Background: Pleomorphic liposarcomas is an aggressive, high grade subtype of soft tissue sarcoma representing < 15% of liposarcomas. It most commonly arises in the retroperitoneum and proximal upper extremities. Current prognostic factors are centered around staging, which accounts for the grade, size, and location of the tumor in relation to the superficial fascia.
Methods: A total of 1778 patients diagnosed with pleomorphic liposarcoma were identified in the National Cancer Database and stratified by primary anatomical site: head/neck, upper limb, lower limb/hip, thorax/lung, pelvis, and retroperitoneum/abdomen. Kaplan-Meier survival tables were produced to estimate 1-, 5-, and 10-year overall survival. Log-rank tests with a Bonferroni correction for multiple comparisons and a multivariable Cox proportional hazards analysis were utilized to compare the primary site groups; P < 0.05 was considered significant.
Results: The most common primary anatomical site was the lower limb/hip. The head/neck primary anatomical site demonstrated the highest 10-year overall survival probability, while retroperitoneum/abdomen had the lowest (50% and 18.4%, respectively). Median survival was 9.19 years for the head/neck group, and 3.08 years for the retroperitoneum/abdomen group. Significant overall survival differences were found between the retroperitoneum/abdomen group and each of the following groups: head/neck ( P=0.001), upper limb ( P<0.001), lower limb/hip ( P<0.001), and pelvis ( P=0.001). After adjusting for age, biological sex, race and ethnicity, Charlson-Deyo comorbidity index, and AJCC pathologic stage, a 48.4% increased risk of death was found for retroperitoneum/abdomen vs. lower limb/hip primary site (95% CI: 14.6% to 92.1%; P=0.003). Thorax/lung vs. lower limb/hip was also associated with a 55.1% increased risk of death (95% CI: 8.4% to 121.9%; P=0.016).
Conclusion: The current prognostic modality for pleomorphic liposarcoma is limited. There are statistically significant differences in survival based on primary anatomical sites, which may serve as a useful prognostic indicator. Tumors manifesting in the retroperitoneum/abdomen demonstrated the lowest survival.
