1629MO - First-line chemotherapy (CT) in advanced well-differentiated/dedifferentiated liposarcoma (WD/DD LPS): An EORTC Soft Tissue and Bone Sarcoma Group (STBSG) retrospective analysis

Background

WD/DD LPS usually arises in the abdomen, while other LPS subtypes mainly have an extra-abdominal origin. With the lack of prospective data on anthracycline-based CT in advanced WD/DD LPS, we conducted a retrospective analysis of the activity of cytotoxic regimens in patients (pts) with LPS of intrabdominal origin (IA-LPS) who had entered EORTC/STBSG clinical studies, assuming that the vast majority of LPS at this location are WD/DD LPS.

Methods

We searched for all adult pts treated with first-line CT for advanced IA-LPS in EORTC/STBSG phase II-III trials from 1970. Treatment was aggregated into 5 groups: anthracycline (A) alone (Doxorubicin (D) 75 mg/m², Caelyx 50 mg/m², Epirubicin 75 mg/m², Epirubicin 150 mg/m²), Ifosfamide (IFO) alone (IFO 5 g/m², IFO 9 g/m², IFO 12 g/m²), D+IFO (D 50 mg/m²+IFO 5 g/m², D 75 mg/m²⁺IFO 5 g/m², DOX 75 mg/m²+IFO 10 g/m²), D+cyclophosphamide+vincristine+DTIC (CYVADIC), “other” (brostallicin, trabectedin). Response was assessed by RECIST or WHO criteria. Progression-free survival (PFS) and overall survival (OS) were computed by Kaplan-Meier method.

Results

109 IA-LPS pts from 13 trials, enrolled between 1978 and 2012, were identified (median age 57 yrs). Overall, there were 10/109 (9.2%) responders to CT: Table: 1629MO

At 10-mo median follow-up (IQR 6-24), m-OS was 19 mos (95%CI 15-21), m-PFS 4 mos (95%CI 3-6). D+IFO achieved a not statistically significant longer m-PFS (12 mos) and m-OS (31 mos) than observed with other regimens. Univariate and multivariate analysis of response to CT did not identify prognostic factors.

Conclusions

Cytotoxic CT, in particular D alone, had limited activity in advanced IA-LPS. Though IFO-containing regimens showed higher activity compared to A alone in a small number of cases. This series provides a benchmark for future trials on new drugs in WD/DD LPS.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

EORTC Soft Tissue and Bone Sarcoma Group.

Funding

Has not received any funding.

Disclosure

S. Stacchiotti, B. Kasper: Honoraria (self), Research grant/Funding (institution), Travel/Accommodation/Expenses: Pharmamar. R. Sanfilippo: Research grant/Funding (institution), Travel/Accommodation/Expenses: Pharmamar. All other authors have declared no conflicts of interest.