Distinctive outcome in patients with non-uterine and uterine leiomyosarcoma

Background: Leiomyosarcomas represent the largest subtype of soft tissue sarcomas. Two subgroups can be distinguished, non-uterine (NULMS) and uterine leiomyosarcomas (ULMS). The aim of this retrospective study was to evaluate differences in clinical features and outcome between these two subgroups. Methods: Outcome and clinical-pathological parameters between 50 patients with NULMS and 45 patients with ULMS were assessed, and compared between both groups. Univariate and multivariable survival analyses were performed. Results: Patients with ULMS presented with larger tumors when compared to patients with NULMS (p < 0.001). More patients with ULMS initially presented with metastatic disease (67% vs. 36%, p = 0.007). Most common metastatic site was lung for both subtypes (28% and 38%). Five-year overall survival (OS) rates of 82.6% and 41.2% and median OS times of 92.6 (range: 79.7-105.4) and 50.4 (range: 34.8-66.0) months were observed in patients with NULMS and ULMS, respectively (p = 0.006). In multivariate analysis, initial metastatic disease remained an independent prognostic factor in terms of OS (p < 0.0001). Conclusion: At time of diagnosis ULMS were larger and more often metastasized. Therefore patients with ULMS showed unfavorable outcome when compared to NULMS. Later diagnosis might be caused by differences in symptoms and clinical presentation or a more aggressive biological tumor behavior.