Risk factors for omental metastasis and the effect of omentectomy on survival in type 2 endometrial cancer patients

To investigate the risk factors for occult omental metastasis and the effect of omentectomy on the survival of type 2 endometrial cancer (EC) patients. This study enrolled patients who were diagnosed with high-risk (grade 3, serous, clear cell, undifferentiated, carcinosarcoma, or mixed type) EC between 2000 and 2021 and underwent surgery in our center. Data from 482 patients were analyzed retrospectively. Omentectomy was performed in 405 (84.0%) patients. Omental metastases were detected in 61 (12.7%) patients. Eighteen (29.5%) of these metastases were occult. Adnexal involvement, malignant cytology, and peritoneal spread were independent risk factors for omental metastasis. The 5-year overall survival (OS) rate was 59.5% in patients who underwent omentectomy and 64.7% in those who did not (P = 0.558). In patients with and without omental metastases, the overall 5-year OS rates were 34.9% and 63.5%, respectively (P < 0.001). The 5-year OS rates of patients with a normal omentum, gross tumors, and occult metastases were 63.5%, 26.9%, and 52.5%, respectively (P < 0.001). Omental metastases is not uncommon in type II endometrial cancer; approximately one third of patients have occult metastases. Factors - positive cytology, adnexal involvement, and peritoneal involvement are associated with higher probability of omental metastases.