An elevated preoperative serum calcium level is a significant predictor for positive peritoneal cytology in endometrial carcinoma

OBJECTIVE: To evaluate preoperative serum calcium concentration and investigate the association between calcium level and positive peritoneal cytology in endometrial carcinoma (EC). METHODS: A total of 510 patients who were diagnosed with EC and had surgery were initially enrolled in this study at Peking University People’s Hospital between January 2012 and December 2016. Clinical characteristics and preoperative serum calcium, albumin, carbohydrate antigen (CA)125, CA19-9, carcinoembryonic antigen (CEA) were extracted from patient records and evaluated according to postoperative peritoneal cytology. Predictive factors were assessed with Cox univariate and multivariate analyses. Factors selected from multivariate analysis results were used to build a predictive model. RESULTS: A total of 510 patients are identified in our database and 444 patients who fulfilled inclusion and exclusion criteria are included in this study. Univariate analysis revealed that ionized calcium concentration was closely related to positive peritoneal cytology, tumor grade and lymph-vascular space invasion (LVSI). Moreover, peritoneal cytology was significantly associated with hypertension, tubal ligation, serum CA125, CA19-9, CEA and ionized calcium level. Multivariate analysis revealed that albumin-adjusted calcium level, CA125 and tubal ligation were independent predictive factors of positive peritoneal cytology (P<0.05). A combination of ionized calcium level with the other two indexes yielded significantly great area under the curve (AUC=0.824). CONCLUSIONS: This study enhanced the value of preoperative ionized calcium level. We also identified several potential biomarkers to predict positive peritoneal cytology in EC patients before surgery.