[Evaluation of prognostic factors for liposarcoma]

Objective: To investigate the relevant prognostic factors of liposarcoma (LPS). Methods: The data of 78 patients with LPS treated in our hospital from July 2009 to March 2017 were reviewed. The 78 patients included 41 males and 37 females, and the average age was (60.5 ±13.4) years (ranged from 18 to 85 years). Among the 78 LPS patients, 27 were well-differentiated LPS, 13 were myxoid LPS, 35 were dedifferentiated LPS and 3 were pleomorphic LPS.The distribution of lesion location included 40 cases of extremities and 38 cases of retroperitoneal. 21 cases were treated with radical excision, 57 cases were treated with marginal resection. 7 patients were treated with postoperative radiotherapy and 9 patients with postoperative chemotherapy. Progression free survival (PFS) and overall survival (OS) of LPS patients were analyzed as clinical outcomes. Prognostic factors were analyzed by univariate and multivariate analyses. Results: 43 patients had local recurrence (9 of extremities/ 34 of retroperitoneal), 18 patients with metastasis (4 of extremities/ 14 of retroperitoneal). The 5-year PFS rate was 31.4% and 5-year OS rate was 44.3%. Univariate analysis showed that the histological subtype and the tumor location were related with PFS (P<0.05), while the histological subtype, the tumor location, the tumor size, the recurrence and metastasis were related with OS (P<0.05). Multivariate cox regression analysis showed that the tumor location was the independent prognostic factor of PFS (P<0.05), while the histological subtype and metastasis were the independent prognostic factors of OS (P<0.05). The median PFS of patients with myxoid LPS treated with radiotherapy was 34.6 months, which was significantly longer than 28.3 months of myxoid LPS patients without radiotherapy (P<0.05). Conclusions: The tumor location is an independent prognostic factor of PFS in LPS patients.Retroperitoneal LPS is more prone to relapse and metastasize. OS is affected by pathological subtype and metastasis. Radiotherapy can improve the PFS of patients with myxoid LPS.