ObjectiveThe aim of our study was to evaluate and compare the differences in the clinicopathological variables and overall survival (OS) of synchronous primary cancers of the endometrium and ovary (SCEO) and endometrial cancer with ovarian metastasis (ECOM). In addition, we aimed to determine the characteristics of and effective treatments for patients with SCEO to avoid misdiagnosis and overtreatment.Materials and methodsA review of medical records from January 2009 to January 2017 revealed 111 patients with coexisting ovarian and endometrial carcinoma diagnosed at the Obstetrics and Gynecology Hospital of Fudan University. Clinicopathological variables were analysed using the Chi square test and Student’s t test. The survival rate was estimated using the Kaplan-Meier method, and statistical significance was analysed using the logarithmic rank test (univariate analysis).ResultsThere were 51 cases of SCEO and 60 cases of ECOM. The mean age at diagnosis was 53.96 years and 55.41 years, respectively. There were no differences in age, menopausal status, BMI, CA125 level or complaints between the two groups. The 5-year survival rates were 58.8 and 36.7%, respectively (P < 0.001). Significant differences were found in the endometrial tumour classification, ovarian cancer stage, and lymph node and omentum metastasis between SCEO and ECOM.ConclusionsThe differences found between SCEO and ECOM are of great clinical significance. Our results reveal useful prognostic and clinicopathological features. More aggressive therapies should be administered to both SCEO and ECOM patients, especially elderly patients and those with menopause, endometrial tumours, advanced omentum metastasis, and lymph node dissection.