Risk Factors for Lymph Node Metastasis of Soft Tissue Sarcomas of the Head, Neck and Extremities, And the Clinical Significance of Negative Lymph Node Dissection

Abstract

Background: To determine the risk factors for lymph node metastasis (LNM) of soft tissue sarcomas (STS) of the head, neck, and extremities, and the clinical outcome of negative lymph node dissection (NLND). Methods: We pooled patients of STS using the Surveillance, Epidemiology, and End Results (SEER) database from 1988 to 2015. Logistics regression analysis to identify risk factors for LNM, the Cox proportional hazards model and Fine-Grey’s model were used for survival analysis, Propensity score matching analysis (PSM) was further used to clarify the impact of NLND on patient prognosis.Results: A total of 3,276 patients were enrolled in our study, of whom 283 (8.6%) developed LNM. Rhabdomyosarcoma had the highest rate of LNM (25.3%), followed by clear cell sarcoma (16.8%) and epithelioid sarcoma (12.4%), while leiomyosarcoma had the lowest rate of LNM (1.3%). Sex, tumor size, grade, histology, and site were significantly associated with LNM. Age, tumor size, grade, stage, histology, and marital status were independent prognostic factors for the cancer-specific survival for patients without LNM. For specific histologic subtypes of STS, NLND significantly improves overall survival (HR: 0.718, 95%CI, 0.535-0.962; P=0.026) and cancer-specific survival (HR: 0.699, 95%CI, 0.506-0.967; P=0.031) and reduces cancer-specific mortality (Gray’s test, P=0.017). However, for patients with leiomyosarcoma, NLND did not improve overall survival (P=0.46) or reduce cancer-specific mortality (Gray’s test, P=0.772).Conclusions: We identified the rate of LNM and risk factors for LNM in STS of the head, neck and extremities. In addition, prophylactic NLND treatment is necessary and has a clinical benefit for patients with STS who are at high risk for LNM, but has no significant impact on the prognosis of patients with leiomyosarcoma.