Differences in recurrence and survival of extremity liposarcoma subtypes.

BACKGROUND: Liposarcomas can be divided into four subtypes and are most frequently located in the extremities. There are currently no studies comparing the clinical outcomes, such as local recurrence and distant metastasis, between the distinct subtypes of primary LPS of the extremity specifically.

METHODS: Retrospective databases of two expertise centres (Rotterdam-R, Warsaw-W) of patients with liposarcoma located in the extremities from 1985 to 2015 were used to analyse 5-year local recurrence-free survival (5y-LRFS), 5-year distant metastasis-free survival (5y-DMFS) and 5-year overall survival (5y-OS).

RESULTS: We identified 456 patients: 192 well-differentiated liposarcomas (WDLPS), 172 myxoid liposarcomas (MLPS), 54 pleomorphic liposarcomas (PLPS), 23 dedifferentiated liposarcomas (DDLPS) and 15 other subtypes. The frequency of (neo)adjuvant radiotherapy (R: 34.5% vs. W: 78.4%) and R0-resections (R: 41.0% vs. W: 84.1%) differed between the datasets. Local recurrences (LR) were observed most frequently in DDLPS (5y-LRFS 62.4%), followed by PLPS (71.4%), WDLPS (77.0%) and MLPS (84.5%, p = 0.054). Distant metastases (DM) were most commonly observed in PLPS (5y-DMFS 46.9%), followed by MLPS (74.0%), DDLPS (86.3%) and WDLPS (97.3%). 5y-OS was poorest in patients with PLPS (47.6%) and DDLPS (54.4%), followed by MLPS (79.7%) and WDLPS (92.4%, p < 0.001). Male gender significantly increased the risk of LR and DM. The subtypes MLPS and PLPS were significant prognostic factors for DM and OS. Additionally, DDLPS and age had significant impact on OS.

CONCLUSION: In the largest cohort of extremity LPS patients reported to date, LPS subtypes show distinct patterns of LR, DM and OS, stressing that 'extremity LPS' is not a single entity.