Subtype-specific characteristics and outcomes of liposarcoma: A population-based study using Japan's National Cancer Registry.

Abstract

Liposarcoma demonstrates significant biological and clinical heterogeneity across subtypes, yet optimal treatment strategies remain controversial. We evaluated subtype-specific treatment outcomes and hospital volume effects using population-based registry data. We conducted a population-based cohort study analyzing 6,678 patients with liposarcoma diagnosed between 2016 and 2019 from the Japanese National Cancer Registry. Subtype-specific clinical characteristics, treatment patterns, and survival outcomes were evaluated using Cox regression and Kaplan-Meier methods. Propensity score matching was performed to assess radiotherapy and chemotherapy effectiveness while controlling for confounding variables. Well-differentiated liposarcoma was most common (46.2 %), followed by dedifferentiated (27.8 %), myxoid (10.8 %), and pleomorphic (3.2 %) subtypes. Myxoid liposarcomas predominantly affected patients aged <60 years (63.8 %). Multivariate analysis identified male sex (HR 1.264, p = 0.008), older age (HR 3.307, p < 0.001), retroperitoneal location (HR 1.861, p < 0.001), distant disease (HR 6.091, p < 0.001), and treatment at low-volume hospitals (HR 1.381, p = 0.001) as independent poor prognostic factors. Propensity score-matched analysis demonstrated improved survival with radiotherapy in dedifferentiated liposarcomas (3-year survival: 76.5 % vs. 66.1 %, p = 0.022) and with chemotherapy in pleomorphic liposarcomas (3-year survival: 87.5 % vs. 68.8 %, p = 0.038). Treatment efficacy varies significantly across liposarcoma subtypes, with potential survival benefits of radiotherapy in dedifferentiated subtypes and chemotherapy in pleomorphic subtypes. These findings support subtype-guided treatment approaches and suggest benefits of centralized care for optimal therapy implementation.