Clinical application value of receiver operator characteristic curve in selecting optimal cutoff value for gastric cancer tumor markers

Xu Jin; Zhang Qingsong; Sun Douzhi

doi:10.3969/j.issn.1674-7151.2024.01.005

Abstract：Objective To analyze the clinical application value of receiver operator characteristic(ROC)curve in selecting optimal cutoff value for gastric cancer tumor markers.Methods Sixty patients diagnozed with gastric cancer and admitted to Langxi County People's Hospital from January 2020 to December 2022 were selected as research objects and included in gastric cancer group.In addition,60 patients with benign gastric lesions and 60 healthy examinees during the same period were included in gastric disease group and control group.Chemiluminescence was used to detect carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA19-9),and carbohydrate antigen 72-4(CA72-4),and the positive rates of different indicators in each group were compared.The ROC curve was drawn and the area under ROC curve(AUC)was calculated.The optimal cutoff values for CEA,CA19-9 and CA72-4 were selected,and the diagnostic efficacies of different indicators for gastric cancer under these cutoff values both individually and in combination were calculated.Results The positive rates of CEA,CA19-9 and CA72-4 in gastric cancer group were significantly higher than those in control group(CEA:55.00%vs.0.00%;CA19-9:50.00%vs.0.00%;CA72-4:46.67%vs.0.00%;all P＜0.05).The Jordan indices for diagnosing gastric cancer using CEA,CA19-9,CA72-4 alone and in combination were 0.517,0.458,0.442 and 0.617,respectively.The ROC curve showed that CEA[AUC was 0.838,95%confidence interval(95%CI)was 0.770-0.907],CA19-9(AUC was 0.836,95%CI was 0.769-0.902)and CA72-4(AUC was 0.855,95%CI was 0.796-0.914)had high diagnostic efficacies for gastric cancer,and the combined use of three indicators was more effective(AUC was 0.946,95%CI was 0.909-0.984).The optimal cutoff values for CEA,CA19-9 and CA72-4 were 5.77 μg/L,29.52 kU/L and 5.06 kU/L,respectively.At these cutoff values,the Jordan indices for differential diagnosis of gastric cancer using CEA,CA19-9 and CA72-4 alone and in combination were 0.616,0.625,0.641 and 0.816,respectively.Conclusion CEA,CA19-9 and CA72-4 all have high diagnostic value for gastric cancer,and the combination of multiple indicators and the establishment of the optimal cutoff value suitable for the laboratory could further improve the diagnostic efficiency,providing reference basis for early diagnosis and timely treatment of gastric cancer in clinical practice.