Clinical course and prognostic factors of patients with dedifferentiated liposarcoma: a retrospective analysis

IntroductionDedifferentiated liposarcoma (DDLPS) is a fairly common subtype of soft tissue sarcoma, but relatively little is known about the clinical course and prognostic factors of this mesenchymal malignancy.MethodsWe performed a retrospective analysis of patients diagnosed with DDLPS at the University Hospital Leuven, Belgium between 1991 and 2022 based on an established clinical database and patient records.ResultsWe identified 259 patients with DDLPS, with the retroperitoneum as most common location of the primary tumor (47.5%). 204/259 patients (78.8%) patients had primary surgery. Radiotherapy was administered in the pre- (46/259, 17.8%) or postoperative setting (51/259, 19.7%). At diagnosis 28/259 (10.8%) patients presented with locally inoperable disease and 26/259 (10.0%) with synchronous metastasis. In patients who had primary surgery, local relapses were seen in 114/259 (44.0%) patients and 80/259 (30.9%) patients developed metachronous metastasis. A total of 48/259 (18.5%) patients developed both local relapse and metastasis. Patients with inoperable or metastatic disease were often treated with systemic therapy. The most common first-line systemic therapies were doxorubicin (51/98, 52.0%), doxorubicin combined with ifosfamide (12/98, 12.2%) and different types of experimental treatments (18/98, 18.4%). The median overall survival from first diagnosis of DDLPS to death of all causes was 70.5 months (95% confidence interval [CI] 56.6-98.6) for all patients, 10.9 months (95% CI 3.6-29.2) in patients with inoperable disease, 28.4 months (95% CI 1.3-199.3) for patients with local relapse and only 9.4 months (95% CI 1.2-25.9) for patients with metastatic disease. We identified lower age, primary surgery, absence of synchronous metastasis, absence of local relapse and treatment with experimental therapy as statistically significant favorable prognostic factors.ConclusionsDDLPS is a subtype of soft tissue sarcoma with an aggressive clinical course and very poor prognosis, especially in patients with inoperable or metastatic disease. The results with classic chemotherapy are poor, and experimental treatments may be a preferred choice for individual patients. Data from this retrospective series can inform the design of future prospective and ongoing trials in this setting.