Invasive potential of retroperitoneal well-differentiated liposarcomas depending on the extent of sclerosing component in the tumor

Objective. To assess the influence of the extent of sclerosing component in the retroperitoneal well-differentiated liposarcoma (WDLPS) on the survival.

Material and methods. The retrospective study included 111 patients with primary retroperitoneal WLPS who underwent radical surgical treatment in Federal State Budgetary Institution «N.N. Blokhin National Medical Research Center of Oncology». Histological slides of all surgical specimens were reviewed by experienced pathologist and reclassified according to criteria of WHO (2013). Patients were divided into groups depending on the extent of the sclerosing component in the tumor and enrolled in intergroup analysis. We analyzed relationship between extent of the sclerosing component in the tumor and frequency of the pathologically confirmed visceral invasion. Also, we have analyzed the influence of the visceral invasion of WDLPS on the long-term results – overall (OS) and recurrence-free (RFS) survival.

Results. Pathologically confirmed visceral invasion was revealed in 17% of cases with the sclerosing component less 20%, and in 31% of cases with the sclerosing component more 20%. OS was significantly worse in the group of patients who suffered from WDLPS with visceral invasion than in the group of patients without visceral invasion (p = 0.009; logarithmic criterion). The median OS in the compared groups was 85 (95% CI, 84, 87) and 142 (95% CI, 109, 175) months, the 5-year OS rate was 41% and 86%, respectively. RFS was significantly worse in the group of patients with histologically confirmed visceral invasion than in the group without organ invasion (p = 0.001; logarithmic criterion). Median RFS in the compared groups was 26 (95% CI, 20, 32) and 57 (95% CI, 38, 76) months, 2-year RFS 33% and 85%, respectively.

Conclusion. Results of the study demonstrate more aggressive behavior of WDLPS with increasing extent of the sclerosing component. We believe that semi-quantitative counting of sclerosing component in retroperitoneal WDLPS can serve as an effective morphological marker of a less favorable prognosis of the disease.