Superiority of CRP-albumin-lymphocyte index as a prognostic biomarker for patients with gastric cancer

The new CRP-Albumin-Lymphocyte (CALLY) index is an immune nutrition scoring system based on serum C-reactive protein (CRP), serum albumin, and lymphocyte counts. This study aimed to verify the prognostic value of CALLY index in patients with gastric cancer and to evaluate the superiority of this new system. We retrospectively analyzed the data of patients with gastric cancer who were followed up from the INSCOC database between May 2013 and December 2018.Through simple random sampling, gastric cancer patients were divided into training group (n=684) and verification group (n=290) in a ratio of 7:3. Correlation analysis, Kaplan-Meier method and cubic spline function were used to analyze the relationship between CALLY index and overall survival (OS) in gastric cancer patients. Based on the results of COX regression analysis of training cohort, a nomogram model for predicting 1 -, 2 -, 3-and 5-year OS was established and verified internally. The prediction accuracy and benefit of nomogram in gastric cancer were evaluated by calibration and clinical decision curve, and compared with the traditional TNM gastric cancer staging system. The CALLY index was negatively correlated with the age of patients with gastric cancer (male, r=-0.1; female, r=-0.1), but positively correlated with BMI (male, r=0.063; female, r=0.058), and the cut-off value of the CALLY index was determined as 1.12. The OS of gastric cancer patients with CALLY index > 1.12 was significantly higher than that of gastric cancer patients with CALLY index ≤ 1.12 (P < 0.0001). There was an L-shaped dose-response relationship between CALLY index and the OS in patients with gastric cancer, and age, TNM stage, surgical treatment, chemotherapy, BMI and CALLY index were significantly correlated with the prognosis of patients with gastric cancer. Tumor TNM stage, BMI and CALLY index were independent risk factors affecting the prognosis of patients with gastric cancer, and CALLY index was protective factors in patients with gastric cancer under 65 years old, male, TNM3 stage, BMI 18.5-23.9, smoking, drinking, no radiotherapy and chemotherapy, operation, diabetes, hypertension and no family history of cancer, and had significant interaction with chemotherapy and operation. Nomogram based on TNM staging, BMI and CALLY index has good predictive ability and has clinical application value. Compared with traditional TNM staging system, nomogram has better resolution and accuracy in predicting 1 -, 2 -, 3-and 5-year OS. CALLY index can be used as an independent prognostic factor for patients with gastric cancer, and constructed a nomogram prediction model combining TNM staging, BMI and CALLY index, which had better prediction ability than traditional TNM staging.