Clinicopathologic Characteristics and Clinical Outcome of Localized Liposarcoma: A Single-Center Experience over 25 Years and Evaluation of PD-L1 Expression

Purpose For liposarcoma (LPS), clinical course and proper treatment strategies have not been well-established. Recently, immune-checkpoint inhibitors have shown potential efficacy in LPS. We aimed to describe the clinical course of LPS and evaluate the clinical impact of programmed death-ligand 1 (PD-L1).Materials and Methods We reviewed all consecutive patients (n=332) who underwent curative-intent surgery for localized LPS at Asan Medical Center between 1989 and 2017. PD-L1 testing was performed in well-differentiated and dedifferentiated LPS.Results The median age was 56 years with males comprising 60.8%. Abdomen-pelvis (47.6%) and well-differentiated (37.7%) were the most frequent primary site and histologic subtype, respectively. During a median follow-up of 81.2 months, recurrence was observed in 135 (40.7%), and 86.7% (117/135) were loco-regional. Well-differentiated subtype (hazard ratio [HR], 0.38), abdomen-pelvis origin (HR, 2.43), tumor size larger than 5 cm (HR, 1.83), positive resection margin (HR, 2.58), and postoperative radiotherapy (HR, 0.36) were significantly related with recurrence-free survival as well as visceral involvement (HR, 1.84) and multifocality (HR, 3.79) in abdomen-pelvis LPS. PD-L1 was positive in 31.5% (23/73) and 51.3% (39/76) of well-differentiated and dedifferentiated LPS, respectively, but had no impact on survival outcomes.Conclusion Clinical course of LPS was heterogeneous according to histology and anatomic location. Clear resection margin was important to lower recurrence and postoperative radiotherapy might have additional benefit. A decent portion of well-differentiated and dedifferentiated LPS were positive for PD-L1, but its prognostic role was unclear. Further research is needed to determine clinical implications of PD-L1, especially for advanced-stage LPS with unmet needs for effective systemic treatment.