Is Preoperative Low Serum Calcium Level a Poor Prognostic Factor of Gastric Cancer?

Introduction: Few reports evaluated the prognostic impact of hypocalcemia in patients with cancer. In this study, we evaluated the clinicopathological and prognostic significance of preoperative serum calcium level in patients with gastric cancer. Methods: We analyzed preoperative serum calcium levels in 758 patients (514 men and 244 women) who underwent radical surgery for gastric cancer between 2004 and 2017. The cutoff value of calcium level was fixed to 8.7 mg/dL based on receiver operating characteristic curve analysis. We compared the patients' clinicopathological characteristics between the low- and high calcium groups based on this cutoff value. We employed univariate and multivariate analyses to evaluate the clinicopathological and prognostic significance of preoperative low serum calcium levels. Results: The low serum calcium level was significantly associated with old age, deep tumor depth, positive nodal status, positive distant metastasis, low serum albumin, high C-reactive protein, and high white blood cell count. The low serum calcium group exhibited a significantly worse overall survival than the high serum calcium group (P < 0.001). The survival difference was significant only in stage I cancer patients; however, young patients did not have this tendency. The low serum calcium level was an independent risk factor for poor overall survival in stage I cancer elderly patients. Conclusions: Preoperative low serum calcium level was associated with poor overall survival in patients with gastric cancer. This prognostic impact was particularly evident in stage I cancer elderly patients.