Clinicopathologic Features of Submucosal Papillary Gastric Cancer Differ from Those of Other Differentiated-Type Histologies

Concordance between microsatellite instability testing and immunohistochemistry for mismatch repair proteins and efficient screening of mismatch repair deficient gastric cancer

Microsatellite instability (MSI) testing, an established technique that has gained prominence in recent years for its predictive potential regarding the efficacy of immune checkpoint inhibitors, is used to evaluate DNA mismatch repair (MMR) deficiency (dMMR). As with other methods, the immunohistochemistry (IHC) of MMR proteins is also widely adopted. Although both techniques have been validated, their concordance rate remains unknown, particularly regarding non-colorectal cancer. Therefore, the aim of the present study was to explore and elucidate their concordance in the context of gastric cancer (GC). A total of 489 surgically resected primary GC tissues were analyzed to compare the results yielded by the MSI test and those from IHC. Of 488 GC cases, 56 (11.5%) exhibited a loss of MMR proteins, whereas 52 (10.7%) were classified as high-frequency MSI (MSI-H). The concordance rate between these two categories was 99.2%. The microsatellite markers BAT26 and MONO27 demonstrated 100% sensitivity and 99.5% specificity in detecting dMMR GC. In addition, histopathological analysis revealed that MSI-H was more prevalent in GCs exhibiting coexisting Tub2 and Por1 subtypes. However, four discordant cases were observed. All four cases were microsatellite-stable cases but exhibited loss of MLH1 protein expression with hypermethylation of the MLH1 promoter. The results of the present study highlight that while there is a strong concordance between MSI and IHC testing results for determining dMMR status, IHC testing may offer superior efficacy in detecting dMMR.

A Retrospective Cohort Study of Factors Influencing Lymph Node Metastasis in Patients With Early Gastric Papillary Adenocarcinoma

INTRODUCTION

High risk of lymph node metastasis (LNM) in gastric papillary adenocarcinoma causes endoscopists to worry about the suitability of endoscopic resection for early gastric papillary adenocarcinoma (EPAC). We compared risk factors and attempted to establish a scoring system to stratify LNM risk in patients with EPAC.

METHODS

A retrospective analysis was performed on 2,513 patients with early gastric carcinoma (EGC) who underwent radical resection in 4 tertiary hospitals in China. Univariate and multivariate analyses were performed to compare the invasiveness in EPAC and other types of EGC and to evaluate potential factors in predicting LNM risk in EPAC groups.

RESULTS

Three hundred thirty-five patients with EPAC were enrolled in our study, of which 62 patients were found to have LNM. After comparing clinicopathological characteristics of EPAC with and without LNM, the following factors were included in the risk scoring system: 1 point each for lower stomach location and tumor size >2.0 cm, 3 points for lymphovascular invasion, and 4 points for submucosal invasion; the risk scoring system was validated in a small internal validation set with an area under the curve of 0.844.

DISCUSSION

Our results suggested that EPAC was highly invasive compared with other EGCs, especially differentiated EGC types, and need to be treated more rigorously. This proposed risk scoring system could stratify LNM risk in patients with EPAC, and endoscopic resection may only be performed safely on the groups with a low LNM rate.

Application of preoperative CT texture analysis in papillary gastric adenocarcinoma

Background

This study aimed to analyze the ability of computed tomography (CT) texture analysis to discriminate papillary gastric adenocarcinoma (PGC) and to explore the diagnostic efficacy of multivariate models integrating clinical information and CT texture parameters for discriminating PGCs.

Methods

This retrospective study included 20 patients with PGC and 80 patients with tubular adenocarcinoma (TAC). The clinical data and CT texture parameters based on the arterial phase (AP) and venous phase (VP) of all patients were collected and analyzed. Two CT signatures based on the AP and VP were built with the optimum features selected by the least absolute shrinkage and selection operator method. The performance of CT signatures was tested by regression analysis. Multivariate models based on regression analysis and the support vector machine (SVM) algorithm were established. The diagnostic performance of the established nomogram based on regression analysis was evaluated by receiver operating characteristic curve analysis.

Results

Thirty-two and fifteen CT texture parameters extracted from AP and VP CT images, respectively, differed significantly between PGCs and TACs (all p < 0.05). The diagnostic performance of CT signatures based on the AP and VP achieved AUCs of 0.873 and 0.859 in distinguishing PGCs. Multivariate models that integrated two CT signatures and age based on regression analysis and the SVM algorithm showed favorable performance in preoperatively predicting PGCs (AUC = 0.922 and 0.914, respectively).

Conclusion

CT texture analysis based multivariate models could preoperatively predict PGCs with satisfactory diagnostic efficacy.

Clinicopathological features and CT findings of papillary gastric adenocarcinoma

PURPOSE

This study aimed to analyze the clinicopathological and computed tomography (CT) findings of papillary gastric adenocarcinoma and to evaluate the feasibility of the multivariate model based on clinical information and CT findings for discriminating papillary gastric adenocarcinomas.

METHODS

This retrospective study included 22 patients with papillary gastric adenocarcinoma and 88 patients with tubular adenocarcinoma. The demographic data, tumor markers, histopathological information, CT morphological characteristics, and CT value-related parameters of all patients were collected and analyzed. The multivariate model based on regression analysis was performed to improve the diagnostic efficacy for discriminating papillary gastric adenocarcinomas preoperatively. The diagnostic performance of the established nomogram was evaluated by receiver operating characteristic curve analysis.

RESULTS

The distribution of age, carcinoembryonic antigen, differentiation degree, neural invasion, human epidermal growth factor receptor 2 overexpression, P53 mutation status, 4 CT morphological characteristics, and 10 CT valued-related parameters differed significantly between papillary gastric adenocarcinoma and tubular adenocarcinoma groups (all p < 0.05). The established multivariate model based on clinical information and CT findings for discriminating papillary gastric adenocarcinomas preoperatively achieved the area under the curve of 0.920.

CONCLUSION

There existed differences in clinicopathological features and CT findings between papillary gastric adenocarcinomas and tubular adenocarcinomas. The combination of demographic data, tumor markers, CT morphological characteristics, and CT value-related parameters could discriminate papillary gastric adenocarcinomas preoperatively with satisfactory diagnostic efficiency.

Papillary Adenocarcinoma

Gastric papillary adenocarcinoma is one of the histological variants of gastric cancer that shows more aggressive clinicopathological behavior compared to tubular adenocarcinoma. Previous studies have reported higher lymphovascular and submucosal invasion rates for papillary adenocarcionoma than those of tubular adenocarcinoma. However, the current guidelines categorize papillary adenocarcinoma and tubular adenocarcinoma together as differentiated-type tumor and have recommended the same endoscopic submucosal dissection criteria. Thus, concerns have been raised regarding the appropriateness of the current policy. To validate the current guidelines, the lymph node metastasis rate from surgical specimen studies as well as the long-term outcomes of endoscopic submucosal dissection for papillary adenocarcinomas need to be taken into consideration. In this review, I aimed to review the current understanding of the clinical and pathological features of papillary adenocarcinoma. In addition, I aimed to generate an integrated view regarding the outcomes of endoscopic submucosal dissection and surgery for papillary adenocarcinoma in order to evaluate the appropriateness of the current guidelines.