Neoadjuvant Immunotherapy for Resectable Dedifferentiated Liposarcoma: A National Cohort Analysis.

Background: Neoadjuvant immunotherapy (NIT) with checkpoint blockade has been increasingly studied for soft tissue sarcomas, however, survival outcomes data are limited, and dedifferentiated liposarcoma (DDLPS) histology remains underrepresented in recent trial cohorts. We assessed the impact of NIT with or without radiation therapy (RT) on overall survival (OS) for resectable DDLPS.

Methods: The National Cancer Database (NCDB) was used to identify patients diagnosed with nonmetastatic DDLPS who received NIT and underwent surgical resection between 2016 and 2022. Primary outcome was 5-year OS.

Results: A total of 3414 patients with DDLPS met the inclusion criteria and NIT was administered to 31 (1%) patients. Factors associated with receipt of NIT were receipt of neoadjuvant RT (NRT, odds ratio [OR]: 5.75, p < 0.001) and male sex (OR: 3.33, p = 0.036). NIT was associated with a hazard ratio (HR) for mortality of 0.89 (p = 0.786). No difference was found in 5-year OS in the overall cohort (NIT 72% vs. 61% no NIT, p = 0.320) or in the propensity-matched cohort (68% vs. 65%, p = 0.848). Subanalysis between NIT with NRT versus NRT-only also did not find any significant difference in 5-year OS (88% vs. 59%, p = 0.331).

Conclusion: In this retrospective NCDB analysis of patients with resectable DDLPS, administration of NIT did not significantly affect OS.