Clinical features and prognosis of patients with soft tissue sarcoma in extremity and synchronous lung metastasis: A SEER analysis

Purpose: The aim of this study was to elucidate the relationship between clinical characteristics and risk of synchronous lung metastasis (SLM) in patients with extremity soft tissue sarcomas (ESTSLM) at the time of diagnosis and their prognosis. Methods Cases from 1975–2018 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database and demographic, treatments and survival outcomes were analysed. Results 533 of 7533 patients included in the analysis had SLM. Risk of lung metastasis was high with several variables including male gender, young age, white race, primary site in lower extremity or deep tissues, high differentiation grade, large tumor size, Ewing's sarcoma, rhabdomyosarcoma, and nodal metastasis. The 5 year cancer-specific survival (CSS) rate and median survival of ESTSLM patients was 22.4% and 14 months, respectively. Multivariate analysis showed that older adults, lack of primary site surgery and chemotherapy, and multi-site metastasis including the lungs, were risk factors (p < 0.05). Whereas chemotherapy improved short-term survival compared to survival without chemotherapy (2-year CSS rates of 36.2% vs 26.1%, p < 0.001), there were no survival benefits with metastasectomy (OS, p = 0.286; CSS, p = 0.627). Conclusions This is the first comprehensive study that unraveled lung risk factors and prognostic factors affecting metastasis in ESTSLM patients. The findings of this study may be useful for screening and management of patients with ESTSLM.