Survival Outcome and Prognostic Factors after Pulmonary Metastasectomy in Sarcoma Patients: A 18-Year Experience at a Single High-volume Referral Center

Background: Metastatic sarcoma patients have a poor prognosis with 3-year survival rate of 25%. About 30% of them present isolated lung metastases. We aimed to analyze the clinical outcome of sarcoma patients undergoing pulmonary metastasectomy (PM) and prognostic factors associated with local control, disease-free, and overall survival (OS). Patients and Methods: All sarcoma patients undergoing PM at Humanitas Cancer Center were retrospectively reviewed. Analyzed variables included clinicopathologic, surgical, and survival data. Exclusion criterion comprised a follow-up period inferior to 1 year. A univariable and multivariable Cox regression analysis was performed (P<0.05). Results: In total, 154 patients underwent PM from 1997 to 2015. Total complication rate was 7.1%. The median follow-up was 24 months. The median OS was 35.4 months from initial metastasectomy. In univariable analysis, we identified as significant negative prognostic factors a disease-free interval of <18 months, male sex, grading G3, and bilateral metastases. Three histology risk groups were defined according to OS: high risk (myxofibrosarcoma, malignant peripheral nerve sheath tumor, and Ewing sarcoma), intermediate risk (leiomyosarcoma, liposarcoma, and undifferentiated pleomorphic sarcoma), and low risk (synovial and chondrosarcoma) with a 3-year OS of 21.4%, 45.7%, and 74.1%, respectively. In multivariable analysis, male sex (P=0.042), bilateral metastases (P=0.004), and histology (intermediate vs. low-risk group, P=0.021; high vs. low-risk group, P<0.001) were identified as independent predictors of survival. Conclusions: PM for sarcoma is a valid therapeutic option. High-risk histologies and bilaterality of lung metastases are independent negative prognostic factors. A prognostic score to improve patient selection is proposed.