ABSTRACT
Objective:To investigate the efficacy of CT imaging features in evaluating occult peritoneal metastasis (OPM) of diffuse infiltrating gastric cancer (Borrmann Type Ⅳ).Methods:Totally 101 patients with locally advanced Borrmann type Ⅳ gastric cancer were retrospectively collected who were admitted to Peking University Cancer Hospital from March 2014 to March 2021. The patients were divided into OPM group (53 cases) and the non-OPM group (48 cases) according to the results of preoperative CT and laparoscopic exploration/peritoneal cytology examination. The pathological examination results were recorded, including the degree of histological differentiation and Lauren classification. The evaluation indicators included the tumor center position, the number of tumor-occupied portions, involved orientation, mucosal broadband sign, stratified enhancement, serosa invasion, increased density of peripheral fat tissue, and enlarged lymph nodes. The maximum thickness of the primary tumor, average CT value of the primary tumor (arterial phase, venous phase, and delayed phase), difference between venous phase and arterial phase, difference between delayed phase and venous phase, and pattern of the enhanced curve were recorded. The Mann-Whitney U or Chi-square test was used to compare the differences of pathological and CT features between two groups. The multivariate logistic regression was used to screen independent predictors and establish a nomogram. The receiver operating characteristic curve was used to evaluate the performance of the nomogram in predicting OPM, and the Hosmer-Lemeshow test was used to test the model′s goodness of fit. Results:There was statistical significance in the seven indicators between the OPM and non-OPM groups, including tumor-occupied portions of stomach, mucosal broadband sign, stratified enhancement, serosa invasion, increased density of peripheral fat tissue, the enhanced curve pattern and the degree of histological differentiation ( P<0.05). Among them, the degree of histological differentiation (OR=0.19, P=0.033), stratified enhancement (OR=7.02, P=0.005) and serosa invasion (OR=14.27, P<0.001) were independent predictors of OPM. The nomogram was established based on the three significant features. The area under the curve for predicting OPM was 0.826 (95%CI 0.745-0.908), the sensitivity was 0.566 and the specificity was 0.938. The Hosmer-Lemeshow test showed a good agreement between the OPM risk predicted by the nomogram and the actual risk ( P=0.525). Conclusions:The CT features of Borrmann type Ⅳgastric cancer complicated with OPM have specific characteristics. The diagnosis model based on the degree of histological differentiation, stratified enhancement, and serosa invasion had high efficacy in evaluating OPM.
ABSTRACT
Objective:To investigate the predictive value of visceral adipose tissue (VAT) in occult peritoneal metastasis (OPM) of gastric cancer.Methods:A total of 93 patients with gastric cancer admitted to the First Affiliated Hospital of Zhengzhou University from October 2018 to October 2021 were retrospectively collected. None of the patients had typical peritoneal metastasis on CT. Patients were divided into OPM group (31 cases) and non-OPM group (62 cases) according to laparoscopic exploration. The clinical, pathological and CT features were recorded. The parameters related to adipose tissue (VAT and subcutaneous adipose tissue) within the range of 15 mm and 25 mm below the largest layer of gastric cancer lesions in preoperative CT images were measured, including the volume, average CT attenuation and standard deviation. The independent-sample t test, Wilcoxon rank-sum test, χ 2 test or Fisher′s exact probability were used to compare the clinical, pathological and CT imaging parameters between OPM and non-OPM groups. Multivariate logistic regression analysis was used to explore the independent risk factors for OPM of gastric cancer and establish a combined model. The receiver operating characteristic curve was used to evaluate the efficacy of each indicator and the combined model in predicting OPM of gastric cancer. Results:There were statistically significant differences in age, pathological type, CA125, ascites, cT stage, the thickest diameter of lesion, average CT attenuation of 15 mm VAT and 25 mm VAT between the OPM group and the non-OPM group ( P<0.05). Multivariate analysis showed that ascites, cT stage and average CT attenuation of 25 mm VAT were independent risk factors for OPM of gastric cancer, with the OR (95%CI) of 4.940 (1.287-18.967), 4.284 (1.270-14.455), and 1.149 (1.013-1.303), respectively. A combined model was established. The area under the curve (AUC) of ascites, cT stage, average CT attenuation of 25 mm VAT, average CT attenuation of 15 mm VAT and combined model were 0.685, 0.718, 0.703, 0.674 and 0.813, respectively. There were statistically significant differences in AUC between the combined model and each four single indicators above ( Z=2.98, 2.63, 2.09, 2.54, P=0.003, 0.009, 0.037, 0.011). Conclusions:The ascites, cT stage and average CT attenuation of 25 mm VAT are independent risk factors for OPM in gastric cancer. The combined model based on the above three indicators has the best performance in predicting OPM in gastric cancer.