Retroperitoneal well-differentiated liposarcoma: prognostic significance of the degree of sclerosis in the tumor

Objective. To study the influence of the degree of sclerosis in the retroperitoneal well-differentiated liposarcomas (WDLPS) on the long-term results of surgical treatment of patients. Material and methods. The study included 111 patients with primary retroperitoneal WDLPS who underwent radical surgical treatment in Federal State Budgetary Institution «N.N. Blokhin National Medical Research Center of Oncology» of the Ministry of Health of the Russian Federation. Histological slides of all surgical specimens were reviewed by an experienced pathologist and reclassified according to WHO criteria (2013) for histological subtypes of the WDLPS. Patients were divided into groups depending on the degree of tumor sclerosis and enrolled in intergroup analysis of overall (OS) and recurrencefree (RFS) survival was performed. Results. OS is significantly worse in the group of patients who had the degree of sclerosis in the tumor >15% (p=0.0001; log-rank test). The median OS was 221 months (95% CI, 176, 265) in the group of lipoma-like subtype (sclerosis <15%), and 115 months (95% CI, 90, 140) in the group of sclerosing subtype (sclerosis >15%). The 10-year survival rates were 50% and 18% in the lipoma-like and sclerosing subtype groups respectively. RFS was also significantly worse in the group of patients with the sclerosing subtype of the WDLPS than in the group of patients with the lipoma-like subtype (p=0.001; log-rank test). The median RFS was 83 months (95% CI, 76, 90) in the lipoma-like subtype group, and 42 months (95% CI, 35, 49) in the sclerotic group. The 5-year RFS were 54% and 21% in the groups of lipoma-like and sclerosing subtypes respectively. Conclusion. Results of the study demonstrate that increased amount of sclerosing component in the WDLPS is associated with poor prognosis. 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.

liposarcoma, well-differentiated liposarcoma, histologic subtype, non-organ retroperitoneal tumor, prognosis, sclerosing

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