Prognostic influence of the treatment approach for pulmonary metastasis in patients with soft tissue sarcoma

Soft tissue sarcomas (STSs) are rare heterogeneous malignancies of mesenchymal origin. Pulmonary metastases develop in approximately 50% of the patients with high-grade STS, being the major cause of mortality in patients with metastatic STS. Pulmonary metastasectomy has been reported to contribute to long-term survival; however, an appropriate treatment has not been established. We aimed to identify factors associated with post-metastasis survival in STS patients with pulmonary metastasis and determine the appropriate treatment for each patient. We retrospectively reviewed the records of metastatic STS patients treated between 2000 and 2017 and analyzed the clinico-pathologic variables to identify factors associated with the survival. The median survival after pulmonary metastasis was 20.6 months, and the 1-, 3-, and 5-year survival rates were 68.6%, 36.0%, and 25.1%, respectively. The survival was significantly greater in patients who underwent pulmonary metastasectomy than in those without surgery (38.9 months vs. 10.5 months; p < 0.0001). Among those who did not undergo surgery, the survival was significantly greater in patients who received chemotherapy than in those without chemotherapy (19.1 months vs. 6.3 months, p = 0.037). Multivariate analysis identified pulmonary metastasectomy as the most important prognostic factor for post-metastasis survival (Hazard ratio 5.623; 95% Confidence Interval 2.733-11.572; p < 0.0001). In conclusion, pulmonary metastasectomy was the most important prognostic factor for post-metastasis survival in patients with metastatic STS. In addition, chemotherapy could prolong survival in patients who were not eligible for pulmonary resection. Although we should carefully weigh the risks and benefits, appropriate treatment for pulmonary metastases could contribute to long-time survival.