PurposeThe aim of this study was to compare the clinical characteristics and outcomes of the cases with uterine high-grade endometrioid adenocarcinoma (HGEAC) and uterine carcinosarcoma (UCS).MethodsA total of 141 patients were included in this study. Of them, 61 cases had uterine HGEAC (group 1) and 80 had UCS (group 2). Both groups were compared in terms of clinical and pathological characteristics including age, stage, initial symptom, surgical approach, myometrial invasion, lymphovascular space invasion (LVSI), lymph node invasion, adjuvant therapy, and survival. The Kaplan-Meier and Cox proportional hazards models were used to compare the outcomes and prognostic factors.ResultsThere were no statistically significant differences between the groups with regard to age, nulliparity, menopausal status, and the main initial symptom. Both groups were similar in terms of stage, depth of myometrial invasion, and lymph node metastasis. Lymphadenectomy was performed in 74% and 91% of the cases in group 1 and group 2, respectively (p<0.001). LVSI was found to be more frequent in group 1 (p=0.032); however, in group 2, positive cytology was more common (p=0.008). Chemotherapy was the main adjuvant therapy for UCS, while radiotherapy was the main adjuvant therapy for HGEAC. There was no difference between the groups in terms of disease-free survival (DFS); however, overall survival (OS) was found to be longer in group 1 (p=0.029). Histopathologic type and LVSI were determined as independent predictive factors for OS.ConclusionUCSs are clinically more aggressive than HGEAC and should be considered as a separate group of tumors.