Differential outcome of females with uterine versus extra-uterine leiomyosarcomas, a retrospective analysis.

Abstract

e23557 Background: Leiomyosarcomas, are aggressive sarcomas with survival rates among the lowest of all soft tissue sarcomas. Patients with uterine leiomyosarcoma (ULMS) have worse overall survival (OS) than those with extra-uterine leiomyosarcoma (EULMS). The effect of several clinical factors on OS have been investigated, including age, tumor size, grade, stage, and use of chemotherapy. Looking at the epigenetics of the 2 diseases, differentially methylated regions (DMRs) were statistically significant between the 2 groups. Methods: The 2004-2016 National Cancer Database was queried for females with ULMS and EULMS. We investigated several factors as predictors of binary survival status (alive or dead): patient’s age, race, year at diagnosis, tumor grade, size and stage, receipt of surgical treatment, chemotherapy, palliative care, surgical margins and time to treatment in days. Univariate and backward stepwise multivariate logistic regression models were used to determine prognostic factors associated with survival in each group. Kaplan-Meier (KM) method with log-rank test was used to compare OS rates between the 2 groups. All analyses were conducted using Stata/SE 15.1. Results: The total number of subjects was 16883. The median OS was 36.7 months in ULMS vs 57.2 in EULMS (P < 0.001). Older age was associated with a lower likelihood of survival in both groups (OR = 0.95, P = 0.018 in ULMS; OR = 0.97, P < 0.001 in EULMS). Lymphovascular invasion and receipt of palliative care were associated with a relatively large decrease in survival in ULMS only (OR = 0.25, P < 0.001; OR = 0.13, P = 0.015 respectively). In the EULMS group, increased likelihood of survival was associated with later years of diagnosis (OR = 1.27; P < 0.001). Larger tumor size (OR = 0.39; P = 0.001), stages II-IV or unstageable disease (OR = 0.56; P < 0.001), positive surgical margins or margins that were unevaluable (OR = 0.87; P = 0.009) and receipt of systemic therapy (OR = 0.85; P = 0.016) were associated with a lower likelihood of survival. Conclusions: Our study reiterated that females with ULMS had worse OS than those with EULMS. this difference can be attributed to certain clinical risk factors, however, it may also be secondary to genetic and epigenetic factors. Surprisingly, the use of palliative care in this study was associated with poorer OS in the EULMS group. Further studies are needed to investigate the genetic map of these diseases and highlight certain potentially targetable prognostic and predictive factors. Study limitations: Our study did not stratify ULMS and EULMS according to the stage to examine if the aforementioned factors would still be relevant in the limited versus metastatic setting.