Descriptive Analysis of Epidemiology, Demographic Characteristics, and Survival of Dedifferentiated Liposarcoma in France

This is the authors' abstract. We don't add key points for this paper.

Dedifferentiated liposarcoma (DDLPS) is a rare soft tissue sarcoma with limited real-world epidemiologic data. This nationwide retrospective study describes the epidemiology, management, and outcomes of DDLPS in France using the NETSARC+ national sarcoma registry. A total of 1451 adults with histologically confirmed DDLPS diagnosed between 2010 and 2021 across 14 expert centers were included. The median age at diagnosis was 67 years, with a male predominance (M/F ratio 1.84). The retroperitoneum was the most frequent site (51.6%), and tumors were large (median 150 mm) and FNCLCC Grade 2-3 in 82.6%. MDM2 amplification was confirmed in 97.4% of tested cases. Surgery was performed in 91% of localized cases and was the strongest independent prognostic factor for overall survival (OS). After a median follow-up of 78.4 months, median OS was 90.3 months (95% CI 82.7-101.0). Among metastatic patients, the median first-line progression-free survival (PFS1) was 4.1 months, and second-line PFS (PFS2) was 3.1 months, with stable disease as the most common best response (40.6%) and 12% of partial response. Doxorubicin-based chemotherapy remained the predominant systemic treatment but yielded only modest activity, with no difference compared to other regimens in terms of response rate. Independent predictors of improved OS included younger age, smaller tumor size, good performance status, lower grade and absence of metastasis at diagnosis. This large, population-based study provides the most comprehensive real-world characterization of DDLPS in France, validating known prognostic factors, emphasizing the central role of surgery, and underscoring the persistent and unmet need for more effective systemic therapies.