Gastric cancer: imaging and staging with MDCT based on the 7th AJCC guidelines

RORα inhibits proliferation and chemoresistance through AKR1A1-induced glucose and lipid reprogramming in gastric cancer

BACKGROUND

Abnormal glycolysis and lipid metabolism play important roles in the occurrence and development of gastric cancer (GC). Moreover, dysregulation of circadian genes is associated with metabolic reprogramming in the tumor microenvironment. This study aimed to determine the role of retinoic acid-related orphan receptor alpha (RORα) in glucose and lipid reprogramming in GC.

METHODS

The effects on cell proliferation and chemoresistance in vitro and in vivo were studied using gain- and loss-of-function experiments. Glycolytic activity and lipid synthesis were assessed using a Seahorse assay and reagent kits. Moreover, the regulatory mechanisms were explored using half-life, coimmunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), luciferase reporter and immunofluorescence colocalization assays in GC cells. In addition, the relationships of RORα with E47 and AKR1A1 were analyzed using public databases and retrospective clinicopathological analyses.

RESULTS

RORα deletion promoted cell proliferation and fluorouracil (5-FU) chemoresistance by increasing glycolytic activity and lipid synthesis. In contrast, SR1078, an RORα activator, reversed these changes and had a synergistic inhibitory effect on cell proliferation in combination with 2-deoxygulose glucose (2-DG) or atorvastatin. Mechanistically, aldo-keto reductase family 1 member A1 (AKR1A1), is the key driver of RORα-mediated glucose and lipid reprogramming. Specifically, E47 is an AKR1A1 transcription factor, and its stability is affected by β-catenin. RORα deletion indirectly promoted E47 protein stability through the up-regulation of β-catenin, leading to increased AKR1A1 transcriptional activity. Moreover, RORα, E47 and AKR1A1 expression was dysregulated, and associated with clinicopathological parameters and prognosis in patients with GC. These expression patterns including RORα-low, E47-high and AKR1A1-high expression patterns alone or in combination were correlated with reduced responsiveness, poor prognosis, increased standard uptake value (SUV) levels and lipid droplet formation.

CONCLUSIONS

These findings reveal a novel mechanism by which RORα regulates glucose and lipid reprogramming and may be a promising target for GC treatment.

Radiomics analysis of dual-energy CT-derived iodine maps for differentiating between T1/2 and T3/4a in gastric cancer: A multicenter study

OBJECTIVE

To investigate the value of radiomic analysis of dual-energy CT (DECT)-derived iodine maps (IMs) for the differentiation between T1/2 and T3/4a stage tumors in gastric cancer (GC).

METHODS

A total of 263 patients who received upfront surgery and were pathologically confirmed with gastric adenocarcinoma were enrolled in this study. Dual-phase enhanced CT scans with gemstone spectral imaging (GSI) mode were performed within two weeks before surgery. 151 patients were retrospectively collected for the training (n = 105) and validation (n = 46) cohorts, and 112 patients were prospectively collected for the external test1 (n = 68) and external test2 (n = 44) cohorts. According to the postoperative pathological T stage, patients were classified into T1/2 and T3/4a stage groups. Clinical characteristics were recorded and quantitative iodine concentration (IC) of tumors was measured. Radiomics features were extracted from the venous phase (VP) IMs by three-dimensional region of interest (3D-ROI) segmentation. Feature selection was performed using the least absolute shrinkage and selection operator. Four machine learning algorithms, including random forest, logistic regression, naive Bayes, and support vector machine, were used to construct radiomics models. Finally, the most valuable clinical characteristics, DECT parameters, and the best radiomics model were combined to build a nomogram. The diagnostic performance of nomogram was evaluated by the area under receiver operating characteristic curve (AUC), calibration curve, and decision curve.

RESULTS

The nomogram combined tumor clinical T stage (cT), tumor thickness, venous-phase iodine concentration (ICVP), normalized arterial-phase iodine concentration (nICAP), and Radscore (derived from logistic regression model). This integrated model demonstrated favorable performance in the differentiation between T1/2 and T3/4a stage tumors in GC, with AUCs of 0.892 (95 %CI: 0.829-0.956), 0.846 (95 %CI: 0.734-0.958), 0.894 (95 %CI: 0.818-0.970) and 0.821 (95 %CI: 0.689-0.952) observed for the training, validation, external test 1, and external test 2 cohorts, respectively. Hosmer-Lemeshow test showed a good fit (all P > 0.05). Decision curves confirmed that the nomogram provided more net clinical benefit than the default simple strategy over a wide range of threshold probabilities.

CONCLUSION

We have developed and validated a multidimensional personalized nomogram that integrates a radiomics model based on DECT-derived IMs, DECT quantitative parameters, and traditional clinical features. The proposed model demonstrated favorable performance in preoperative identification of T3/4a stage tumors in GC.

Comparison of the diagnostic accuracy of enhanced-CT and double contrast-enhanced ultrasound for preoperative T-staging of gastric cancer: a meta-analysis

BACKGROUND

Accurate preoperative staging of gastric cancer (GC) depends on effective diagnostic methods. Enhanced computed tomography (enhanced-CT) is a widely used and reliable preoperative assessment tool for GC, Double Contrast-Enhanced Ultrasound (DCEUS) can display the structure and layers of the gastric wall more accurately, and has high sensitivity (SE) and specificity (SP).

OBJECTIVE

The present study aims to conduct a comprehensive meta-analysis comparing the preoperative T-staging accuracy of DCEUS and enhanced-CT.

METHODS

A systematic literature search was conducted across PubMed, Embase, Web of Science, and Cochrane Library to identify eligible articles from inception to February 19, 2024. The study included both prospective and retrospective studies involving patients with GC who underwent DCEUS or enhanced-CT. This encompassed studies utilizing comparative diagnostic test accuracy (CDTA) with both DCEUS and enhanced-CT, as well as studies employing single diagnostic test accuracy (SDTA) with either DCEUS or enhanced-CT alone. Risk of bias was assessed using the Quality Assessment Of Diagnostic Accuracy Studies-C (QUADAS-C) and Assessment Of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. The quality of evidence for each outcome was assessed using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

RESULTS

A total of 39 studies involving 6,374 patients were included in this meta-analysis. Among these, 3 studies (319 patients) directly compared dynamic contrast-enhanced ultrasound (DCEUS) and enhanced computed tomography (CT), while 31 studies (5,180 patients) evaluated enhanced CT alone, and 5 studies (875 patients) assessed DCEUS alone. For the direct comparison studies (CDTA), DCEUS demonstrated higher sensitivity (SE) and specificity (SP) for T1-T4 staging compared to enhanced CT, with moderate to low certainty of evidence. Specifically, DCEUS showed superior performance in detecting early-stage (T1) and advanced-stage (T4) tumors. Enhanced CT, while effective, had lower sensitivity across all stages, particularly for T1 tumors. In the single-modality studies (SDTA), DCEUS consistently showed higher sensitivity for T2-T4 staging compared to enhanced CT, with comparable specificity. However, the certainty of evidence for indirect comparisons was very low, highlighting the need for further high-quality comparative studies. Overall, DCEUS appears to be a promising modality for gastric cancer T staging, particularly for early-stage detection, but the limited number of direct comparative studies underscores the need for more robust evidence.

CONCLUSION

Current evidence indicates that DCEUS significantly outperforms enhanced-CT in terms of SE and diagnostic accuracy for preoperative T-staging of GC, while maintaining comparable SP. However, these findings require further validation through rigorous studies with larger sample sizes and improved methodological quality.

A quantitative model using multi-parameters in dual-energy CT to preoperatively predict serosal invasion in locally advanced gastric cancer

OBJECTIVES

To develop and validate a quantitative model for predicting serosal invasion based on multi-parameters in preoperative dual-energy CT (DECT).

MATERIALS AND METHODS

A total of 342 LAGC patients who underwent gastrectomy and DECT from six centers were divided into one training cohort (TC), and two validation cohorts (VCs). Dual-phase enhanced DECT-derived iodine concentration (IC), water concentration, and monochromatic attenuation of lesions, along with clinical information, were measured and collected. The independent predictors among these characteristics for serosal invasion were screened with Spearman correlation analysis and logistic regression (LR) analysis. A quantitative model was developed based on LR classifier with fivefold cross-validation for predicting the serosal invasion in LAGC. We comprehensively tested the model and investigated its value in survival analysis.

RESULTS

A quantitative model was established using IC, 70 keV, 100 keV monochromatic attenuations in the venous phase, and CT-reported T4a, which were independent predictors of serosal invasion. The proposed model had the area-under-the-curve (AUC) values of 0.889 for TC and 0.860 and 0.837 for VCs. Subgroup analysis showed that the model could well discriminate T3 from T4a groups, and T2 from T4a groups in all cohorts (all p < 0.001). Besides, disease-free survival (DFS) (TC, p = 0.015; and VC1, p = 0.043) could be stratified using this quantitative model.

CONCLUSION

The proposed quantitative model using multi-parameters in DECT accurately predicts serosal invasion for LAGC and showed a significant correlation with the DFS of patients.

CRITICAL RELEVANCE STATEMENT

This quantitative model from dual-energy CT is a useful tool for predicting the serosal invasion of locally advanced gastric cancer.

KEY POINTS

Serosal invasion is a poor prognostic factor in locally advanced gastric cancer that may be predicted by DECT. DECT quantitative model for predicting serosal invasion was significantly and positively correlated with pathologic T stages. This quantitative model was associated with patient postoperative disease-free survival.

Low Absolute Lymphocyte Count Correlates with Lymph Node Metastases and Worse Survival of Patients with Gastric Cancer

BACKGROUND

Several studies have found that the absolute lymphocyte (ALC) or neutrophil count predicts the survival of patients with solid tumors, and that the neutrophil-to-lymphocyte ratio and the prognostic nutritional index are useful markers of gastric cancer prognosis. However, it remains unclear whether the ALC is prognostic of lymph node (LN) metastasis in patients with gastric cancer. In this study, we aimed to explore the impact of ALC on prognosis and distinctive clinical characteristics in patients with gastric cancer.

PATIENTS AND METHODS

The medical records of patients with gastric adenocarcinomas who underwent radical gastrectomy with curative intent at Seoul St. Mary's Hospital and Yeouido St. Mary's Hospital between January 2010 and December 2017 were reviewed. Of these, 4149 patients for whom preoperative white blood cell, neutrophil, and lymphocyte counts were available were enrolled.

RESULTS

In all 4149 patients, ALC gradually decreased as the pN stage increased. Those with an ALC of less than 1360 cells/μL were defined as a low-ALC group, and advanced cT and cN stages were the strongest risk factors for LN metastasis in both univariate and multivariate analyses; undifferentiated tumor histology and a low ALC were also significant risk factors. Patients of all stages in the ALC-low group exhibited poorer prognoses. The ALC-low group also exhibited a higher recurrence rate in a greater proportion of LNs.

CONCLUSIONS

In patients with gastric cancer, as the preoperative ALC decreases, the incidence of LN metastasis increases. A low ALC is associated with a high recurrence rate, particularly in LNs.

Preoperative diagnosis of metastatic lymph nodes by CT-histopathologic matching analysis in gastric adenocarcinoma using dual-layer spectral detector CT

OBJECTIVES

There still remain challenges to accurate diagnosis of lymph node (LN) involvement in gastric cancer (GC) on conventional CT. This study evaluated the quantitative data derived from dual-layer spectral detector CT (DLCT) for preoperative diagnosis of metastatic LNs compared to conventional CT images.

METHODS

Patients with adenocarcinoma scheduled for gastrectomy were enrolled in this prospective study from July, 2021, to February, 2022. Regional LNs were labeled on preoperative DLCT. The LNs were located and matched using carbon nanoparticle solution during surgery according to their locations and anatomic landmarks on preoperative images. The matched LNs were randomly split into training and validation cohorts in a ratio of 2:1. The DLCT quantitative parameters in the training cohort were investigated using logistic regression models to identify independent predictors of metastatic LNs, and these predictors were subsequently applied to the validation cohort. Receiver operating characteristic curves were compared between the DLCT parameters and conventional CT images.

RESULTS

Fifty-five patients were included in the study, with 267 successfully matched LNs (90 metastatic, 177 nonmetastatic). Independent predictors included arterial phase CT attenuation on 70-keV images, venous phase electron density, and clustered feature. These combination predictors had areas under the curve (AUC) of 0.855 and 0.907 in the training and validation cohorts, respectively. Compared to conventional CT criteria alone, the model had higher AUC and accuracy (0.741 vs. 0.907, 75.28% vs. 87.64%; p < 0.01) for LN diagnosis.

CONCLUSION

Incorporating DLCT parameters improved preoperative diagnosis of LN metastasis in GC, increasing the accuracy of clinical N stage.

CLINICAL RELEVANCE STATEMENT

Compared to conventional CT criteria, quantitative parameters from dual-layer spectral detector CT showed higher diagnostic efficacy for the preoperative diagnosis of lymph node metastases in gastric cancer, increasing the accuracy of clinical N stage.

KEY POINTS

• Quantitative parameters from dual-layer spectral detector CT are useful for the preoperative diagnosis of lymph node metastases in gastric adenocarcinoma, increasing the accuracy of clinical N stage. • The values for metastatic lymph nodes are higher than those of nonmetastatic ones. The arterial phase of CT attenuation on 70-keV images, venous phase of electron density, and clustered feature independently predicted lymph node metastases. • Prediction model had area under the curve of 0.907, sensitivity of 81.82%, specificity of 91.07%, and accuracy of 87.64% for the preoperative diagnosis of lymph node metastasis.

Prevalence of nodal metastases in the individual lymph node stations for different T-stages in gastric cancer: a systematic review

BACKGROUND

Gastrectomy with lymph node dissection is the cornerstone of curative treatment of gastric cancer. Extent of lymphadenectomy may differ depending on T-stage, as the rate of lymph node metastases may differ. The objective of this systematic review is to investigate and compare the prevalence of nodal metastases in the individual lymph node stations between different T-stages.

METHODS

Data reporting and structure of this systematic review follows the PRISMA checklist. The Medline and PubMed databases were systematically searched. The search included the following Mesh terms: "Stomach Neoplasms", "Lymphatic Metastasis" and "Lymph Node Excision". The primary outcome was the highest prevalence of nodal metastases per T-stage.

RESULTS

The initial search resulted in 175 eligible articles. Five articles met the inclusion criteria and were accordingly analyzed. Concerning the lymph node stations 1 to 7, the lymph nodes along the lesser gastric curvature (station 3) show the highest metastases rate (T1: 5.5%, T2: 21.9%, T3: 41.9%, T4: 71.0%). Concerning the lymph node stations 8 to 20, the lymph nodes around the common hepatic artery (station 8) show the highest metastases rate (T1: 0.8%, T2: 7.9%, T3: 14.0%, T4: 28.2%).

CONCLUSION

An overall low prevalence of nodal metastases in the individual lymph node stations in early, T1 gastric carcinomas and an overall high prevalence in more advanced, T3 and T4 gastric carcinomas endorse a more tailored approach based on the different gastric T-stages. In addition, a less extensive lymphadenectomy seems justified in early T1 carcinoma.

SYNOPSIS

This systematic review provides an overview of the prevalence of nodal metastases for the individual lymph node stations between different T-stages, showing an overall low prevalence in early, T1 gastric carcinomas and an overall high prevalence in the more advanced, T3 and T4 gastric carcinomas.

Effect of visceral adipose tissue on the accuracy of preoperative T-staging of gastric cancer

BACKGROUND

Due to the anatomical characteristics of the tumor and the specific variables of the patients, the accuracy of preoperative T-staging of gastric cancer needs to be further improved. This study investigated the effect of visceral adipose tissue (VAT) on the accuracy of clinical T-staging of gastric cancer.

METHODS

The clinical data of 455 patients who underwent gastrectomy from January 2013 to December 2018 were analyzed retrospectively. Taking the postoperative pathological results as the reference standard, the patients were divided into accurate staging group and mistaken staging group according to the comparison of clinical T stage (cT) and pathological T stage (pT). The individual characteristics of the two groups were compared, including visceral fat content at L2/L3 level calculated on computed tomography, age, sex, tumor size, tumor location (cardia, stomach body, stomach antrum), and degree of differentiation. Multivariate logistic regression was used to determine the independent factors affecting the accuracy of cT staging.

RESULTS

Among the 455 patients, 355 patients (78.0 %) had accurate preoperative cT staging and 100 patients (22.0 %) had inaccurate preoperative cT staging. The average area of VAT in the accurate staging group was (129.8 ± 72.6) cm² and that in the mistaken staging group was (74.6 ± 61.6) cm² (P < 0.001). The optimal cut-off value of VAT was 97.8 cm² calculated according to the Yoden index. Multivariate logistic regression analysis showed that VAT, tumor location and tumor size were independent predictors of cT accuracy.

CONCLUSIONS

Patients with lower visceral fat content (<97.8 cm²) based on L2/L3 level had a higher risk of false staging in preoperative clinical T staging.

Effect of Preoperative Tumor Under-Staging on the Long-term Survival of Patients Undergoing Radical Gastrectomy for Gastric Cancer

PURPOSE

This study aimed to evaluate the effect of preoperative tumor staging deviation (PTSD) on the long-term survival of patients undergoing radical gastrectomy for gastric cancer (RGGC).

MATERIALS AND METHODS

Clinicopathological data of 2,346 patients who underwent RGGC were retrospectively analyzed. The preoperative tumor-lymph node-metastasis (TNM) under-staging group (uTNM) comprised patients who had earlier preoperative TNM than postoperative TNM, and the no preoperative under-staging group (nTNM) comprised the remaining patients.

RESULTS

There were 1,031 uTNM (44.0%) and 1,315 nTNM cases (56.0%). Cox prognostic analysis revealed that PTSD independently affected the overall survival (OS) after surgery. The 5-year OS was lower in the uTNM group (41.8%) than in the nTNM group (71.6%). The patients less than 65 years old, with lower American Society of Anaesthesiologists score, 2-5 cm tumor located at the lower stomach, and cT1 or cN0 preoperative staging would more likely undergo D1+ lymph node dissection (LND) in uTNM (p < 0.05). Logistic analyses revealed that tumor size > 2 cm and body mass index ≤ 22.72 kg/m2 were independent risk factors of preoperative TNM tumor under-staging in patients with cT1N0M0 staging (p < 0.05).

CONCLUSION

Underestimated tumor staging is not rare, which possibly results in inadequate LND and affects the long-term survival for patients undergoing RGGC. D2 LND should be carefully performed in patients who are predisposed to this underestimation.

Naples Prognostic Score Predicts Tumor Regression Grade in Resectable Gastric Cancer Treated with Preoperative Chemotherapy

Despite recent progresses, locally advanced gastric cancer remains a daunting challenge to embrace. Perioperative chemotherapy and D2-gastrectomy depict multimodal treatment of gastric cancer in Europe, shows better results than curative surgery alone in terms of downstaging, micrometastases elimination, and improved long-term survival. Unfortunately, preoperative chemotherapy is useless in about 50% of cases of non-responder patients, in which no effect is registered. Tumor regression grade (TRG) is directly related to chemotherapy effectiveness, but its understanding is achieved only after surgical operation; accordingly, preoperative chemotherapy is given indiscriminately. Conversely, Naples Prognostic Score (NPS), related to patient immune-nutritional status and easily obtained before taking any therapeutic decision, appeared an independent prognostic variable of TRG. NPS was calculated in 59 consecutive surgically treated gastric cancer patients after neoadjuvant FLOT4-based chemotherapy. 42.2% of positive responses were observed: all normal NPS and half mild/moderate NPS showed significant responses to chemotherapy with TRG 1-3; while only 20% of the worst NPS showed some related benefits. Evaluation of NPS in gastric cancer patients undergoing multimodal treatment may be useful both in selecting patients who will benefit from preoperative chemotherapy and for changing immune-nutritional conditions in order to improve patient's reaction against the tumor.

Gut wrenching: cases of missed gastrointestinal tumors and their mimics on computed tomography

Computed tomography (CT) of the abdomen and pelvis is one of the most common imaging studies ordered through the emergency department (ED). Because these studies are ordered for the detection of acute abnormalities and due to the relatively low incidence in patients presenting through the ED, gastrointestinal tumors are commonly missed. Moreover, many CT findings of malignant tumors overlap with benign entities, which can present a diagnostic challenge. This review article will describe the common CT findings of gastric, small bowel, colon, and appendiceal cancer as well as some of the common benign gastrointestinal conditions with similar imaging findings.

Radiologic serosal invasion sign as a new criterion of T4a gastric cancer on computed tomography: diagnostic performance and prognostic significance in patients with advanced gastric cancer

PURPOSE

To investigate the diagnostic performance and prognostic significance of a new criterion for radiologic T4a staging on computed tomography (CT) in patients with advanced gastric cancer (AGC).

METHODS

Between January 2010 and April 2019, 101 patients with pathologically confirmed gastric cancer were collected. Among them, 53 patients with pathologic T3 and T4a cancers were included in this study. Three reviewers assessed preoperative CT scans for radiologic T staging in two sessions, independently and in consensus at a 2-week interval, while blinded about the pathologic T stage. The radiologic serosal invasion sign was defined as a nodular extension from the outer gastric wall reaching beyond the perigastric vascular plane and adopted as a new CT criterion for T4a cancer. We evaluated the diagnostic performance, interobserver agreement, and prognostic significance of this sign for the postoperative recurrence.

RESULTS

There were 46 pathologic T3 cancers (86.7%) and seven pathologic T4a cancers (13.2%). The diagnostic performance of the radiologic serosal invasion sign in the differentiation between T3 and T4a cancers was as follows: sensitivity, 91.3%; specificity, 71.43%; and accuracy, 88.68% for R1 and sensitivity, 78.26%; specificity, 85.71%; and accuracy, 79.25% for R2. The k-value was 0.64. Among the clinical and pathologic variables, radiologic T4a sign [hazard ratio (HR): 7.96; 95% confidence interval (CI) 2.36-26.86, p = 0.001], pathologic T4a (HR 9.82, 95% CI 2.35-40.95, p = 0.002), tumor size (HR 1.18, 95% CI 1.02-1.35, p = 0.026), and lymphovascular invasion (HR 6.39, 95% CI 1.42-28.75, p = 0.015) were the significant factors for postoperative recurrence.

CONCLUSIONS

Radiologic serosal invasion sign is reliable as a new CT criterion for T4a cancer staging in patients with advanced gastric cancer, demonstrating 80% to 88% accuracy. Radiologic serosal invasion sign can also serve as a prognostic factor for postoperative recurrence as well as pathologic T4a stage.

Which is the optimal management for locally advanced gastric cancer patients with TRG 0 and 1 after R0 resection?

Background

Neoadjuvant chemotherapy (NAC) followed by surgery currently offers promise as a strategy for patients with locally advanced gastric cancer (GC). However, there is limited evidence to guide treatment for TRG 0 and 1 patients with locally advanced GC after R0 resection. This study set out to explore the optimal management for TRG 0 and 1 patients with locally advanced GC after R0 resection.

Methods

The retrospective data of 154 TRG 0 and 1 patients with locally advanced GC following R0 resection who were treated between January 2012 and December 2018 were collected and analyzed. The Kaplan-Meier method was used to estimate the survival rate. Multivariate analysis was performed using the Cox proportional hazards model.

Results

The median follow-up was 34.1 (range, 6.6–90.9) months. Six patients (3.9%) were lost during follow-up. Of the 27 patients who experienced relapse, 12 died, including 2 patients who died of non-neoplastic causes. The 5-year recurrence-free survival (RFS) and 5-year overall survival (OS) were 71.6% (95% CI: 68.5–79.6) and 82.9% (95% CI: 76.9–86.1) for the whole cohort, respectively. Univariate analysis revealed that patients with carcinoembryonic antigen (CEA) <5.0 ng/ml after NAC (77.7% vs. 20.1%, P<0.001), distal gastrectomy (91.7% vs. 67.5%, P=0.046) had higher 5-year RFS. Meanwhile, combined resection (55.6% vs. 73.1%, P=0.042), major complications (42.7% vs. 80.50%, P<0.001), and lymph node metastasis (ypN+) (52.0% vs. 83.7%, P<0.001) had lower 5-year RFS. The multivariate analysis showed that CEA level after NAC (HR =2.876, 95% CI: 1.051–7.872, P=0.040), major complications (HR =2.432, 95% CI: 1.062–5.567, P=0.035), and lymph node metastasis (ypN+) (HR =3.183, 95% CI: 1.242–8.161, P=0.016) were independent prognostic factors.

Conclusions

TRG 0 and 1 patients with local GC after R0 resection following NAC had a good prognosis, especially patients with CEA <5.0 ng/mL after NAC, and those without major complications or lymph node metastasis. Monotherapy or no chemotherapy may offer options for treating TRG 0 and 1 patients without adverse prognostic factors.

Preoperative Tumor Staging of Gastric Cancer: Comparison of Double Contrast-Enhanced Ultrasound and Multidetector Computed Tomography

OBJECTIVES

The purpose of this study was to compare the sensitivity and specificity of double contrast-enhanced ultrasound (CEUS) and multidetector computed tomography (MDCT) in the preoperative tumor staging of gastric cancer (GC) to stratify patients for suitable treatment.

METHODS

Fifty-four patients with GC proved by histologic findings were included. The sensitivity and specificity of double CEUS and MDCT for tumor staging were calculated and compared. The differences between these methods were evaluated by using the area under the curve (AUC) from a receiver operating characteristic curve analysis.

RESULTS

There were no significant differences in AUC values for T1 and T2 stages between double CEUS and MDCT (P = .190 and .256, respectively). However, the sensitivity of double CEUS in the detection of the T1 stage was higher than that of MDCT (88% versus 75%). The AUC values of MDCT for T3 and T4 stages were 0.833 and 0.905, which were both significantly higher than those of double CEUS (0.759 and 0.696; P < .05). The sensitivities of double CEUS and MDCT for the T3 stage were both 89%, but the accuracy and specificity of double CEUS were lower than those of MDCT (76% versus 83% and 63% versus 78%). The specificities of double CEUS and MDCT for the T4 stage were both 98%, but the accuracy and sensitivity of double CEUS were lower than those of MDCT (85% versus 94% and 42% versus 83%).

CONCLUSIONS

Multidetector CT is superior to double CEUS for T3 and T4 GC, and double CEUS may be regarded as an important complementary method to MDCT.

Usefulness of histologic differences and perivascular infiltration for preoperative T staging of advanced gastric cancer using computed tomography

PURPOSE

This study aimed to determine whether histologic differences and perivascular infiltration are useful for clinical T staging of advanced gastric cancer (AGC).

MATERIALS AND METHODS

This retrospective study included 160 patients with pathologically confirmed AGC who had available preoperative stomach computed tomography (CT). Using stomach CT, they were classified according to standard T stage, histologic T stage, and perivascular T stage. Accuracy of each T stage criteria was analyzed. Perivascular infiltrations for the evaluation of prognosis were correlated with time to tumor progression by log-rank test.

RESULTS

There was a significant difference between the accuracies of the standard and histologic T stages (p < 0.001), whereas there was no significant difference between the standard and perivascular T stages (p = 0.07). In 121 patients who were pathologically confirmed as having T3 or T4a tumor, there was a significant difference between the standard and perivascular T stage (p < 0.001). In patients having T3 or T4a tumor, time to tumor progression of the negative perivascular infiltration subgroup was significantly longer than the positive subgroup.

CONCLUSION

Consideration of histologic differences and perivascular infiltration may be useful for clinical T staging of AGC.

Application of spectral CT imaging in evaluating lymph node metastasis in patients with gastric cancers: initial findings

BACKGROUND

Traditional computed tomography (CT) can predict the lymph node metastasis of gastric cancers with moderate accuracy; however, investigation of spectral CT imaging in this field is still limited.

PURPOSE

To explore the application of spectral CT imaging in evaluating lymph node metastasis in patients with gastric cancers.

MATERIAL AND METHODS

Twenty-four patients with gastric cancers prospectively underwent spectral CT imaging in the arterial phase. The short and long diameters, material concentrations, and CT values were measured and compared between lymph nodes with and without metastasis. The diagnostic performance of the CT index in identifying metastatic lymph nodes was analyzed with receiver operating characteristic (ROC) analysis.

RESULTS

A total of 102 lymph nodes (77 metastatic, 25 non-metastatic) were detected on spectral CT imaging with the reference of postoperative pathologic exanimation. The short and long diameters, water/fat concentrations, CT value, and ratio between lymph nodes vs. tumors of metastatic lymph nodes were significantly higher than those of non-metastatic ones (all P < 0.05). With a cut-off of 0.785, the CT ratio of lymph node/tumor on 70-keV monochromatic images yielded an accuracy of 81.4% in differentiating lymph nodes with and without metastasis.

CONCLUSION

Spectral CT imaging detects lymph nodes more clearly, and the CT ratio of lymph node/tumor on 70-keV monochromatic images holds great potential in differentiating lymph nodes with and without metastasis, which is more accurate than size measurement.

KIF23 Promotes Gastric Cancer by Stimulating Cell Proliferation

Gastric cancer (GC) is one of the most aggressive malignant tumors with low early diagnosis and high metastasis. Despite progress in treatment, to combat this disease, a better understanding of the underlying mechanisms and novel therapeutic targets is needed. KIF23, which belongs to the KIF family, plays a vital role in various cell processes, such as cytoplasm separation and axon elongation. Nowadays, KIF23 has been found to be highly expressed in multiple tumor tissues and cells, suggesting a potential link between KIF23 and tumorigenesis. Herein, we reported that KIF23 expression was correlated with poor prognosis of gastric cancer and found an association between KIF23 and pTNM stage. An in vitro assay proved that the proliferation of gastric cancer cells was significantly inhibited, which is caused by KIF23 depletion. Additionally, knockdown of KIF23 resulted in a marked inhibition of cell proliferation of gastric cancer in mice, with significant downregulation of Ki67 and PCNA expression. In conclusion, these data indicate that KIF23 is a potential therapeutic target for gastric cancer treatment.

Clinical significance of computed tomography-detected ascites in gastric cancer patients with peritoneal metastases

Patients with peritoneal metastases (PM) are generally considered incurable; therefore, the presence of PM is a critical factor in deciding between palliative surgery and curative resection as a therapeutic strategy. Previous studies have not determined the predictive value of ascites detected on computed tomography (CT) for the presence of PM. We aimed to analyze the factors that are associated with PM in patients with CT-detected ascites.A total of 2207 consecutive patients who were diagnosed with gastric cancer between 2004 and 2013 were identified. Eleven patients with liver cirrhosis or chronic renal insufficiency with ascites and 57 patients who received previous treatment were excluded. Ninety-eight patients who had definite evidence of distant metastasis or PM on CT and 64 patients who did not undergo surgery were excluded. A total of 91 patients were enrolled in the study to analyze the association between CT-detected ascites and surgically confirmed PM.Seventy-six patients underwent curative resection and 15 patients underwent palliative surgery. Twelve patients exhibited peritoneal seeding and 37 patients showed regional lymph node metastasis. Regional lymph node metastasis, advanced gastric cancer, undifferentiated pathology, and the amount of ascites were significantly associated with PM. Multivariable logistic regression analysis identified the amount of ascites to be an independent risk factor for the presence of PM.Regional lymph node metastasis, advanced gastric cancer, undifferentiated pathology, and the amount of ascites were associated with PM. The amount of ascites was found to be an independent risk factor for PM.

Preoperative tumor restaging and resectability assessment of gastric cancers after chemotherapy: diagnostic accuracy of MDCT using new staging criteria

PURPOSE

To evaluate the diagnostic performance of preoperative MDCT for tumor restaging and determination of resectability in gastric cancers after chemotherapy using new staging criteria.

METHODS

This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. Thirty-seven patients with initially unresectable gastric cancers who had received chemotherapy followed by surgery were included. Two independent radiologists reviewed preoperative MDCT images to determine the TNM staging and rate the overall likelihood of resectability using a 5-point scale (5: definitely unresectable, 1: definitely resectable). New post-chemotherapy MDCT criteria do not use non-enhancing perigastric infiltrations, non-enhancing lymph nodes (LNs), and subtle remaining infiltrations after marked decrease in the size of distant metastases for T, N, and M upstaging, respectively. Discrepancies in TNM staging were resolved by a third reviewer. The diagnostic performances of MDCT were assessed using pathologic results or operation records as reference standards.

RESULTS

For predicting resectability, the areas under the ROC curve were 0.885 and 0.882 (95% CIs 0.737-0.966 and 0.733-0.964) in reviewers 1 and 2, respectively, with substantial inter-reader agreement (weighted κ = 0.689). Sensitivities and specificities of MDCT for tumor restaging on a consensus review were 80.0% (4/5) and 100% (29/29) for T4b, 35.3% (6/17) and 81.3% (13/16) for N-positive, and 63.6% (7/11) and 100% (26/26) for M1, respectively.

CONCLUSIONS

For gastric cancers after chemotherapy, new MDCT criteria demonstrated high specificities for T4b and M-staging and good performances to predict resectability before conversion surgery.

Consideration of clinicopathologic features improves patient stratification for multimodal treatment of gastric cancer

Preoperative staging of gastric cancer with computed tomography alone exhibits poor diagnostic accuracy, which may lead to improper treatment decisions. We developed novel patient stratification criteria to select appropriate treatments for gastric cancer patients based on preoperative staging and clinicopathologic features. A total of 5352 consecutive patients who underwent gastrectomy for gastric cancer were evaluated. Preoperative stages were determined according to depth of invasion and nodal involvement on computed tomography. Logistic regression analysis was used to identify clinicopathological factors associated with the likelihood of proper patient stratification. The diagnostic accuracies of computed tomography scans for depth of invasion and nodal involvement were 67.1% and 74.1%, respectively. Among clinicopathologic factors, differentiated tumor histology, tumors smaller than 5 cm, and gross appearance of early gastric cancer on endoscopy were shown to be related to a more advanced stage of disease on preoperative computed tomography imaging than actual pathological stage. Additional consideration of undifferentiated histology, tumors larger than 5 cm, and grossly advanced gastric cancer on endoscopy increased the probability of selecting appropriate treatment from 75.5% to 94.4%. The addition of histology, tumor size, and endoscopic findings to preoperative staging improves patient stratification for more appropriate treatment of gastric cancer.

Beyond gastric adenocarcinoma: Multimodality assessment of common and uncommon gastric neoplasms

Despite advances in molecular biology, imaging, and treatment, gastric neoplasms remain a significant cause of morbidity and mortality; gastric adenocarcinoma is the fifth most common malignancy and third most common cause of death worldwide (Brenner et al., Methods Mol Biol 472:467-477, 2009; Howson et al. Epidemiol Rev 8:1-27, 1986; Roder, Gastric Cancer 5(Suppl 1):5-11, 2002; Ferlay et al., GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11 [Internet]. International Agency for Research on Cancer, 2013). Because of both the frequency at which malignant gastric tumors occur as well as the worldwide impact, gastric neoplasms remain important lesions to identify and characterize on all imaging modalities. Despite the varied histologies and behaviors of these neoplasms, many have similar imaging features. Nonetheless, the treatment, management, and prognosis of gastric neoplasms vary by pathology, so it is essential for the radiologist to make every effort to differentiate between these lesions and raise the less common entities as differential diagnostic considerations when appropriate.

Impact of the Cross-Sectional Location of Multidetector Computed Tomography Scans on Prediction of Serosal Exposure in Patients with Advanced Gastric Cancer

BACKGROUND

The extent of serosal exposure varies depending on the cross-section of the stomach that is viewed, affected by the visceral peritoneum of the omentum. Although multidetector computed tomography (MDCT) is the most useful method to predict serosal exposure, the MDCT criteria for such exposure by cross-sectional location remain to be established.

METHODS

The MDCT of gastric cancer patients who underwent surgery, and for whom pathological reports were available, were reviewed by radiologists. The MDCT criteria for invasion depth were divided into five grades: (1) smooth margin; (2) undulating margin; (3) streaky margin within vessels; (4) nodular margin within perigastric vessels; and (5) streaky or nodular margin over the perigastric vessels. The five grades were compared in terms of pathological tumor depth by curvature and wall group.

RESULTS

A total of 125 patients of stage ≥ T2 were enrolled. The five MDCT grades correlated with tumor depth (P < 0.001). Exposed serosal lesions of grade 3 (P = 0.031) and 5 (P = 0.030) constituted significantly the largest proportion of wall and curvature cancers, respectively. The accuracy of MDCT in terms of T staging using the five grades was calculated by cross-sectional location. The highest accuracies were associated with curvature- and wall-located tumors (55.1 and 64.3%, respectively) when serosal exposure was graded 5 and 3, respectively. The highest overall accuracy for T staging was 59.2% when the various MDCT criteria were applied by reference to the cross-sectional location.

CONCLUSIONS

The MDCT criteria for serosal exposure vary by the cross-sectional location of the gastric cancer.

Preoperative Gross Classification of Gastric Adenocarcinoma: Comparison of Double Contrast-Enhanced Ultrasound and Multi-Detector Row CT

The aim of this study was to compare the accuracy of multi-detector computed tomography (MDCT) with double contrast-enhanced ultrasound (DCEUS), in which intravenous microbubbles are used alongside oral contrast-enhanced ultrasound, in determining the gross classification of patients with gastric carcinoma (GC). Altogether, 239 patients with GC proved by histology after endoscopic biopsy were included in this study. DCEUS and MDCT were performed pre-operatively. The diagnostic accuracies of DCEUS and MDCT in determining the gross classification were calculated and compared. The overall accuracy of DCEUS in determining the gross appearance of GC was higher than that of MDCT (84.9% vs. 79.9%, p < 0.001). There was no significant difference in accuracy between DCEUS and MDCT for Borrmann I and IV classifications of advanced gastric cancer (χ(2), p = 0.323 for Borrmann type I, p = 0.141 for Borrmann type IV). The accuracy of DCEUS for early GC and Borrmann II and III classifications of GC was higher than that of MDCT (χ(2), p = 0.000 for all). DCEUS may be regarded as a valuable complementary tool to MDCT in determining the gross appearance of gastric adenocarcinoma pre-operatively.

Preoperative locoregional staging of gastric cancer: is there a place for magnetic resonance imaging? Prospective comparison with EUS and multidetector computed tomography

BACKGROUND

The aim of this study was to prospectively compare the diagnostic performance of magnetic resonance imaging (MRI), multidetector computed tomography (MDCT) and endoscopic ultrasonography (EUS) in the preoperative locoregional staging of gastric cancer.

METHODS

This study had Institutional Review Board approval, and informed consent was obtained from all patients. Fifty-two patients with biopsy-proven gastric cancer underwent preoperative 1.5-T MRI, 64-channel MDCT and EUS. All images were analysed blind, and the results were compared with histopathological findings according to the seventh edition of the TNM classification. After the population had been divided on the basis of the local invasion (T1-3 vs T4a-b) and nodal involvement (N0 vs N+), sensitivity, specificity, positive and negative predictive value, and accuracy were calculated and diagnostic performance measures were assessed using the McNemar test.

RESULTS

For T staging, EUS showed higher sensitivity (94%) than MDCT and MRI (65 and 76%; p = 0.02 and p = 0.08). MDCT and MRI had significantly higher specificity (91 and 89%) than EUS (60%) (p = 0.0009 and p = 0.003). Adding MRI to MDCT or EUS did not result in significant differences for sensitivity. For N staging, EUS showed higher sensitivity (92%) than MRI and MDCT (69 and 73%; p = 0.01 and p = 0.02). MDCT showed better specificity (81%) than EUS and MRI (58 and 73%; p = 0.03 and p = 0.15).

CONCLUSIONS

Our prospective study confirmed the leading role of EUS and MDCT in the staging of gastric cancer and did not prove, at present, the value of the clinical use of MRI.

The prediction of survival of patients with gastric cancer with PD-L1 expression using contrast-enhanced ultrasonography

Gastric cancer is the one of the most common cancers around the world. The prognosis of gastric cancer remains poor, due to the biological characteristics of the primary tumor as well as the recurrence after treatment. Accumulating evidence suggests the implication of programmed death ligand-1 (PD-L1) in the pathogenesis and prognosis of cancer. This study aimed to explore the CEUS as a valuable tool to improve the assessment of the therapeutic effect of the PD-L1 blocker in the treatment of gastric cancer. A total number of 105 patients with gastric cancer were enrolled in this study from June 2008 to December 2011 in our hospital. The association of PD-L1 expression level (105 cases) and CEUS parameters (100 cases) with the prognosis of gastric cancer was examined. The results showed that PD-L1-positive staining was associated with the depth of invasion, differentiation, and poor prognosis of patients with gastric cancer. The CEUS intensity (positive) exhibited poor prognosis compared to the negative counterpart. Moreover, PD-L1 and CEUS co-positivity was significantly related to a poor prognosis. The characteristic of ultrasonography images correlated with the expression of PD-L1 (r = 0.46, P = 0.0003). Collectively, the mean intensity of contrast-enhanced ultrasonography is a useful predictor in the PD-L1 expression in gastric cancer. The ultrasonography and CEUS parameter could be considered as the predictor of response to PD-L1 blocker treatment in the clinical practice.

High expression level of T-box transcription factor 5 predicts unfavorable survival in stage I and II gastric adenocarcinoma

The expression of T-box transcription factor 5 (TBX5) has previously been observed in human cancer. The aim of the present study was to investigate TBX5 expression and its potential clinical significance in gastric cancer (GC). Using reverse transcription-quantitative polymerase chain reaction, the TBX5 mRNA expression levels in 30 pairs of surgically resected healthy gastric tissues and early stage (stages I and II) GC tissues were evaluated. The TBX5 mRNA expression levels were increased in GC stage I and II tumor tissues (P=0.01, n=30) compared with the matched adjacent non-tumor tissue. However, no significant difference was observed in TBX5 mRNA expression levels in matched adjacent non-tumor tissue compared with the tumor tissue from stage III and IV GC samples (P=0.318, n=30). Immunohistochemical analysis for TBX5 expression was performed on 161 paraffin-embedded stage I and II GC tissue blocks. Statistical analysis was performed to evaluate the associations between TBX5 expression, clinicopathological factors and prognosis. Patients with stage I and II GC and tumors with high TBX5 expression levels presented poor overall survival (OS) rate (P=0.024). The Cox proportional hazards model analysis demonstrated that TBX5 expression was an independent risk factor (P=0.017). The present study indicates that high expression of TBX5 is associated with unfavorable OS rates in patients with stage I and II GC. In conclusion, the expression of TBX5 may be a valuable biomarker for the selection of cases of high-risk stage I and II GC.

Usefulness of Two-Dimensional Values Measured Using Preoperative Multidetector Computed Tomography in Predicting Lymph Node Metastasis of Gastric Cancer

BACKGROUND

Multidetector computed tomography (MDCT) is essential for the prediction of lymph node (LN) metastasis in gastric cancer. However, the measurement method and size criteria for metastatic LNs using MDCT are unclear.

METHODS

MDCTs of gastric cancer patients who underwent surgery and had pathological staging were reviewed by radiologists. The two-dimensional cutoff values for LNs with suspected metastasis were calculated, and clinicopathological data were analyzed using those cutoff values.

RESULTS

The total number of enrolled patients was 327. The cutoff values of the maximal area with metastatic LNs were obtained significantly at stations 3, 4, and 6, and those values were 112.09, 33.79, and 85.88 mm(2), respectively. The common cutoff value was 112.09 mm(2), and the area under the curve was 0.617 (P = 0.002). The overall survival rate of the patients with LNs less than 112.09 mm(2) was significantly better than those with LNs greater than 112.09 mm(2) (P < 0.001). In multivariate analysis, the maximal LN area was an independent prognostic factor (adjusted hazard ratio, 1.697 [95% confidence interval 1.116-2.582]).

CONCLUSIONS

Using two-dimensional values for LNs measured by MDCT is a practical method of predicting metastatic LNs in gastric cancer. The maximal LN area value would be useful in both the preoperative staging and prognosis prediction of gastric cancer.

Multidetector computed tomography in the preoperative staging of gastric adenocarcinoma

Objective

To evaluate the role of multidetector computed tomography in the preoperative investigation of tumor invasion depth and lymph node and metastatic involvement according to the TNM classification, in patients with gastric adenocarcinoma.

Materials and Methods

Fifty-four patients with biopsy-confirmed gastric cancer underwent preoperative staging with 64-channel multidetector computed tomography. Two independent radiologists analyzed the images and classified the findings. Sensitivity, specificity, accuracy and overall accuracy were calculated for each observer. The interobserver agreement was also evaluated.

Results

The accuracy in the classification of categories T ranged from 74% to 96% for observer 1 and from 80% to 92% for observer 2. The overall accuracy was 70% for both observers. The weighted kappa index was 0.75, consistent with a significant interobserver agreement. The accuracy in the classification of lymph node involvement (category N) ranged from 55% to 79% for observer 1 and from 73% to 82% for observer 2. The evaluation of metastatic involvement showed an overall accuracy of 89.6% for both observers.

Conclusion

64-channel multidetector computed tomography demonstrated clinically relevant accuracy in the preoperative staging of gastric adenocarcinoma as regards invasion depth (T category) and metastatic involvement (M category).

Upper abdominal gadoxetic acid-enhanced and diffusion-weighted MRI for the detection of gastric cancer: Comparison with two-dimensional multidetector row CT

AIM

To evaluate the diagnostic performance of abdominal magnetic resonance imaging (MRI) for the detection of gastric cancer in comparison with that of two-dimensional (2D) multidetector row computed tomography (CT).

MATERIALS AND METHODS

The study included 189 patients with 170 surgically confirmed gastric cancers and 19 patients without gastric cancer, all of whom underwent gadoxetic acid-enhanced MRI with diffusion-weighted (DW) imaging, and multidetector contrast-enhanced abdominal CT imaging. Two observers independently analysed three sets of images (CT set, conventional MRI set, and combined conventional and DW MRI set). A five-point scale for likelihood of gastric cancer was used. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were evaluated. Quantitative [apparent diffusion coefficient (ADC) analyses with Mann-Whitney U-test were conducted for gastric cancers and the nearby normal gastric wall.

RESULTS

The diagnostic accuracy and sensitivity for detection of gastric cancer were significantly higher on combined conventional and DW MRI set (77.8-78.3%; 75.3-75.9%) than the CT imaging set (67.7-71.4%; 64.1-68.2%) or the conventional MRI set (72-73%; 68.8-70%; p < 0.01). In particular, for gastric cancers with pT2 and pT3, the combined conventional and DW MRI set (91.6-92.6%) yielded significantly higher sensitivity for detection of gastric cancer than did the CT imaging set (76.8-81.1%) by both observers (p < 0.01). The mean ADC of gastric cancer lesions (1 ± 0.23 × 10(-3) mm(2)/s) differed significantly from that of normal gastric wall (1.77 ± 0.25 × 10(-3) mm(2)/s; p < 0.01).

CONCLUSION

Abdominal MRI with DW imaging was more sensitive for the detection of gastric cancer than 2D-multidetector row CT or conventional MRI alone.

State-of-the-art preoperative staging of gastric cancer by MDCT and magnetic resonance imaging

Gastric cancer is one of the most common and fatal cancers. The importance of accurate staging for gastric cancer has become more critical due to the recent introduction of less invasive treatment options, such as endoscopic mucosal resection or laparoscopic surgery. The tumor-node-metastasis staging system is the generally accepted staging system for predicting the prognosis of patients with gastric cancer. Multidetector row computed tomography (MDCT) is a widely accepted imaging modality for the preoperative staging of gastric cancer that can simultaneously assess locoregional staging, including the gastric mass, regional lymph nodes, and distant metastasis. The diagnostic performance of MDCT for T- and N-staging has been improved by the technical development of isotropic imaging and 3D reformation. Although magnetic resonance imaging (MRI) was not previously used to evaluate gastric cancer due to the modality’s limitations, the development of high-speed sequences has made MRI a feasible tool for the staging of gastric cancer.

Prospective comparison of 3T MRI with diffusion-weighted imaging and MDCT for the preoperative TNM staging of gastric cancer

PURPOSE

To compare the diagnostic performance of 3T magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) and multidetector-row computed tomography (MDCT) for the preoperative TNM staging of gastric cancer.

MATERIALS AND METHODS

This prospective study was approved by our Institutional Review Board. Forty-nine consecutive patients with histologically confirmed gastric cancers underwent MDCT and 3T MRI followed by surgery. MRI without DWI, MRI with DWI, and MDCT were reviewed to determine preoperative TNM staging. Using the pathologic stages as the reference standard, the diagnostic performance of each imaging modality was compared.

RESULTS

Diagnostic accuracies of MRI with DWI, MRI without DWI, and MDCT did not show a significant difference (≤T2 vs. ≥T3: 85.1%, 78.7%, and 80.9%; ≤T3 vs. T4: 76.6%, 74.5%, and 72.3%; N-negative vs. N-positive: 76.6%, 66.0%, and 63.8%; M0 vs. M1: all 95.9%, respectively) (P > 0.05). For N staging, MRI with DWI demonstrated higher sensitivity but lower specificity (86.7% and 58.8%, respectively) than MRI without DWI (50.0% and 94.1%) or MDCT (43.3% and 100%) (P < 0.05).

CONCLUSION

The diagnostic accuracy of 3T MRI is comparable to that of MDCT for the preoperative TNM staging of gastric cancer, and for assessing LN metastasis, the addition of DWI to conventional MRI may increase the sensitivity.

Double contrast-enhanced ultrasonography in preoperative Borrmann classification of advanced gastric carcinoma: comparison with histopathology

The purpose of this study was to investigate the accuracy of double contrast-enhanced ultrasonography (DCEUS) for assessing the Borrmann classification of advanced gastric carcinoma (AGC) preoperatively. Three hundred twenty nine patients with proved AGC were enrolled. DCEUS (intravenous microbubbles combined with combined with oral contrast-enhanced ultrasound) was performed preoperatively. The diagnostic accuracy of DCEUS in determining Borrmann classification was compared with postoperative pathological findings. The reliability of DCEUS was analyzed. The accuracy of DCEUS in determining the Borrmann classification of AGC was 91.49%. The intra- and inter-observer reproducibility was both almost perfect for assessing the Borrmann classification of AGC by DCEUS. DCEUS could be considered as an accurate, non-invasive, and reliable diagnostic method for preoperative Borrmann classification of advanced gastric carcinoma.

Application value of multi-slice spiral computed tomography for imaging determination of metastatic lymph nodes of gastric cancer

AIM: To evaluate the application value of multi-slice spiral computed tomography (MSCT) for imaging determination of metastatic lymph nodes of gastric cancer and to explore reasonable diagnostic criteria.

METHODS: Sixty patients with gastric cancer underwent 64 MSCT scans before operation. Gastric cancer samples and perigastric lymph nodes were obtained after operation, formalin fixation and haematoxylin-eosin staining. The metastatic conditions of gastric cancer and perigastric lymph nodes were determined under a light microscope. A total of 605 lymph nodes were grouped and assessed according to distribution, size, shape and degree of lymph node enhancement. Then, the findings were compared with the postoperative pathological results.

RESULTS: Among 605 lymph nodes, 358 were confirmed as metastatic, accounting for 59.2%. A total of 535 lymph nodes were detected in original axis images combined with multiplanar reconstruction images of MSCT. The metastatic lymph nodes had specific signs in computed tomography. This study showed that the long diameter of lymph nodes ≥ 8 mm indicated metastasis; the sensitivity and specificity were 79.6% and 78.8%, respectively. The difference of the mean value of lymph node enhancement density ≥ 80 Hu indicated metastasis; the sensitivity and specificity were 81.6% and 75.6%, respectively. The ratio of short diameter to long diameter of lymph nodes ≥ 0.7 indicated metastasis; the sensitivity and specificity were 85.6% and 71.8%, respectively.

CONCLUSION: MSCT is a non-invasive and reliable method for preoperative examination of gastric cancer. Sensitivity and specificity for prediction of lymph node metastasis are high.

Enhancement patterns of gastric carcinoma on contrast-enhanced ultrasonography: relationship with clinicopathological features

The aim of this study was to assess the relationship between the enhancement patterns and clinicopathological features of gastric cancer using intravenous contrast-enhanced ultrasonography (CEUS). In this Ethics Committee-approved prospective study, five hundred fifty two patients with gastric cancer who gave informed consent were examined preoperatively with CEUS. The enhancement pattern of each tumor was analyzed visually. Gross and histopathological findings on the postoperative specimens were compared with the preoperative CEUS findings. The most common CEUS pattern in differentiated gastric cancer was homogeneous enhancement, whereas heterogeneous enhancement was the most common pattern in undifferentiated gastric cancer. The proportion of heterogeneous enhancement was significantly different between the two histological subtypes (Chi- square = 146.735, P<0.001). The sensitivity and specificity of early heterogeneous enhancement on CEUS in diagnosing undifferentiated gastric cancer were 78.84% and 72.59% respectively. Gastric cancers with heterogeneous enhancement were more often Borrmann III and IV macroscopic types than those with homogeneous enhancement (66.56% vs. 30.80%, P<0.001), more commonly T3 and T4 depth of invasion than those with homogeneous enhancement (71.52% vs. 59.60%, P<0.05), more often showed lymphatic invasion than those with homogeneous enhancement (84.44% vs. 76.40%, P<0.05), and were less likely to receive curative gastrectomy than those with homogeneous enhancement (74.83% vs. 86.40%, P<0.005). The intra- and inter-observer reproducibility were both almost perfect for assessing enhancement patterns, with Kappa values of 0.916 (P<0.001) for intra-observer and 0.842 (P<0.001) for inter-observer reproducibility. CEUS provided detailed information about tumor vascularity and contrast enhancement patterns in gastric cancer. CEUS is promising as a new and useful method to predict the histological type of gastric cancer.

MDCT features in the differentiation of T4a gastric cancer from less-advanced gastric cancer: significance of the hyperattenuating serosa sign

OBJECTIVE

The purpose of our study was to evaluate CT findings to differentiate between T4a and less advanced gastric cancers.

METHODS

The institutional review board approved this study and waived informed consent. This study included 228 retrospectively identified patients with surgically confirmed gastric cancer (138 T1, 25 T2, 24 T3 and 41 T4a) and who had also undergone pre-operative CT scan. Transverse and multiplanar reconstruction scans were reviewed in consensus by two other blinded radiologists. The following CT findings that differentiate T4a from less advanced cancers were evaluated: nodular or an irregular outer layer of the gastric wall, haziness of the perigastric fat and a hyperattenuating serosa sign. The CT features of T4a and less advanced gastric cancers were compared by means of univariate and multivariate analyses.

RESULTS

In univariate analysis, nodular or an irregular outer layer of the gastric wall, haziness of the perigastric fat and the hyperattenuating serosa sign were significant in differentiation between T4a and less advanced gastric cancers. In addition, nodular or an irregular outer layer of the gastric wall and the hyperattenuating serosa sign were significant in differentiation between T3 and T4a. In multivariate logistic analysis, the hyperattenuating serosa sign was the most significant finding in differentiation between T3 and T4a (odds ratio, 4.210; 95% confidence intervals, 1.581-11.214; p=0.004).

CONCLUSION

The hyperattenuating serosa sign may be a useful CT finding in differentiation between T4a and less-advanced gastric cancers.

ADVANCES IN KNOWLEDGE

The hyperattenuating serosa sign is associated with gastric cancer with invading the serosa and can facilitate planning of the optimal pre-operative evaluation and treatment.

Gastric cancer staging with radiologic imaging modalities and UICC staging system

There are two major stage classification systems for gastric cancer: the tumor-node-metastasis (TNM) stages by the International Union against Cancer (UICC) and the Japanese Classification of Gastric Carcinoma by the Japanese Gastric Cancer Association (JGCA). Preoperative stage classification using either of these systems is essential for deciding on the treatment strategy in the era of various multimodal therapeutic options. Evolution of multidetector computerized tomography with isotropic volumetric imaging and various 3D images has increased the accuracy of T and N staging in patients with gastric cancer, although detection of peritoneal deposits and nodal metastasis in the absence of lymphadenopathy remain problematic with the imaging tools currently available. The TNM and JGCA classifications have undergone revisions independent of each other, and the discrepancies were not helpful when international comparisons and cooperation were needed. More recently, the JGCA and TNM classifications were merged to have identical T and N categories, in addition to the more straightforward M categories that indicate the presence of distant metastasis. The result of these efforts is that researchers in Japan and the rest of the world are now looking at a similar disease when they discuss cancer that belongs to the same stage. A nomogram that incorporates other established prognostic determinants in addition to the TNM component may be a future direction for a more sophisticated means of predicting outcome. The increasing incidence of junctional (esophagogastric junction) cancer in the Far East has spurred researchers from this region to adequately stage the disease and to consider suitable treatment modalities for this disease entity, whereas Western researchers are more inclined to treat this disease as esophageal cancer. This could be an area for future international debate. For the next more accurate staging, we suggest the collaboration between Eastern and Western high-volume centers in gastric cancer because the inconsistency of surgical approaches, especially with respect to nodal resection, remains a barrier to mutual understanding.

Using the K-nearest neighbor algorithm for the classification of lymph node metastasis in gastric cancer

Accurate tumor, node, and metastasis (TNM) staging, especially N staging in gastric cancer or the metastasis on lymph node diagnosis, is a popular issue in clinical medical image analysis in which gemstone spectral imaging (GSI) can provide more information to doctors than conventional computed tomography (CT) does. In this paper, we apply machine learning methods on the GSI analysis of lymph node metastasis in gastric cancer. First, we use some feature selection or metric learning methods to reduce data dimension and feature space. We then employ the K-nearest neighbor classifier to distinguish lymph node metastasis from nonlymph node metastasis. The experiment involved 38 lymph node samples in gastric cancer, showing an overall accuracy of 96.33%. Compared with that of traditional diagnostic methods, such as helical CT (sensitivity 75.2% and specificity 41.8%) and multidetector computed tomography (82.09%), the diagnostic accuracy of lymph node metastasis is high. GSI-CT can then be the optimal choice for the preoperative diagnosis of patients with gastric cancer in the N staging.