Epidemiology of undifferentiated sarcomas: A rare entity.

person Hassan Ali Mercy Catholic Medical Center, Darby, PA info_outline Hassan Ali, Sivaguha Yadunath Prabhakaran, Hafiz Muhammad Ajmal Saleem, Rajesh Thirumaran, Krishna Desai

Authors person Hassan Ali Mercy Catholic Medical Center, Darby, PA info_outline Hassan Ali, Sivaguha Yadunath Prabhakaran, Hafiz Muhammad Ajmal Saleem, Rajesh Thirumaran, Krishna Desai Organizations Mercy Catholic Medical Center, Darby, PA Abstract Disclosures Research Funding No funding sources reported Background: Undifferentiated Sarcomas (USar), previously known as malignant fibrous histiocytomas, are a group of rare and diverse malignant tumors of mesenchymal origin with a prevalence of 0.08-1 per 100,000. These are aggressive tumors with often high-grade morphology. The diagnosis is made by exclusion of other sarcoma entities upon bone marrow biopsy (criteria listed below). Undifferentiated sarcomas are of four major types, i.e. Pleomorphic, Epithelioid, spindle and round cells. The exact etiology of these sarcomas remains obscure, although many signaling pathways with various genetic alterations may be implicated in their development. The goal of this epidemiologic study is to assist in better understanding of this lesser known aggressive malignancy. Methods: The data was collected from Surveillance, Epidemiology and End Result database Research Plus Data, 17 Registries, Nov 2022 Sub (2000-2020). We extracted undifferentiated sarcoma cases diagnosed between 0-90 years of age, using the ICD Code 8805/3. The analysis was stratified age, gender, race, & primary site labeled. The analysis was further completed by comparing survival using the Log-rank test (GraphPad Prism). Results: A total of 1680 cases of USar were identified, which were diagnosed between 2000 and 2020. Median age of diagnosis was 59.5 years. 50.54% were males and 49.46% were females. Of these cases, ~64.05% were Caucasians, ~15.18% Hispanics, ~10.48% Asians or Pacific Islanders, ~9.35% Black, and < 1% were Alaskan natives/American Indian and Non-Hispanics of unknown race. Further survival curves were compared based on gender, race and organ system. The average months of survival (MoS) based on gender showed no statistical significance (p value 0.6077). MoS calculated for Whites (28), Blacks (16), Asian & Pacific islanders (1), Alaskan natives & American-Indians (15), & Hispanics (21) (p value < 0.0001). MoS based on involved organ system were compared for: head/face/neck (18), GI tract (10), respiratory tract (4), heart/mediastinum/pleura (9), skin & soft tissue (51), bone (32), breast (30), GU (19), CNS (26), gynecological tract (12) and male reproductive system (29) (p < 0.0001). Conclusions: Undifferentiated Sarcoma accounts for less than 1% of all adult tumors. Only 1680 cases were found in the past twenty years, rendering it one of the rarest seen malignancies. Of the reported data, USar was most commonly observed in Caucasians. Comparing the survival curves also showed that there was no difference in survival based on gender. The highest MoS was seen in undifferentiated sarcomas of skin and soft tissues while respiratory tract tumors had the lowest average survival time. More research and analysis is warranted to understand this lesser known malignancy given its extremely low incidence.