The influence of primary site on outcomes in leiomyosarcoma: a review of clinicopathologic differences between uterine and extrauterine disease.

Background: Leiomyosarcomas (LMS) comprise 25% of soft tissue sarcomas. Recent reports suggest differences in treatment outcomes between uterine (uLMS) and extrauterine (eLMS) disease that may reflect distinct disease biologies. We sought to identify prognostic factors in LMS and clinicopathologic differences between uLMS and eLMS. Methods: This is a single-center retrospective study evaluating 97 eligible patients treated for LMS between 2002 and 2010. Results: Median follow-up was 21.2 months. uLMS affected 53% of patients, and was less common beyond age 60 years compared with eLMS (10% vs. 37%, P = 0.002). Seventy-two percent of patients presented with nonmetastatic disease. Of these, 94% underwent curative surgery, among whom more uLMS patients achieved negative surgical margins (90% vs. 45%, P = 0.003). There were no significant differences in adjuvant therapy use and relapse patterns between uLMS and eLMS. Half of metastatic patients received palliative chemotherapy, among whom 76% received anthracycline-based chemotherapy in first line to which response rate was 31%. Median overall survival was 45.2 months, 49.8 months in uLMS, and 40.5 months in eLMS (P = 0.294). Among patients without metastases, median survival was 60.8 months (77.3 vs. 48.1 mo in uLMS and eLMS, respectively, P = 0.194). In metastatic disease, median survival was 20.7 months (22.0 vs. 17.5 mo in uLMS and eLMS, respectively, P = 0.936). Advanced disease stage, bone metastases and lack of metastasectomy prognosticated for inferior survival. Conclusions: While demonstrating interesting clinicopathologic differences, the evidence for uLMS and eLMS being biologically distinct remains inconclusive. Disease stage is prognostically most important in LMS.