Abstract
e23527 Background: Mixed Liposarcoma (LS) is an extremely rare subtype of LS, with characteristics often spanning 2 or more of the other LS subtypes such as myxoid, round cell, or well-differentiated LS. To date, the cytologic features of this uncommon tumor has yet to be described. Analyzing trends in diagnoses may produce valuable information about its epidemiology. The National Cancer Database (NCDB) was analyzed to uncover the demographic factors in patients diagnosed with mixed LS. Methods: A retrospective cohort study from 2004 to 2020 was conducted using the NCDB. 199 patients were found with a histologically confirmed diagnosis of mixed LS (ICD-8855-3). Race, gender, Hispanic origin, type of treatment facility, insurance coverage, and distance from patient residence to treatment facility were analyzed via descriptive statistics, and trends in incidence were interpreted using regression analysis. Results: The majority of patients were white (89%) and non-Hispanic (83%) with a relatively equal split of males (56%) and females (44%). The most common primary site of mixed LS was the retroperitoneum (72%), and the frequency of diagnosis decreased from 2004 to 2020 (R2 = 0.4568). Patients were treated at academic/research programs (45%), comprehensive community cancer programs (25%) and integrated network cancer programs (18%) that were generally located in the Middle Atlantic (19%), South Atlantic (18%), and East North Central (16%). The two primary payers at diagnosis include private insurance/managed care (45%) and Medicare (43%). Most patients were from counties in metro areas with a population of at least 1 million (57%) followed by metro counties with a population of 250,000 to 1 million (18%). The largest median household income quartile was $74,063 or more (38%), followed by $46,227 - $57,856 (22%). Most patients had a Charlson-Deyo Score of 0 (83%) with a NCDB analytic stage of either I (28%), III (26%), or not applicable (21%). Conclusions: To the best of our knowledge this NCDB analysis on mixed LS is the first of its kind and therefore addresses a significant knowledge gap. Most patients tend to be white and non-Hispanic. Mixed LS most commonly is found in the retroperitoneum, which is similar to case reports. We found that mixed LS patients have a relatively high household income, most often live in high populated metro areas, and are most frequently treated at academic/research programs. These findings are significant because these socioeconomic factors have not been noted before in literature. Further examination of these demographic and socioeconomic factors is required to understand how they impact treatment, diagnosis of, and survival of patients with mixed LS.