摘要Introduction:Patients with soft tissue sarcoma(STS)that present with metastasis at diagnosis have a dire prognosis.Within this patient population,we sought to assess:(1)demographic and clinical characteristics,(2)metastatic patterns,(3)treatment strategies,and(4)disease-specific survival(DSS).Materials and Methods:The SEER database was queried to identify patients with histologically confirmed STS of the pelvis or extremity.Univariate and multivariate analysis was performed using the Cox proportional hazards model.Disease-specific survival(DSS)was analyzed using the Kaplan-Meier method.Results:A total of 22,683 patients were retrieved,out of which 2,553(11.3%)had metastasis at diagnosis.Leiomyosarcoma,undifferentiated pleomorphic sarcoma(UPS),liposarcoma,synovial sarcoma,spindle cell sarcoma,and alveolar rhabdomyosarcoma(A-RMS)were the six most common STS presenting with metastasis.Among patients with metastasis,53.7%and 33.2%of patients had primary tumors located in the lower limb and pelvis,respectively.Lung was the most common site of metastasis in all subtypes except A-RMS,in which bone metastases and lymph node(LN)predominated(85.2%and 62.1%,respectively).Chemotherapy and radiotherapy were associated with higher DSS(HR = 0.788 and HR = 0.755,respectively).Five-year DSS was below 20%in all tumor histologies.Two-year DSS for patients with synchronous lung and liver metastases was 28%.Conclusion:Although the lung was the most common site of metastasis,metastatic patterns are highly variable depending on tumor histology.Metastatic A-RMS is most commonly presented with regional LN and bone involvement.Disease-specific survival remained poor for patients with metastatic disease at presentation regardless of(neo)-adjuvant radiotherapy or chemotherapy.