AbstractObjectiveTo evaluate a psychometric validation of the endometrial cancer subscales (EnCS) in the Functional Assessment of Cancer Therapy‐Endometrial (FACT‐EN) among patients with endometrial cancer.MethodsThis cross‐sectional study was conducted at a tertiary university‐based hospital in South Korea between April and October 2022. Participants completed a survey questionnaire that included the FACT‐EN. Exploratory and confirmatory factor analyses (EFA, CFA) and the reliability were measured using the intraclass correlation coefficient (ICC) under a two‐way mixed model. Pearson's correlations were used to evaluate the validity. We also tested known‐group validity.ResultsIn total, 240 patients with endometrial cancer participated in the survey. In EFA, we found EnCS included four domains. In CFA, four‐factor solution model was good: CFI = 0.659; SRMR = 0.066, and RMSEA = 0.073. The mean (SD) of total score of FACT‐EN was 122.84 (23.58). The floor and ceiling effects were 0.4% and 0.4%, respectively. Cronbach's α coefficients for the five scales of the EnCS ranged from 0.78 to 0.91. The ICC of EnCS was 0.76. The convergent and discriminant validity of EnCS was acceptable. In the group analysis, older age and lower ECOG performance scores were associated with higher EnCS scores. The stomach and vaginal domains in EnCS were higher in patients who had completed treatment for more than 1 year compared to those who were still undergoing treatment.ConclusionsFACT‐EN has demonstrated its validity as an assessment tool with significant implications for capturing various symptoms in patients with endometrial cancer.