| Objective:1.To explore the differences of clinical and pathological features between young patients with gastric cancer and middle-aged and elderly patients with gastric cancer,and the relationship between multi-parameter values of energy spectral CT and differential factors.2.Based on the results of multivariate analysis,the risk prediction models(nomogram)for the diagnosis of young patients with gastric cancer and middle-aged and elderly patientss with gastric cancer were established to provide guidance for the screening and diagnosis.Materials and methodsThe clinical data and energy spectral CT data of 112 patients with gastric adenocarcinoma who met the inclusion criteria of this study from March 2018 to February 2019 in the first affiliated Hospital of Zhengzhou University were collected retrospectively.the clinical data included sex,tumor location,histological classification,differentiation,stage and immunohistochemical gene expression extracted from medical history,endoscope and pathological system.The data of energy spectral CT included the maximum diameter of the tumor,the CT value of arterial phase(artery,AP)and venous phase(portal,PP),the iodine base value of arteriovenous phase(iodine concentration,IC),and the standardized iodine base value of arteriovenous phase(normalized iodine concentration,NIC)was obtained from the IC value of arteriovenous phase and the iodine base value of abdominal aorta at the same level.According to the age?40 years old,the patients were further divided into young gastric cancer group and middle-aged gastric cancer group,including 42 young gastric cancer patients,13 males and 29 females,aged 23-40 years,with an average age of(33.2±5.2)years.There were 70 middle-aged and elderly patients with gastric cancer,including 51 males and 19 females,ranging from 43 to 79 years old,with an average age of(61.7±9.9)years.Chi-square test or Fisher's exact test was used to analyze the differences between classified variables,two independent samples t-test or Mann-Whitney U test were used for univariate analysis of continuous variables,and nomogram was constructed according to the results of logistic multivariate regression analysis.The diagnostic efficacy of single factor and multiple factors was evaluated by drawing the subject working characteristic curve(receiver operating characteristic,ROC)and the area under the curve(the area under curve,AUC).The corresponding point of the maximum Jordan index(Youden's index)on the ROC curve was taken as the best boundary value,and the sensitivity and specificity of diagnosis under the best cutoff value were obtained.Result1.General clinical data of young patients with gastric cancer and middle-aged and elderly patients with gastric cancer.In the young gastric cancer group,most of the patients were female,with a male-to-female ratio of 1:2.2;tumors occurred in the gastric antrum in 26 cases,accounting for 61.9%;signet ring cell carcinoma was predominant;and most of them were poorly differentiated gastric cancer.There was a large proportion of male patients in the middle-aged and elderly gastric cancer group,with a male-to-female ratio of 2.68:1;cardia and gastric fundus was the most common site in 37 cases,accounting for 52.9%;the proportion of non-signet ring cell cancer was higher;and the proportion of highly differentiated gastric cancer was higher than that of the young group.In terms of the depth of invasion,the proportion of T4 gastric cancer in the middle-aged and elderly gastric cancer group was higher than that in the young gastric cancer group.There were significant differences in incidence,tumor location,histological classification,degree of differentiation and depth of invasion between the two groups(P<0.05).2.Analysis of clinicopathological characteristics and construction of nomogram in young gastric cancer group based on energy spectral CT.Histological classification:the values of CT-AP,CT-PP,IC-AP and NIC-AP in signet ring cell carcinoma were significantly higher than those in non-signet ring cell carcinoma.The results of multivariate regression analysis showed that the values of CT-AP,CT-PP,IC-AP and NIC-AP did not predict that the histological type was an independent risk factor for signet ring cell carcinoma.Degree of differentiation:most of the tumors in patients with poorly differentiated gastric cancer were located in the antrum,which was significantly different from that in patients with moderately and well differentiated gastric cancer(P<0.05).The values of energy spectral CT parameters CT-PP,IC-PP and NIC-PP were significantly higher in patients with moderately and well differentiated gastric cancer than those in patients with moderately and well differentiated gastric cancer(all P<0.05).Multivariate regression analysis showed that tumor location,IC-PP and NIC-PP were independent risk factors for poor differentiation.A nomogram model was constructed to predict the risk of low differentiation in the young gastric cancer group.the area under the ROC curve(AUC)was 0.795.When 0.265 was used as the threshold,the diagnostic efficiency was the highest,and the sensitivity and specificity were 90.9%and 55.6%,respectively.The depth of invasion:the maximum diameter of tumor in T4 gastric cancer patients was larger than that in non-T4 gastric cancer patients,and the difference was statistically significant(P<0.05).The area under the ROC curve AUC was 0.752,and the diagnostic sensitivity and specificity were 72.2%and 79.2%,respectively.3.Analysis of clinicopathological characteristics and construction of nomogram in middle-aged and elderly group based on energy spectral CT.Histological classification:the value of CT-PP in patients with signet ring cell carcinoma was significantly higher than that in patients with non-signet ring cell carcinoma.CT-PP as an independent risk factor for signet ring cell cancer,the area under the ROC curve(AUC)was 0.811,and the diagnostic sensitivity and specificity were 59.1%and 100.0%,respectively.Degree of differentiation:the average age of patients with poorly differentiated gastric cancer was lower than that of patients with moderately and highly differentiated gastric cancer,and the probability of male patients was lower than that of patients with moderately and well differentiated gastric cancer,and the difference was statistically significant(all P<0.05).The values of energy spectral CT parameters CT-AP,CT-PP,IC-AP,IC-PP and NIC-PP were significantly higher in patients with moderately and well differentiated gastric cancer than those in patients with moderately and well differentiated gastric cancer(all P<0.05).Multivariate regression analysis showed that sex and NIC-PP were independent risk factors for poor differentiation.The nomogram model for predicting the risk of low differentiation in the middle-aged and elderly gastric cancer group was constructed.The area under the ROC curve AUC of the nomogram was 0.812.When 0.326 was used as the threshold,the diagnostic efficiency was the highest,and the sensitivity and specificity were 92.9%and 73.8%,respectively.Depth of invasion:the average age of T4 gastric cancer patients was older than that of non-T4 gastric cancer patients,and most of the tumors were located in cardia and gastric fundus,and the maximum diameter of tumor was larger than that of non-T4 gastric cancer patients,the difference was statistically significant(all P<0.05).The results of multivariate regression analysis showed that age was an independent risk factor for predicting T4 gastric cancer.The area under the ROC curve(AUC)was 0.765,and the diagnostic sensitivity and specificity were 59.6%and 91.3%,respectively.Conclusion1.Energy spectral CT can be used as an effective diagnostic method to evaluate the preoperative clinicopathological features of young patients with gastric cancer and middle-aged and elderly patients.2.The nomogram diagnostic model established by energy spectral CT parameters such as venous iodine base value(IC-PP),venous standardized iodine base value(NIC-PP)and tumor location has good clinical value in predicting the risk of poor differentiation in young patients with gastric cancer.The nomogram diagnostic model established by energy spectral CT parameters venous phase standardized iodine base value(NIC-PP)and patient sex has good clinical value in predicting the risk of poor differentiation in middle-aged and elderly patients with gastric cancer.3.In view of the different risk prediction indexes of low differentiation degree between young gastric cancer and middle-aged and elderly patients with gastric cancer,age should be considered when evaluating the degree of differentiation of gastric cancer by energy spectral CT imaging. |
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