Diagnostic Value of FAR, CAR, and PNI in Differentiating Benign From Malignant Endometrial Lesions and Assessing High-Risk Pathological Features

AIM: Benign endometrial lesions and endometrial cancer often overlap in clinical and ultrasonographic features. This study evaluated the ability of the fibrinogen-to-albumin ratio (FAR), C-reactive protein-to-albumin ratio (CAR), and prognostic nutritional index (PNI) to differentiate benign endometrial lesions from endometrial cancer and examined their associations with high-risk pathological features.METHODS: This retrospective case-control study included 374 patients with histopathologically confirmed endometrial lesions, comprising 250 benign lesions and 124 endometrial cancers. Receiver operating characteristic (ROC) curves were used to assess discrimination, and a clinical ultrasound model was constructed. PNI, CAR, and FAR were separately added to the model, followed by bootstrap internal validation. Associations with high-risk pathological features were evaluated using Firth logistic regression adjusted for age, body mass index (BMI), and histologic type.RESULTS: Patients with endometrial cancer had lower PNI and higher CAR and FAR levels. The areas under the curve (AUCs) for FAR, PNI, and CAR were 0.820, 0.793, and 0.781, respectively. The clinical ultrasound model had an AUC of 0.863, which increased to 0.918 after adding FAR and remained 0.903 after bootstrap correction. After correction for multiple comparisons, lower PNI and higher FAR were associated with deep myometrial invasion, lymphovascular space invasion, International Federation of Gynecology and Obstetrics stage III–IV, and grade 3 tumors, whereas CAR showed no statistically significant associations.CONCLUSIONS: FAR showed the highest observed discriminatory performance among PNI and CAR and provided incremental information beyond the clinical ultrasound model. Prospective multicenter validation is warranted.