Preoperative Low Serum Calcium Levels Predict Poor Prognosis for Patients with Esophageal Cancer

Purpose: Hypercalcemia has been reported as a poor prognostic factor in malignant tumors. However, no report has shown the clinical impact of serum calcium levels on patients with esophageal cancer. We evaluated the prognostic impact of preoperative serum calcium levels on patients with esophageal cancer. Methods: We evaluated 240 patients (197 men, 43 women; mean age, 66 years; age range, 34-85 years) with esophageal cancer who underwent radical surgery between September 2008 and December 2017. After assigning the patients to two groups (high calcium group, 8.8 mg/dL or more and low calcium group, 8.7 mg/dL or less), we compared the groups' overall survival and the clinicopathological features. The clinicopathological and prognostic significance of preoperative serum calcium levels were evaluated in a univariate and multivariate analysis. Results: The patients with deep tumors showed low serum calcium levels significantly more frequently (P <0.05). The low calcium group showed a significantly worse prognosis than the high calcium group (P <0.05). However, low serum calcium level was not an independent poor prognostic factor. Conclusions: Preoperative low serum calcium levels were associated with advanced tumors. Low serum calcium might be associated with esophageal cancer progression.