Preoperative T staging of gastric cancer by multi-detector row computed tomography

Application of spectral CT in diagnosis, classification and prognostic monitoring of gastrointestinal cancers: progress, limitations and prospects

Gastrointestinal (GI) cancer is the leading cause of cancer-related deaths worldwide. Computed tomography (CT) is an important auxiliary tool for the diagnosis, evaluation, and prognosis prediction of gastrointestinal tumors. Spectral CT is another major CT revolution after spiral CT and multidetector CT. Compared to traditional CT which only provides single-parameter anatomical diagnostic mode imaging, spectral CT can achieve multi-parameter imaging and provide a wealth of image information to optimize disease diagnosis. In recent years, with the rapid development and application of spectral CT, more and more studies on the application of spectral CT in the characterization of GI tumors have been published. For this review, we obtained a substantial volume of literature, focusing on spectral CT imaging of gastrointestinal cancers, including esophageal, stomach, colorectal, liver, and pancreatic cancers. We found that spectral CT can not only accurately stage gastrointestinal tumors before operation but also distinguish benign and malignant GI tumors with improved image quality, and effectively evaluate the therapeutic response and prognosis of the lesions. In addition, this paper also discusses the limitations and prospects of using spectral CT in GI cancer diagnosis and treatment.

The Role of Staging Laparoscopy for Gastric Cancer Patients: Current Evidence and Future Perspectives

A significant proportion of patients diagnosed with gastric cancer is discovered with peritoneal metastases at laparotomy. Despite the continuous improvement in the performance of radiological imaging, the preoperative recognition of such an advanced disease is still challenging during the diagnostic work-up, since the sensitivity of CT scans to peritoneal carcinomatosis is not always adequate. Staging laparoscopy offers the chance to significantly increase the rate of promptly diagnosed peritoneal metastases, thus reducing the number of unnecessary laparotomies and modifying the initial treatment strategy of gastric cancer. The aim of this review was to provide a comprehensive summary of the current literature regarding the role of staging laparoscopy in the management of gastric cancer. Indications, techniques, accuracy, advantages, and limitations of staging laparoscopy and peritoneal cytology were discussed. Furthermore, a focus on current evidence regarding the application of artificial intelligence and image-guided surgery in staging laparoscopy was included in order to provide a picture of the future perspectives of this technique and its integration with modern tools in the preoperative management of gastric cancer.

Prospective Comparison of Oral Contrast-Enhanced Transabdominal Ultrasound Imaging With Contrast-Enhanced Computed Tomography in Pre-operative Tumor Staging of Gastric Cancer

The aim of this prospective study was to compare the diagnostic accuracy of oral contrast-enhanced transabdominal ultrasound imaging (OCTU) with that of contrast-enhanced computed tomography (CT) for the pre-operative tumor staging of gastric cancer, with post-operative pathology as the standard. We included 108 cases of gastric cancer with simultaneous OCTU and enhanced CT pre-operative tumor staging diagnoses. Results were compared with post-operative pathology based on the eighth edition of the American Joint Committee on Cancer tumor-node-metastasis staging guidelines for gastric cancer. The accuracy of each tumor stage was obtained by comparing OCTU and enhanced CT diagnoses with post-operative pathology. The McNemar test was used to compare the overall accuracy of the two methods. There was no statistical difference in accuracy between OCTU (72.2%) and enhanced CT (75.9%, p = 0.644) for overall pre-operative tumor staging diagnosis. For stages T1 to T4, the accuracy rates of OCTU were 84.2%, 81.8%, 69.4% and 65.5%, respectively, and those for enhanced CT were 52.6%, 72.7%, 87.8% and 72.4%, respectively. OCTU is comparable to enhanced CT in the preoperative overall T-stage diagnosis of gastric cancer.

Added Value of the Sliding Sign on Right Down Decubitus CT for Determining Adjacent Organ Invasion in Patients with Advanced Gastric Cancer

Purpose

To investigate the added value of right down decubitus (RDD) CT when determining adjacent organ invasion in cases of advanced gastric cancer (AGC).

Materials and Methods

A total of 728 patients with pathologically confirmed T4a (pT4a), surgically confirmed T4b (sT4b), or pathologically confirmed T4b (pT4b) AGCs who underwent dedicated stomach-protocol CT, including imaging of the left posterior oblique (LPO) and RDD positions, were included in this study. Two radiologists scored the T stage of AGCs using a 5-point scale on LPO CT with and without RDD CT at 2-week intervals and recorded the presence of "sliding sign" in the tumors and adjacent organs and compared its incidence of appearance.

Results

A total of 564 patients (77.4%) were diagnosed with pT4a, whereas 65 (8.9%) and 99 (13.6%) patients were diagnosed with pT4b and sT4b, respectively. When RDD CT was performed additionally, both reviewers deemed that the area under the curve (AUC) for differentiating T4b from T4a increased (p < 0.001). According to both reviewers, the AUC for differentiating T4b with pancreatic invasion from T4a increased in the subgroup analysis (p < 0.050). Interobserver agreement improved from fair to moderate (weighted kappa value, 0.296-0.444).

Conclusion

RDD CT provides additional value compared to LPO CT images alone for determining adjacent organ invasion in patients with AGC due to their increased AUC values and improved interobserver agreement.

Development of the PERI-Gastric (PEritoneal Recurrence Index) and PERI-Gram (Peritoneal Recurrence Index NomoGRAM) for predicting the risk of metachronous peritoneal carcinomatosis after gastrectomy with curative intent for gastric cancer

BACKGROUND

A model that quantifies the risk of peritoneal recurrence would be a useful tool for improving decision-making in patients undergoing curative-aim gastrectomy for gastric cancer (GC).

METHODS

Five Italian centers participated in this study. Two risk scores were created according to the two most widely used pathologic classifications of GC (the Lauren classification and the presence of signet-ring-cell features). The risk scores (the PERI-Gastric 1 and 2) were based on the results of multivariable logistic regressions and presented as nomograms (the PERI-Gram 1 and 2). Discrimination was assessed with the area under the curve (AUC) of receiver operating curves. Calibration graphs were constructed by plotting the actual versus the predicted rate of peritoneal recurrence. Internal validation was performed with a bootstrap resampling method (1000 iterations).

RESULTS

The models were developed based on a population of 645 patients (selected from 1580 patients treated from 1998 to 2018). In the PERI-Gastric 1, significant variables were linitis plastica, stump GC, pT3-4, pN2-3 and the Lauren diffuse histotype, while in the PERI-Gastric 2, significant variables were linitis plastica, stump GC, pT3-4, pN2-3 and the presence of signet-ring cells. The AUC was 0,828 (0.778-0.877) for the PERI-Gastric 1 and 0,805 (0.755-0.855) for the PERI-Gastric 2. After bootstrap resampling, the PERI-Gastric 1 had a mean AUC of 0.775 (0.721-0.830) and a 95%CI estimate for the calibration slope of 0.852-1.505 and the PERI-Gastric 2 a mean AUC of 0.749 (0.693-0.805) and a 95%CI estimate for the slope of 0.777-1.351. The models are available at www.perigastric.org .

CONCLUSIONS

We developed the PERI-Gastric and the PERI-Gram as instruments to determine the risk of peritoneal recurrence after curative-aim gastrectomy. These models could direct the administration of prophylactic intraperitoneal treatments.

Lymph Node Response to Neoadjuvant Chemotherapy as an Independent Prognostic Factor in Metastatic Esophageal Cancer

OBJECTIVE

The aim of this study was to evaluate primary tumor (PT) and lymph node (LN) responses to neoadjuvant chemotherapy (NACT) for predicting long-term survival in patients with metastatic esophageal cancer (EC).

BACKGROUND

In evaluating NACT responses in patients with EC, imaging modalities typically target the PT in the esophagus, which is unmeasurable. Targeting measurable organs, like positive LNs, might provide more accurate assessments.

METHODS

We enrolled 251 patients with EC and clinically positive LNs that underwent curative resections, after triplet NACT. The percent reduction of PT area was measured with bidimensional computed tomography. The LN response was defined as the percent reduction of the sum of the short diameters in all positive LNs.

RESULTS

NACT reduced PTs and LNs by (median, range) 58.0% (38.1-94.9) and 34.5% (46.2-68.2), respectively. Based on the receiver-operating characteristic analyses for predicting a histological response and a 10% stepwise cutoff analyses of recurrence-free survival (RFS), responder/nonresponder cutoff values were ≥60% for PT area reductions and ≥30% for LN size reductions. 39.6% of patients showed discordant PT and LN responses. Compared with PT-responders, LN-responders had significantly less advanced pN (P < 0.0001) and pM (P = 0.015) in addition to less advanced pT (P < 0.0001) and better histological responses (P < 0.0001), and closer correlations to lymphatic, distant metastases and dissemination. A multivariate analysis of RFS identified 2 independent prognostic factors: the LN response [hazard ratio (HR) = 2.51, 95% confidence interval (CI) = 1.63-3.95, P < 0.0001] and the pN (HR = 2.72, 95% CI = 1.44-5.64, P = 0.0016), but not the PT response.

CONCLUSIONS

The LN response to NACT predicted long-term survival more precisely than the PT response in patients with metastatic EC.

Clinical TNM staging for esophageal, gastric, and colorectal cancers in the era of neoadjuvant therapy: A systematic review of the literature

AIM

Clinical staging is vital for selecting appropriate candidates and designing neoadjuvant treatment strategies for advanced tumors. The aim of this review was to evaluate diagnostic abilities of clinical TNM staging for gastrointestinal, gastrointestinal cancers.

METHODS

We conducted a systematic review of recent publications to evaluate the accuracy of diagnostic modalities on gastrointestinal cancers. A systematic literature search was performed in PubMed/MEDLINE using the keywords "TNM staging," "T4 staging," "distant metastases," "esophageal cancer," "gastric cancer," and "colorectal cancer," and the search terms used in Cochrane Reviews between January 2005 to July 2020. Articles focusing on preoperative diagnosis of: (a) depth of invasion; (b) lymph node metastases; and (c) distant metastases were selected.

RESULTS

After a full-text search, a final set of 55 studies (17 esophageal cancer studies, 26 gastric cancer studies, and 12 colorectal cancer studies) were used to evaluate the accuracy of clinical TNM staging. Positron emission tomography-computed tomography (PET-CT) and/or magnetic resonance imaging (MRI) were the best modalities to assess distant metastases. Fat and fiber mode of CT may be useful for T4 staging of esophageal cancer, CT was a partially reliable modality for lymph node staging in gastric cancer, and CT combined with MRI was the most reliable modality for liver metastases from colorectal cancer.

CONCLUSION

The most reliable diagnostic modality differed among gastrointestinal cancers depending on the type of cancer. Therefore, we propose diagnostic algorithms for clinical staging for each type of cancer.

Establishment of Decision Rules and Risk Assessment Model for Preoperative Prediction of Lymph Node Metastasis in Gastric Cancer

Background: Preoperative accurate prediction of lymph node status is especially important for the formulation of treatment plans for patients with gastric cancer (GC). The purpose of this study was to establish decision rules and a risk assessment model for lymph node metastasis (LNM) in GC using preoperative indicators. Methods: The clinical data of 554 patients who underwent gastrectomy with D2 lymphadenectomy were collected. A 1:1 propensity score matching (PSM) system was used, and the clinical data of the matched 466 patients were further analyzed. The important risk factors for LNM were extracted by the random forest algorithm, and decision rules and nomogram models for LNM were constructed with a classification tree and the "rms" package of R software, respectively. Results: Tumor size (OR: 2.058; P = 0.000), computed tomography (CT) findings (OR: 1.969; P = 0.001), grade (OR: 0.479; P = 0.000), hemoglobin (Hb) (OR: 1.211; P = 0.005), CEA (OR: 1.111; P = 0.017), and CA19-9 (OR: 1.040; P = 0.033) were independent risk factors for LNM in GC. Tumor size did rank first in the ranking of important factors for LNM in GC and was the first-level segmentation of the two initial branches of the classification tree. The accuracy, sensitivity, specificity, and positive predictive value of the decision rules in diagnosing preoperative LNM in GC were 75.6, 85.7, 73.9, 73.5, and 79.3%, respectively. The accuracy, sensitivity, and specificity of the risk assessment model in predicting preoperative LNM in GC were 79.3, 80.3, and 79.4%, respectively. Conclusion: Tumor size was the most important factor for evaluating LNM in GC. This decision rules and nomogram model constructed to take into account tumor size, CT findings, grade, hemoglobin, CEA, and CA19-9 effectively predicted the incidence of LNM in preoperative GC.

Machine Learning-Based Computational Models Derived From Large-Scale Radiographic-Radiomic Images Can Help Predict Adverse Histopathological Status of Gastric Cancer

INTRODUCTION

Adverse histopathological status (AHS) decreases outcomes of gastric cancer (GC). With the lack of a single factor with great reliability to preoperatively predict AHS, we developed a computational approach by integrating large-scale imaging factors, especially radiomic features at contrast-enhanced computed tomography, to predict AHS and clinical outcomes of patients with GC.

METHODS

Five hundred fifty-four patients with GC (370 training and 184 test) undergoing gastrectomy were retrospectively included. Six radiomic scores (R-scores) related to pT stage, pN stage, Lauren & Borrmann (L&B) classification, World Health Organization grade, lymphatic vascular infiltration, and an overall histopathologic score (H-score) were, respectively, built from 7,000+ radiomic features. R-scores and radiographic factors were then integrated into prediction models to assess AHS. The developed AHS-based Cox model was compared with the American Joint Committee on Cancer (AJCC) eighth stage model for predicting survival outcomes.

RESULTS

Radiomics related to tumor gray-level intensity, size, and inhomogeneity were top-ranked features for AHS. R-scores constructed from those features reflected significant difference between AHS-absent and AHS-present groups (P < 0.001). Regression analysis identified 5 independent predictors for pT and pN stages, 2 predictors for Lauren & Borrmann classification, World Health Organization grade, and lymphatic vascular infiltration, and 3 predictors for H-score, respectively. Area under the curve of models using those predictors was training/test 0.93/0.94, 0.85/0.83, 0.63/0.59, 0.66/0.63, 0.71/0.69, and 0.84/0.77, respectively. The AHS-based Cox model produced higher area under the curve than the eighth AJCC staging model for predicting survival outcomes. Furthermore, adding AHS-based scores to the eighth AJCC staging model enabled better net benefits for disease outcome stratification.

DISCUSSION

The developed computational approach demonstrates good performance for successfully decoding AHS of GC and preoperatively predicting disease clinical outcomes.

The role of MRI in the diagnosis and treatment of gastric cancer

Gastric cancer is the fifth most common malignancies and the third leading cause of cancer-related death worldwide, with more than 40% of new cases occurring in China. With the advancement of treatment methods, the application of adjuvant therapy and targeted drugs, the prognosis of patients with gastric cancer has been significantly improved. In recent years, more and more studies have reported that magnetic resonance imaging (MRI) showed great value in the clinical application among patients with gastric cancer, including preoperative staging, treatment response evaluation, predicting prognosis and histopathological features, treatment guidance, and molecular imaging. The remarkable research progress of MRI in gastric cancer will provide new evaluation and treatment approaches for clinical diagnosis and treatment. This article aims to review the current status of the application and research progress of MRI in patients with gastric cancer.

Risk factors and prognosis of bone metastases in newly diagnosed gastric cancer

Aim: To predict the occurrence of bone metastases and prognosis among patients with gastric cancer on a population level. Materials & methods: Data were obtained from the SEER database (2010-2016). Multivariable logistic regression and multivariable Cox regression were used to determine factors that predict the occurrence of bone metastasis and prognosis. Results: Cardia cancer, younger age, white race, poor differentiation grade, higher N stage, diffuse-type were positively associated with the presence of bone metastasis. For gastric cancer patients with bone metastasis, the median survival time was longer (9.0 months) among patients with surgery of primary site compared with those without surgery (3.0 months). Conclusion: According to the results of risk assessment, clinical efforts should be targeted to focus on screening high-risk patients.

Consensus statement of the Hellenic and Cypriot Gastric Cancer Study Group on the diagnosis, staging and management of gastric cancer

Gastric Cancer epidemics have changed over recent decades, declining in incidence, shifting from distal to proximal location, transforming from intestinal to diffuse histology. Novel chemotherapeutic agents combined with modern surgical operations hardly changed overall disease related survival. This may be attributed to a substantial inherent geographical variation of disease genetics, but also to a failure to standardize and implement treatment protocols in clinical practice. To overcome these drawbacks in Greece and Cyprus, a Gastric Cancer Study Group under the auspices of the Hellenic Society of Medical Oncology (HeSMO) and Gastrointestinal Cancer Study Group (GIC-SG) merged their efforts to produce a consensus considering ethnic parameters of healthcare system and the international proposals as well. Utilizing structured meetings of experts, a consensus was reached. To achieve further consensus, statements were subjected to the Delphi methodology by invited multidisciplinary national and international experts. Sentences were considered of high or low consensus if they were voted by ≥ 80%, or < 80%, respectively; those obtaining a low consensus level after both voting rounds were rejected. Forty-five statements were developed and voted by 71 experts. The median rate of abstention per statement was 9.9% (range: 0-53.5%). At the end of the process, one statement was rejected, another revised, and all the remaining achieved a high consensus. Forty-four recommendations covering all aspects of the management of gastric cancer and concise treatment algorithms are proposed by the Hellenic and Cypriot Gastric Cancer Study Group. The importance of centralization, care by a multidisciplinary team, adherence to guidelines, and individualization are emphasized.

Performance of a machine learning-based decision model to help clinicians decide the extent of lymphadenectomy (D1 vs. D2) in gastric cancer before surgical resection

BACKGROUND

Controversy still exists on the optimal surgical resection for potentially curable gastric cancer (GC). Use of radiologic evaluation and machine learning algorithms might predict extent of lymphadenectomy to limit unnecessary surgical treatment. We purposed to design a machine learning-based clinical decision-support model for predicting extent of lymphadenectomy (D1 vs. D2) in local advanced GC.

METHODS

Clinicoradiologic features available from routine clinical assignments in 557 patients with GCs were retrospectively interpreted by an expert panel blinded to all histopathologic information. All patients underwent surgery using standard D2 resection. Decision models were developed with a logistic regression (LR), support vector machine (SVM) and auto-encoder (AE) algorithm in 371 training and tested in 186 test data, respectively. The primary end point was to measure diagnostic performance of decision model and a Japanese gastric cancer treatment guideline version 4th (JPN 4th) criteria for discriminate D1 (pT1 + pN0) versus D2 (≥ pT1 + ≥ pN1) lymphadenectomy.

RESULTS

The decision model with AE analysis produced highest area under ROC curve (train: 0.965, 95% confidence interval (CI) 0.948-0.978; test: 0.946, 95% CI 0.925-0.978), followed by SVM (train: 0.925, 95% CI 0.902-0.944; test: 0.942, 95% CI 0.922-0.973) and LR (train: 0.886, 95% CI 0.858-0.910; test: 0.891, 95% CI 0.891-0.952). By this improvement, overtreatment was reduced from 21.7% (121/557) by treat-all pattern, to 15.1% (84/557) by JPN 4th criteria, and to 0.7-0.9% (4-5/557) by the new approach.

CONCLUSIONS

The decision model with machine learning analysis demonstrates high accuracy for identifying patients who are candidates for D1 versus D2 resection. Its approximate 14-20% improvements in overtreatment compared to treat-all pattern and JPN 4th criteria potentially increase the number of patients with local advanced GCs who can safely avoid unnecessary lymphadenectomy.

Liver Metastases in Newly Diagnosed Gastric Cancer: A Population-Based Study from SEER

Purpose: Population-based data on the proportion and prognosis of liver metastases at diagnosis of gastric cancer are currently lacking. Besides, the treatment of gastric cancer with liver metastases is still controversial now.

Methods: Patients with gastric cancer and liver metastases (GCLM) at the time of diagnosis in advanced gastric cancer were identified using the Surveillance, Epidemiology, and End Result (SEER) database of the National Cancer Institute. Multivariable logistic and Cox regression were performed to identify predictors of the presence of GCLM at diagnosis and factors associated with all-cause mortality.

Results: We identified 3507 patients with gastric cancer and liver metastases at the time of diagnosis, representing 16.89% of the entire cohort and 44.12% of the subset with metastatic disease to any distant site. Among entire cohort, multivariable logistic regression identified thirteen factors (age, race, sex, original, tumor location, pathology grade, Lauren classification, T staging, N staging, tumor size, number of extrahepatic metastatic sites to bone, lung, and brain, insurance situation and smoking) as predictors of the presence of liver metastases at diagnosis. Median survival among the entire cohort with GCLM was 4.0 months (interquartile range: 1.0-10.0 mo). Patients receiving comprehensive therapy had longer median overall survival, of which the median survival was 12.0 months (interquartile range: 6.0-31.0 mo). Multivariable Cox model in SEER cohort confirmed nine factors (age, tumor location, Lauren classification, T staging, number of extrahepatic metastatic sites to bone, lung, and brain, surgery, chemotherapy, RSC and marital status) as independent predictors for overall survival.

Conclusions: The findings of this study provided population-based estimates of the proportion and prognosis for LM at time of GC diagnosis. These findings provide preventive guidelines for screening and treatment of LM in GC patients.

Preoperative T staging of colon cancer using CT colonography with multiplanar reconstruction: new diagnostic criteria based on "bordering vessels"

PURPOSE

Preoperative T staging of colon cancer, in particular, for distinguishing T3 from T2 and T4, has been a challenge. The aim of this study was to evaluate newly developed criteria for preoperative T staging of colorectal cancer using computed tomography colonography (CTC) with multiplanar reconstruction (MPR), based on the spatial relationship of tumors and "bordering vessels," that is, marginal vessels that are detectable by multi-detector row CT with MPR.

METHODS

A total of 172 patients with colon and upper rectal cancer who underwent preoperative CTC and surgery between August 2011 and September 2013 were included. Preoperative T staging using the new criteria was performed prospectively and compared with pathologic results.

RESULTS

Sensitivity, specificity, and accuracy of T staging by CTC using the new criteria were 63%, 80%, and 77% for T2 (n = 30); 72%, 94%, and 81% for T3 (n = 95); and 79%, 99%, and 97% for T4a (n = 14), respectively. Positive predictive value for T3 was 93%, indicating that a T3 diagnosis by CTC is precise. In addition, negative predictive value for pathological T4a was 98%, indicating that a "not T4a" diagnosis by CTC is also precise.

CONCLUSIONS

Our newly developed criteria are useful for preoperative T staging, particularly for distinguishing T3 from T2 and T4.

T and N Staging of Gastric Cancer Using Dual-Source Computed Tomography

Aim

This study is aimed at comparing gastric cancer T and N staging between virtual monochromatic energy images and fusion images generated by dual-source computed tomography (DSCT) dual-energy mode data acquisition prospectively while measuring the iodine concentration of gastric cancer and lymph nodes at different T and N stages from iodine map retrospectively.

Methods

A total of 71 patients (50 males and 21 females; mean age: 59 ± 11 years) confirmed with gastric cancer by endoscopic biopsy with no neoadjuvant chemotherapy were enrolled for the CT examination before surgeries. The preoperative T and N staging results were compared between groups with pathological results as the gold standard. The iodine concentrations of the gastric lesions and LNs were measured on the iodine-based material decomposition images. All iodine concentration values were normalized against those in the abdominal aorta and defined as normalized iodine concentration (nIC) values. The short axis length of LNs and nIC values were statistically analyzed.

Results

Group A was better than group B for T3 and T4 staging. No statistically significant difference in the overall accuracies for N staging was found between groups. For the late arterial and delayed phases, T3 and T4 nIC values of the extraserosal adipose tissue showed statistically significant differences. The nIC values between N0 and Nm (N1-N3) showed statistically significant differences in the portal phase only.

Conclusions

T3 and T4 nIC values of the extraserosal adipose tissue showed statistically significant differences. Hence, dual-source CT may be helpful in the differential diagnosis between T3 and T4.

Value of multi-slice spiral computed tomography in the diagnosis of metastatic lymph nodes and N-stage of gastric cancer

Objective

To establish new diagnostic criteria for improvement of the accuracy of multi-slice spiral computed tomography (MSCT) in diagnosing the N-stage and lymph node (LN) metastasis of gastric cancer (GC).

Methods

MSCT was performed with plain and triphasic dynamic contrast enhancement. Different regions of LN metastasis and N-staging were determined according to the herein-proposed combined diagnostic criteria and were then correlated with the pathological analysis. The Kappa consistency test was used to study the accuracy of MSCT.

Results

The accuracy of MSCT in diagnosing the N-stage as a whole was 86.3%, and that in diagnosing LN metastasis was 79.1% to 98.9%. The Kappa values for stages N0, N1, and N3 ranged from 0.449 to 0.662, indicating good consistency in diagnosing these three stages between MSCT and the postsurgical pathological results. The K_total value was 0.567 between MSCT and the postsurgical pathological results in diagnosing LN metastasis. The risk of LN metastasis increased with the progression of lesion infiltrates.

Conclusions

Application of the combined diagnostic criteria increased the diagnostic performance of MSCT in not only judging the N-stage but also diagnosing LN metastasis. This study will provide valuable reference data for surgical planning for patients with GC in the clinical setting.

Dual Energy Spectral CT Imaging in the assessment of Gastric Cancer and cell proliferation: A Preliminary Study

Gastric cancer is one of the main diseases leading to cancer-related death. The recently introduced dual-energy spectral CT (DEsCT), allows to obtain many quantitative measurements from iodine-based material decomposition (MD) images, which contribute to improve the accuracy of staging of GC comparing to multidetector spiral CT. And Ki-67 is a well-recognized nuclear antigen-specific biomarker reflecting cellular proliferation for estimating growth fractions of various tumor types. In the present study we analyzed the features of quantitative measurements (the curve slope (λ_HU), IC, normalized iodine concentrations (NIC)) obtained from DEsCT and levels of Ki-67 protein expression. We demonstrated that the values between advanced gastric cancer (AGC) and early gastric cancer (EGC) were significantly different both in venous phase (VP) and delayed phase (DP). The values of different level of Ki-67 expression grade were significantly different both in VP and DP. The rank correlation analysis between Ki-67 grade and IC, NIC and λ_HU values showed significantly positive correlation in VP and DP. These results suggested that quantitative parameters (IC, NIC and λ_HU) in dual-energy CT imaging can be used to differentiate EGC from AGC, and have significantly positive correlation with Ki-67 antigen expression levels in gastric cancer for indicating tumor cellular proliferation.

Serum miR-126 level combined with multi- detector computed tomography in the preoperative prediction of lymph node metastasis of gastric cancer

BACKGROUND

Predicting lymph node metastasis (LNM) accurately is vital to design optimal treatment strategies preoperatively for gastric cancer (GC) patients. However, conventional tumor biomarkers and imaging techniques are not sufficient to predict LNM before surgery. miR-126 has been reported to play important roles in tumor metastasis which may represent a novel tumor biomarker.

OBJECTIVE

To assess the utility of the combination of serum miR-126 and multi-detector computed tomography (MDCT) in predicting LNM preoperatively in GC.

METHODS

Quantitative real-time polymerase chain reaction was performed to examine the serum miR-126 expression levels in 338 GC patients. MDCT was also performed. The cut-off value of preoperative serum miR-126 level for LNM was determined by receiver characteristic curve (ROC) analysis. Logistic regression analysis was used to determine independent predictors for LNM.

RESULTS

The serum miR-126 levels of GC patients with LNM were significantly lower compared with those without LNM (p< 0.05). In addition, the later the N stage was, the lower the serum miR-126 level was in GC patients (p< 0.05). With a cut-off value of 63.4, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of serum miR-126 for predicating LNM were 83.2%, 79.0%, 81.9%, 90.4% and 66.4%, respectively. The combination of serum miR-126 level and MDCT increased the accuracy of MDCT prediction for LNM from 69.2% to 86.7%. Serum miR-126 was an independent predictor for LNM.

CONCLUSIONS

These results indicate for the first time that the combination of serum miR-126 and MDCT is useful for the prediction of LNM in GC.

CT volumetry for gastric adenocarcinoma: association with lymphovascular invasion and T-stages

Purpose

To determine whether gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict presence of lymphovascular invasion and T-stages.

Results

Gross tumor volume increased with the lymphovascular invasion (r = 0.426, P < 0.0001) and T stage (r = 0.656, P < 0.0001). Univariate analysis showed gross tumor volume could predict lymphovascular invasion (P < 0.0001). Multivariate analyses indicated gross tumor volume as an independent risk factor of lymphovascular invasion (P = 0.026, odds ratio = 2.284). The Mann-Whitney U test showed gross tumor volume could distinguish T2 from T3, T1 from T2–T4a, T1–T2 from T3–T4a and T1–T3 from T4a (P = 0.000). In the development cohort, gross tumor volume could predict lymphovascular invasion (cutoff, 15.92 cm³; AUC, 0.760), and distinguish T2 from T3 (cutoff, 10.09 cm³; AUC, 0.828), T1 from T2-T4a (cutoff, 8.20 cm³; AUC, 0.860), T1-T2 from T3-T4a (cutoff, 15.88 cm³; AUC, 0.883), and T1-T3 from T4a (cutoff, 21.53 cm³; AUC, 0.834). In validation cohort, gross tumor volume could predict presence of lymphovascular invasion (AUC, 0.742), and distinguish T2 from T3 (AUC, 0.861), T1 from T2-T4a (AUC, 0.859), T1–T2 from T3–T4a (AUC, 0.875), and T1–T3 from T4a (AUC, 0.773).

Materials and Methods

360 consecutive patients with gastric adenocarcinoma were retrospectively identified. Gross tumor volume was evaluated on multidetector computed tomography images. Statistical analysis was performed to determine whether gross tumor volume could predict presence of lymphovascular invasion and T-stages. Cutoffs of gross tumor volume were first investigated in 212 patients and then validated in an independent 148 patients using area under the receiver operating characteristic curve (AUC) for predicting lymphovascular invasion and T-stages.

Conclusions

Gross tumor volume of resectable gastric adenocarcinoma at multidetector computed tomography demonstrated capability in predicting lymphovascular invasion and distinguishing T-stages.

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.

Contribution of diffusion weighted MRI to diagnosis and staging in gastric tumors and comparison with multi-detector computed tomography

Background

Diagnostic performance of Diffusion-Weighted magnetic resonance Imaging (DWI) and Multi-Detector Computed Tomography (MDCT) for TNM (Tumor, Lymph node, Metastasis) staging of gastric cancer was compared.

Patients and methods

We used axial T2-weighted images and DWI (b-0,400 and b-800 s/mm2) protocol on 51 pre-operative patients who had been diagnosed with gastric cancer. We also conducted MDCT examinations on them. We looked for a signal increase in the series of DWI images. The depth of tumor invasion in the stomach wall (tumor (T) staging), the involvement of lymph nodes (nodal (N) staging), and the presence or absence of metastases (metastatic staging) in DWI and CT images according to the TNM staging system were evaluated. In each diagnosis of the tumors, sensitivity, specificity, positive and negative accuracy rates of DWI and MDCT examinations were found through a comparison with the results of the surgical pathology, which is the gold standard method. In addition to the compatibilities of each examination with surgical pathology, kappa statistics were used.

Results

Sensitivity and specificity of DWI and MDCT in lymph node staging were as follows: N1: DWI: 75.0%, 84.6%; MDCT: 66.7%, 82%;N2: DWI: 79.3%, 77.3%; MDCT: 69.0%, 68.2%; N3: DWI: 60.0%, 97.6%; MDCT: 50.0%, 90.2%. The diagnostic tool DWI seemed more compatible with the gold standard method (surgical pathology), especially in the staging of lymph node, when compared to MDCT. On the other hand, in T staging, the results of DWI and MDCT were better than the gold standard when the T stage increased. However, DWI did not demonstrate superiority to MDCT. The sensitivity and specificity of both imaging techniques for detecting distant metastasis were 100%.

Conclusions

The diagnostic accuracy of DWI for TNM staging in gastric cancer before surgery is at a comparable level with MDCT and adding DWI to routine protocol of evaluating lymph nodes metastasis might increase diagnostic accuracy.

Decreased stage migration rate of early gastric cancer with a new reconstruction algorithm using dual-energy CT images: a preliminary study

OBJECTIVES

To evaluate the potential value of advanced monoenergetic images (AMEIs) on early gastric cancer (EGC) using dual-energy CT (DECT).

METHODS

31 EGC patients (19 men, 12 women; age range, 38-81 years; mean age, 57.19 years) were retrospectively enrolled in this study. Conventionally reconstructed polyenergetic images (PEIs) at 120 kV and virtual monoenergetic images (MEIs) and AMEIs at six different kiloelectron volt (keV) levels (from 40 to 90 keV) were evaluated from the 100 and Sn 140 kV dual energy image data, respectively. The visibility and stage migration of EGC for all three image data sets were evaluated and statistically analyzed. The objective and subjective image qualities were also evaluated.

RESULTS

AMEIs at 40 keV showed the best visibility (80.7 %) and the lowest stage migration (35.5 %) for EGC. The stage migration for AMEIs at 40 keV was significantly lower than that for PEIs (p = 0.026). AMEIs at 40 keV had statistically higher CNR in the arterial and portal phases, gastric-specific diagnostic performance and visual sharpness compared with other AMEIs, MEIs and PEIs (all p < 0.05).

CONCLUSIONS

AMEIs at 40 keV with MPR increase the CNR of EGC and thus potentially lower the stage migration of EGC.

KEY POINTS

• AMEIs benefits from the recombination of low-keV images and medium energies. • AMEIs could receive better CNR results than MEIs. • AMEIs at 40 keV potentially lower the stage migration of EGC.

Distribution patterns of metastases in recurrent laryngeal nerve lymph nodes in patients with squamous cell esophageal cancer

Esophageal cancers frequently metastasize to recurrent laryngeal nerve lymph nodes (RLNNs). Knowledge of anatomic metastatic RLNN (mRLNN) distributions is needed for lymph node dissection during esophageal cancer surgery. Among 189 patients with esophageal cancer who underwent esophagectomy between 2008 and 2010, 51 (27.0%) had mRLNN. Sixty-four mRLNNs (right, 31; left, 33) were identified via preoperative computed tomography (CT); more than 2 unilateral metastases and/or nodes with unclear boundaries were excluded. Anatomical characteristics, including vertical distance from the sternal notch level, circumferential angle to the mid-sagittal tracheal plane, and short and long axes, were measured via CT. Respective mean right and left vertical distances from the sternal notch were +2.0 ± 13.1 mm and -14.5 ± 23.8 mm (p = 0.0006). Left mRLNNs existed in vertically wider and inferior areas along recurrent laryngeal nerve, compared to right mRLNNs. The respective mean right and left circumferential angles around the trachea (from the anterior mid-sagittal plane) were 137.2 ± 11.2° and 94.3 ± 31.6° (p < 0.0001). Left mRLNNs were distributed more widely around the trachea, especially anteriorly. The short axes were larger for right mRLNNs than for left mRLNNs (8.6 mm vs. 6.8 mm, p = 0.026). Compared with the right side, left mRLNNs were smaller and had a vertically longer and circumferentially wider distribution. Careful attention should be given to the left side during curative RLNN dissection.

Clinicopathological characteristics of clinical early gastric cancer in the upper-third stomach

AIM: To elucidate the clinicopathological characteristics of clinically early gastric cancer in the upper-third stomach and to clarify treatment precautions.

METHODS: A total of 683 patients with clinical early gastric cancer were enrolled in this retrospective study, 128 of whom had gastric cancer in the upper-third stomach (U group). All patients underwent a double contrast barium examination, endoscopy, and computed tomography (CT), and were diagnosed preoperatively based on the findings obtained. The clinicopathological features of these patients were compared with those of patients with gastric cancer in the middle- and lower-third stomach (ML group). We also compared clinicopathological factors between accurate-diagnosis and under-diagnosis groups in order to identify factors affecting the accuracy of a preoperative diagnosis of tumor depth.

RESULTS: Patients in the U group were older (P = 0.029), had a higher ratio of males to females (P = 0.015), and had more histologically differentiated tumors (P = 0.007) than patients in the ML group. A clinical under-diagnosis occurred in 57 out of 683 patients (8.3%), and was more frequent in the U group than in the ML group (16.4% vs 6.3%, P < 0.0001). Therefore, the rates of lymph node metastasis and lymphatic invasion were slightly higher in the U group than in the ML group (P = 0.071 and 0.082, respectively). An under-diagnosis was more frequent in histologically undifferentiated tumors (P = 0.094) and in those larger than 4 cm (P = 0.024). The median follow-up period after surgery was 56 mo (range, 1-186 mo). Overall, survival and disease-specific survival rates were significantly lower in the U group than in the ML group (P = 0.016 and 0.020, respectively). However, limited operation-related cancer recurrence was not detected in the U group in the present study.

CONCLUSION: Clinical early gastric cancer in the upper-third stomach has distinguishable characteristics that increase the risk of a clinical under-diagnosis, especially in patients with larger or undifferentiated tumors.

Quantification of the Iodine Content of Perigastric Adipose Tissue by Dual-Energy CT: A Novel Method for Preoperative Diagnosis of T4-Stage Gastric Cancer

This study investigated the utility of quantifying iodine concentration (IC) in perigastric adipose tissue, using dual-energy computed tomography (DECT), for the detection of T4a-stage gastric cancer. Fifty-four patients with gastric cancer were enrolled at the Fourth Hospital of Hebei Medical University between January and June 2013. Patients were imaged preoperatively with conventional computed tomography (CT) scans and DECT, and the IC in perigastric fat adjacent to the tumor calculated from arterial phase (AP) and portal venous phase (PVP) images. The patients subsequently received surgical treatment (gastrectomy), and histologic analysis of resected specimens was used as a ‘gold standard’ reference for cancer staging. Receiver operating characteristic (ROC) curve analysis was employed to assess the utility of DECT for identifying T4a-stage gastric cancer, with optimal IC thresholds determined from the area under the ROC curve (AUC). Postoperative histology revealed that 32 patients had serosal invasion (group A), and 22 did not (group B). The accuracy of conventional CT for distinguishing stage T4 from non-T4 stages was 68.5% (37/54). IC was significantly higher in group A than in group B (AP: 0.60±0.34 vs. 0.09±0.19 mg/mL, p<0.001; PVP: 0.83±0.41 vs. 0.27±0.21 mg/mL, p<0.001). The sensitivity, specificity and AUC for detecting serosal invasion were 77.1%, 79.2% and 0.89 at an IC threshold of 0.25 mg/mL for AP images; and 80.0%, 79.2% and 0.90 at an IC threshold of 0.45 mg/mL for PVP images. These results indicated that Iodine quantification in perigastric fat using DECT is an accurate method for detecting serosal invasion by gastric cancer.

Three-port laparoscopic exploration is not sufficient for patients with T4 gastric cancer

Gastric cancer continues to be a leading cause of cancer death. The majority of patients with gastric adenocarcinoma in China present with advanced disease. Ruling out unresectable cancers from an unnecessary ''open'' exploration is very important. The aim of this study was to assess the value of five-port anatomical laparoscopic exploration in T4 gastric cancer in comparison with three-port laparoscopic exploration and laparotomy exploration. We conducted a retrospective study on 126 patients with T4 stage scheduled for D2 curative gastrectomy based on computed tomography (CT) staging at Department of Gastric Cancer and Soft Tissue Sarcoma, Fudan University Shanghai Cancer Center, from Apr. 2011 to Apr. 2013. Laparotomy exploration (Group I), three-port laparoscopic exploration (Group II) or five-port anatomical laparoscopic exploration (Group III) were performed prior to radical gastrectomy. Accuracy rate for feasibility of D2 curative gastrectomy in laparotomy exploration and five-port anatomical laparoscopic exploration groups was higher than that in the three-port laparoscopic exploration group. Five-port anatomical laparoscopic exploration group had the highest accuracy resection rate (Group I vs Group II vs Group III,92.6% vs78.6% vs 97.7%; p<0.05) and shorter length of hospitalization (Group I vs Group II vs Group III, 9.58±4.17 vs 6.13±2.85 vs 5.00±1.81; p<0.001). Three-port laparoscopic exploration has low accuracy rate for assessing feasibility of D2 curative gastrectomy and five-port anatomical laparoscopic exploration should be performed on patients with T4 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).

[Synopsis on clinical practice guideline of gastric cancer in Korea: an evidence-based approach]

Although, gastric cancer is quite common in Korea, the treatment outcome is relatively favorable compared to that of Western countries. However, there is no Korean multidisciplinary guideline for gastric cancer and thus, a guideline adequate for domestic circumstances is required. Experts from related societies developed 22 recommendation statements for the diagnosis (n=9) and treatment (n=13) based on relevant key questions. Evidence levels based on systematic review of literatures were classified as five levels from A to E, and recommendation grades were classified as either strong or weak. The topics of this guideline cover diagnostic modalities (endoscopy, endoscopic ultrasound, radiologic diagnosis), treatment modalities (surgery, therapeutic endoscopy, chemotherapy, radiotherapy) and pathologic evaluation. External review of the guideline was conducted at the finalization phase.

Accuracy of multidetector-row CT in diagnosing lymph node metastasis in patients with gastric cancer

OBJECTIVES

The purpose of this study was to determine the optimal cut-off value of lymph node size for diagnosing metastasis in gastric cancer with multidetector-row computed tomography (MDCT) after categorizing perigastric lymph nodes into three regions.

METHODS

The study included 90 gastric cancer patients who underwent gastrectomy. The long-axis diameter (LAD) and short-axis diameter (SAD) of all visualized lymph nodes were measured with transverse MDCT images. The locations of lymph nodes were categorized into three regions: lesser curvature, greater curvature, and suprapancreatic. The diagnostic value of lymph node metastasis was assessed with receiver operating characteristic (ROC) analysis.

RESULTS

The area under the curve was larger for SAD than LAD in all groups. The optimal cut-off values of SAD were determined as follows: overall, 9 mm; differentiated type, 9 mm; undifferentiated type, 8 mm; lesser curvature region, 7 mm; greater curvature region, 6 mm; and suprapancreatic region, 9 mm. The diagnostic accuracies for lymph node metastasis using individual cut-off values were 71.1% based on histological type and 76.6% based on region of lymph node location.

CONCLUSIONS

The diagnostic accuracy of lymph node metastasis in gastric cancer was improved by using individual cut-off values for each lymph node region.

KEY POINTS

• Multidetector-row computed tomography is widely used to predict pathological nodal status. • An optimal cut-off value of lymph node size has not been determined. • Cut-off values were assessed according to histology and nodal location. • The optimal cut-off values differed based on histology and nodal location. • Diagnostic accuracy was improved by using individual cut-off values for each region.

Clinical practice guidelines for gastric cancer in Korea: an evidence-based approach

Although gastric cancer is quite common in Korea, the treatment outcome is relatively favorable compared to those in western countries. However, there are currently no Korean multidisciplinary guidelines for gastric cancer. Experts from related societies developed guidelines de novo to meet Korean circumstances and requirements, including 23 recommendation statements for diagnosis (n=9) and treatment (n=14) based on relevant key questions. The quality of the evidence was rated according to the GRADE evidence evaluation framework: the evidence levels were based on a systematic review of the literature, and the recommendation grades were classified as either strong or weak. The applicability of the guidelines was considered to meet patients' view and preferences in the context of Korea. The topics of the guidelines cover diagnostic modalities (endoscopy, endoscopic ultrasound, and radiologic diagnosis), treatment modalities (surgery, therapeutic endoscopy, chemotherapy, and radiotherapy), and pathologic evaluation. An external review of the guidelines was conducted during the finalization phase.

Progress in diagnosis and treatment of precancerous lesions and early gastric cancer

Gastric cancer is the fourth most prevalent cancer worldwide and the second cause of cancer-related death. The 5-year survival rate for early gastric cancer after treatment is 84%-99%. Early detection and treatment of precancerous lesions are pivotal to improved patient survival. The development of various endoscopic (e.g., endoscopic ultrasound, narrowband imaging, magnifying endoscopy and chromoendoscopy), imaging and laboratory technologies has significantly improved the rate of diagnosis of early cancer and precancerous lesions. In addition, endoscopic techniques (e.g., endoscopic submucosal dissection) and minimally invasive surgery (e.g., laparoscopy) make the therapy of early cancer and precancerous lesions better and less invasive, reduce the incidence of postoperative complications, and improve the quality of life of patients after surgery.

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.

Feasibility of laparoscopy-assisted total gastrectomy in patients with clinical stage I gastric cancer

BACKGROUND

Laparoscopy-assisted total gastrectomy (LATG) for gastric cancer is not yet widespread because of the technical difficulty of reconstruction. We have performed LATG on 100 patients with clinical stage I gastric cancer. This study investigated the short-term outcomes of LATG.

METHODS

Between September 2001 and September 2012, 100 patients with clinical stage I gastric cancer underwent LATG with D1 plus beta or D2 lymphadenectomy. Roux-en-Y esophagojejunostomy was performed intracorporeally using end-to-side anastomosis with a circular stapler (the purse-string suture method). The primary endpoint was the proportion of postoperative complications during hospitalization.

RESULTS

Mean operation time was 249 min; mean blood loss was 182 ml. There were no conversions to open surgery. According to the Clavien-Dindo classification, there were 8 grade II (8 %) and 10 grade IIIa/b (10 %) complications. There were no treatment-related deaths or grade IV complications. The most frequent complication was anastomotic or stump leakage (6 %), followed by pancreatic fistula (5 %). Reoperations were required in two patients with leakage.

CONCLUSIONS

The short-term outcomes of LATG in our study involving 100 patients were outlined. LATG for gastric cancer patients should be attempted preferably in a clinical trial setting by surgeons with sufficient experience in laparoscopic gastrectomy.

Added value of diffusion-weighted MR imaging to T2-weighted and dynamic contrast-enhanced MR imaging in T staging of gastric cancer

OBJECTIVE

To assess the utilization of diffusion-weighted (DW) magnetic resonance (MR) imaging in T staging of gastric cancer prospectively.

METHODS

Fifty-one patients underwent T2-weighted (T2W), contrast-enhanced (CE) and DW MR imaging. Two radiologists independently interpreted the images for T staging of the tumors.

RESULTS

The overall accuracy of T staging in pT1-4 gastric cancers by T2W+CE+DW (88.2%) was significantly higher than that by T2W+CE and T2W+DW (both 76.5%, P=.031).

CONCLUSION

DW adds useful information to T2W and CE MR imaging in T staging of gastric cancer.

Gastric cancer staging with dual energy spectral CT imaging

Purpose

To evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers.

Materials and Methods

96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings.

Results

The overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP.

Conclusion

The monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes.

The role of CT and staging laparoscopy in the staging of gastric cancer

AIM

To assess the relative roles of computed tomography (CT) and diagnostic laparoscopy in the staging process of patients with potentially curable gastric cancer.

MATERIALS AND METHODS

Fifty-two patients underwent laparoscopy and CT as part of staging; 36 patients underwent surgery without laparoscopy. Pathological findings at laparoscopy or surgery were compared with initial CT reports, and analysis of the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was performed.

RESULTS

Of the patients who underwent laparoscopy and CT, six were staged as positive for peritoneal disease (PD), of which five (83%) were positive for PD at laparoscopy. Forty-six patients were reported at CT as negative for PD, of which 40 (87%) were negative at laparoscopy. Of 36 patients with no advanced disease at CT, who had surgery without diagnostic laparoscopy, nine (25%) were positive at surgery for PD. The overall sensitivity of CT for PD was therefore 25%, the specificity was 99%, the PPV was 86%, and the NPV was 83%.

CONCLUSION

CT is not sufficiently sensitive to detect or exclude PD in patients with gastric cancer, although is highly specific. Staging laparoscopy is an essential adjunct to imaging in all patients being considered for curative surgery for gastric cancer.