The efficacy of CT imaging features in evaluating occult peritoneal metastasis of diffuse infiltrating gastric cancer / 中华放射学杂志

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.