Somatic Leiomyosarcoma of the Soft Tissues: A Single-Institutional Analysis of Factors Predictive of Survival in 164 Patients.

Background: Somatic leiomyosarcoma (LMS) is an aggressive soft tissue sarcoma entity with a high metastatic potential. The purpose of this study was to identify prognostic indicators of survival in patients with somatic LMS of the soft tissues.

Methods: We retrospectively assessed the relationship between local recurrence-free survival (LRFS), disease-specific survival (DSS), overall survival (OS) and potential prognostic factors in 164 patients who were suitable for surgical treatment in curative intent. Patients with soft tissue LMS of the extremities, the truncal wall and the head and neck area were included. The median follow-up time was 4.9 years.

Results: In the entire cohort, the 5-year estimate of the DSS, OS and LRFS rate were 74.5% (95% confidence interval [CI] 65.0-81.8), 70.6% (95% CI: 60.9-78.3) and 63.4% (95% CI 53.4-71.9), respectively. Thirty-eight patients (23.2%) developed distant metastases with a median survival time of 1.5 years after diagnosis of metastasis. Surgical margins attained at the initial oncologic resection and eventual re-excisions did not influence DSS, OS and LRFS significantly. Within the R0 subgroup, close and wide negative margins led to similar outcomes. High histologic grade (P < 0.001), size >5 cm (P = 0.002) and subfascial localisation (P = 0.002) were associated with significantly diminished DSS in univariate analysis. In multivariate analysis, only histologic grade was found to be an independent prognostic factor of DSS.

Conclusions: The data from this study could not determine a prognostic significance of surgical margins suggesting that tumour characteristics other than margin status are important. Tumour biology reflected by the histologic grade dictates the final outcome.