Abstract: Objective To investigate the predictive value of preoperative albumin to alkaline phosphatase ratio (AAPR) in prognosis of patients after radical gastrectomy. Methods A total of 357 gastric cancer patients who underwent gastrectomy in Chongming Branch of Xinhua Hospital Affiliated to Medical College of Shanghai Jiao Tong University from June 2014 to November 2019 were retrospectively recruited as the research objects, and the follow-up was until December 2020. The optimal cut-off value of AAPR was calculated by the maximum selection rank statistics and the patients were divided into the high AAPR group and the low AAPR group. The Kaplan-Meier method and the Cox proportional hazards model were used to analyze the relationship between AAPR and disease-free survival (DFS) and overall survival (OS). The AAPR-TNM system was constructed by combining AAPR and TNM stage, and the predictive abilities of TNM staging system and AAPR-TNM system on DFS and OS were compared by the likelihood ratio test (LRT), AIC and C-index. Results The optimal cut-off value of AAPR was 0.412. 3-year DFS rate and OS rate of patients in the high AAPR group were higher than those in the low AAPR group (78.5% vs 38.1%, log-rank χ²=49.652, P<0.001; 87.2% vs 51.1%, log-rank χ²=33.532, P<0.001). After adjusting for potential confounding factors, high AAPR was a protective factor for DFS (HR=0.25, 95%CI: 0.15-0.42) and OS (HR=0.24, 95%CI: 0.13-0.39). Compared with the TNM staging system, the AAPR-TNM system had a larger LRT χ² value, a smaller AIC and a higher C-index (all P<0.001). Conclusions The prognosis of gastric cancer patients with low preoperative AAPR level is poor after radical gastrectomy, and AAPR combined with TNM stage has better predictive ability than TNM staging system in postoperative prognosis.

Key words: Gastric cancer, Albumin to alkaline phosphatase ratio, Disease-free survival, Overall survival