Predictive value of serum calcium ion level in patients with colorectal cancer: A retrospective cohort study
Yin Shu, Ke-Jin Li, Subinur Sulayman, Ziyi Zhang, Saibihutula Ababaike, Kuan Wang, Xiangyue Zeng, Yi Chen, Zeliang Zhao
Abstract
BACKGROUND Serum calcium ion (Ca2+) is an economical and readily available indicator as a routine screening test for hospitalized patients. There are no studies related to serum Ca2+ level and digestive tract malignancy. AIM To evaluate the effectiveness of serum Ca2+ level in predicting the prognosis of patients with colorectal cancer (CRC). METHODS We retrospectively collected the data of 280 patients diagnosed with CRC who underwent radical surgery at the Affiliated Cancer Hospital of Xinjiang Medical University. By analyzing the clinicopathological features, differences between serum Ca2+ concentrations on the first day after surgery were determined. We used the receiver operating characteristic curve to assess the predictive ability of serum Ca2+ for survival. Survival analyses were performed using the Kaplan-Meier method, and multivariate Cox proportional risk regression was used to determine association between calibration serum Ca2+ levels and CRC survival outcomes. RESULTS By receiver operating characteristic curve analysis, the ideal threshold value for Ca2+ the first postoperative day and delta serum calcium (δCa2+) value were 1.975 and 0.245, respectively. Overall survival (OS) and progression-free survival (PFS) were better in both the high Ca2+ group and high δCa2+ group on the first postoperative day. The variables identified through univariate analysis were incorporated into multivariate analysis and showed that tumor differentiation (P = 0.047), T stage (P = 0.019), N stage (P < 0.001), nerve vascular invasion (P = 0.037), carcinoembryonic antigen (P = 0.039), baseline serum Ca2+ level (P = 0.011), and serum Ca2+ level on the first day (P = 0.006) were independent predictors of prognosis for patients undergoing feasible radical CRC surgery. Using the findings from the multifactorial analysis, we developed a nomogram and the calibration showed a good predictive ability. CONCLUSION Low serum Ca2+ level on the first postoperative day is an independent risk factor for OS and PFS in CRC.