Predictive value of serum calcium ion level in patients with colorectal cancer: A retrospective cohort study

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.

Keywords: Serum calcium ion; Colorectal cancer; Prognosis; Nomogram; Overall survival

Core Tip: Serum calcium ion (Ca²⁺) is a readily available and cost-effective marker used in routine screenings but has not been studied in relation to digestive tract malignancies until now. This study examined the association of serum Ca²⁺ concentrations with clinical indicators in patients with colorectal cancer (CRC) undergoing radical surgery. The results show that reduced serum Ca²⁺ concentrations on the first day after surgery are associated with poorer overall survival and progression-free survival in patients with CRC.