and excluded patients with primary LMS of bone. We evaluated survival time with the Kaplan-Meier survival method and used Cox's proportional hazards regression analysis to determine factors associated with survival. Results. Forty-five patients with LMS (11%) had bone metastases. The most common LMS subtypes with bone metastases were uterine (N = 18, 40%) and retroperitoneal (N = 15, 33%). Bone metastasis was not an independent predictor of mortality by Cox regression analysis (HR 1.0, 95% CI: 0.67-1.5). Patients more frequently metastasized to the axial (N = 29, 64%) than to the appendicular (N = 5, 11%) skeleton. Bone was the first site of metastasis in 13 patients (29%). Patients presented with bone metastases at a median of 32.7 months (IQR: 5.2, 62.6) after initial LMS diagnosis. Twelve patients (27%) sustained a pathologic fracture. Twenty (44%) required surgical management, with 30 surgeries total. Three (15%) had a failure of reconstructive constructs. The median overall survival time was 69.7 months (IQR: 43.2, 124.5). There were no associations between the LMS subtype and survival. Pathologic fracture was an independent predictor of mortality by Cox regression analysis (HR 5.4, 95% CI: 1.8-16). Conclusion. The majority of patients with metastatic LMS to bone survive greater than 5 years and frequently require surgical intervention. Extended survival in this patient population should inform fixation and implant choice. No anatomic subtype was associated with risk for bone metastases. Pathologic fracture was associated with worse survival.