A prospective validation study to diagnose serosal invasion and nodal metastases of gastric cancer by multidetector-row CT

A Clinical-Radiomic Combined Model based on Dual-Layer Spectral CT for Predicting Pathological T4 in Gastric Cancer

RATIONALE AND OBJECTIVES

This study aimed to develop and validate a dual-layer spectral CT based clinical-radiomic model for pre-treatment prediction of pathological T4 (pT4) in gastric cancer (GC) patients.

MATERIALS AND METHODS

This retrospective study included 148 surgically confirmed GC patients who underwent dual-layer spectral CT scanning before surgery and were divided into a training (n=104) and test (n=44) cohorts. Subjective assessments were performed based on conventional 120-kV CT images by two readers. Clinical models were developed using patient demographics, serum tumor markers, and image features from CT scans. Radiomics model included features extracted from conventional 120-kV CT and dual-layer CT-derived spectral base image (SBI), such as virtual monoenergetic images (40 keV, 70 keV, 100 keV), iodine density (ID), effective atomic number (Zeff), and electron density (ED) images for both the arterial phase (AP) and portal venous phase (PVP). A clinical-radiomic combined model was developed and visualized using a nomogram.

RESULTS

Tumor thickness on CT and serum level of CA19-9 levels were identified as independent predictors. The clinical-radiomic combined model demonstrated superior performance compared to subjective image interpretation and other models, with an AUC of 0.906 (95% CI, 0.848-0.963) in the training cohort and 0.873 in the test cohort. The nomogram was significantly associated with pT4 status, supporting its potential utility in clinical prediction.

CONCLUSION

The integration of clinical characteristics with radiomic features from conventional CT and dual-layer CT-derived SBI achieved a high diagnostic accuracy for predicting pT4 in GC patients. This combined approach could assist in treatment planning and patient management in GC.

Oncological risk of proximal gastrectomy for proximal advanced gastric cancer after neoadjuvant chemotherapy

PURPOSE

This study assesses the metastasis rate of the key distal lymph nodes (KDLN) that are not routinely dissected in proximal gastrectomy, aiming to explore the oncological safety of proximal gastrectomy for upper gastric cancer who underwent neoadjuvant chemotherapy.

METHODS

We analyzed a cohort of 150 patients with proximal locally advanced gastric cancer (cT3/4 before chemotherapy) from two high-volume cancer centers in China who received preoperative neoadjuvant chemotherapy (NAC) and total gastrectomy with lymph node dissection. Metastasis rate of the KDLN (No.5/6/12a) and the risk factors were analyzed.

RESULTS

Key distal lymph node metastasis was detected in 10% (15/150) of patients, with a metastasis rate of 6% (9/150) in No. 5 lymph nodes, 6.7% (10/150) in No. 6 lymph nodes, and 2.7% (2/75) in No. 12a lymph nodes. The therapeutic value index of KDLN as one entity is 5.8. Tumor length showed no correlation with KDLN metastasis, while tumor regression grade (TRG) emerged as an independent risk factor (OR: 1.47; p-value: 0.04). Of those with TRG3 (no response to NAC), 80% (12/15) was found with KDLN metastasis.

CONCLUSION

For cT3/4 proximal locally advanced gastric cancer patients, the risk of KDLN metastasis remains notably high even after NAC. Therefore, proximal gastrectomy is not recommended; instead, total gastrectomy with thorough distal lymphadenectomy is the preferred surgical approach.

Serum Interleukin 6 Level is Associated With Overall Survival and Treatment Response in Gastric and Gastroesophageal Junction Cancer

OBJECTIVE

To identify novel prognostic and predictive biomarkers for gastric and gastroesophageal junction (G+GEJ) adenocarcinoma.

BACKGROUND

There are few biomarkers to guide treatment for G+GEJ. The systemic inflammatory response of G+GEJ patients is associated with survival. In this study, we evaluated the relationship of circulating serum cytokine levels with overall survival (OS) and pathologic tumor regression grade (TRG) in G+GEJ patients.

PATIENTS AND METHODS

We queried the UT Southwestern gastric cancer biobank to identify consecutive patients diagnosed with G+GEJ from 2016 to 2022; these patients had pretreatment serum collected at diagnosis. For patients who received neoadjuvant therapy, an additional serum sample was collected immediately before surgical resection. An unbiased screen of 17 cytokines was measured in a discovery cohort. A multivariable Cox proportional hazards model was used to assess the association of cytokine concentration with OS. Findings were validated in additional patients. In patients who received neoadjuvant therapy, we assessed whether the change in interleukin 6 (IL-6) after therapy was associated with TRG.

RESULTS

Sixty-seven patients were included in the discovery cohort, and IL-6 was the only pretreatment cytokine associated with OS; this was validated in 134 other patients (hazard ratio: 1.012 per 1 pg/mL increase, 95% CI: 1.006-1.019, P = 0.0002). Patients in the top tercile of IL-6 level had worse median OS (10.6 months) compared with patients in the intermediate (17.4 months) and bottom tercile (35.8 months, P < 0.0001). Among patients who underwent neoadjuvant therapy (n = 50), an unchanged or decrease in IL-6 level from pretreatment to posttreatment, had a sensitivity and specificity of 80% for predicting complete or near-complete pathologic tumor regression (TRG 0-1).

CONCLUSIONS

Pretreatment serum level of IL-6 is a promising prognostic biomarker for G+GEJ patients. Comparing pre and post-neoadjuvant IL-6 levels may predict pathologic response to neoadjuvant therapy.

A radio-pathologic integrated model for prediction of lymph node metastasis stage in patients with gastric cancer

BACKGROUND

Accurate prediction of lymph node metastasis stage (LNMs) facilitates precision therapy for gastric cancer. We aimed to develop and validate a deep learning-based radio-pathologic model to predict the LNM stage in patients with gastric cancer by integrating CT images and histopathological whole-slide images (WSIs).

METHODS

A total of 252 patients were enrolled and randomly divided into a training set (n = 202) and a testing set (n = 50). Both pretreatment contrast-enhanced abdominal CT and WSI of biopsy specimens were collected for each patient. The deep radiologic and pathologic features were extracted from CT and WSI using ResNet-50 and Vision Transformer (ViT) network, respectively. By fusing both radiologic and pathologic features, a radio-pathologic integrated model was constructed to predict the five LNM stages. For comparison, four single-modality models using CT images or WSIs were also constructed, respectively. All models were trained on the training set and validated on the testing set.

RESULTS

The radio-pathologic integrated mode achieved an overall accuracy of 84.0% and a kappa coefficient of 0.795 on the testing set. The areas under the curves (AUCs) of the integrated model in predicting the five LNM stages were 0.978 (95% Confidence Interval (CI 0.917-1.000), 0.946 (95% CI 0.867-1.000), 0.890 (95% CI 0.718-1.000), 0.971 (95% CI 0.920-1.000), and 0.982 (95% CI 0.911-1.000), respectively. Moreover, the integrated model achieved an AUC of 0.978 (95% CI 0.912-1.000) in predicting the binary status of nodal metastasis.

CONCLUSION

Our study suggests that radio-pathologic integrated model that combined both macroscale radiologic image and microscale pathologic image can better predict lymph node metastasis stage in patients with gastric cancer.

Intraoperative Diagnosis of Serosal Invasion in Gastric Cancer by Magnifying Endoscopy with Narrow-Band Imaging for Intraoperative Measurement Decision

Purpose: To establish a precise diagnostic method for serosal invasion in gastric cancer (GC) during surgery using therapeutic measures, and facilitate quick decision-making. Methods: A total of 19 GC patients treated in the department of gastrointestinal surgery of Fujian Provincial Hospital between April 2019 and December 2020 were enrolled. An electronic gastroscopy with a magnifying endoscope with narrow-band imaging was used to photograph the serosal surface of the GC lesion site and the normal gastric wall around the lesion during surgery. The endoscopic diagnosis was confirmed on the basis of the microvascular phenotype of the serosal surface and validated by comparison with the pathological diagnosis. Results: Under the specific endoscopy, serosal invasion, including subserosal tissue invasion and serosal layer invasion, was diagnosed by observing the capillary morphology change, and capillary diameter and density increase. According to the pathological diagnosis, the accuracy of serosal invasion diagnosis was 94.7%, the sensitivity was 100%, the specificity was 75%, the positive predictive value was 93.8%, and the negative predictive value was 100%. To further distinguish the subserosal tissue invasion and serosal layer invasion, the magnifying endoscope with narrow-band imaging possessed a 78.9% accuracy by distinguishing irregular changes in microvessels. Conclusions: Magnifying endoscope with narrow-band imaging is less time-consuming than pathological diagnosis. Intraoperative diagnosis using microvascular observation can accurately detect serosal invasion. It is of value for the intraoperative diagnosis in GC patients.

Linear EUS Accuracy in Preoperative Staging of Gastric Cancer: A Retrospective Multicenter Study

INTRODUCTION

Preoperative gastric cancer (GC) staging is the most reliable prognostic factor that affects therapeutic strategies. Contrast-enhanced computed tomography (CECT) and radial endoscopic ultrasound (R-EUS) scans are the most commonly used staging tools for GC. The accuracy of linear EUS (L-EUS) in this setting is still controversial. The aim of this retrospective multicenter study was to evaluate the accuracy of L-EUS and CECT in preoperative GC staging, with regards to depth of tumor invasion (T staging) and nodal involvement (N staging).

MATERIALS AND METHODS

191 consecutive patients who underwent surgical resection for GC were retrospectively enrolled. Preoperative staging had been performed using both L-EUS and CECT, and the results were compared to postoperative staging by histopathologic analysis of surgical specimens.

RESULTS

L-EUS diagnostic accuracy for depth of invasion of the GC was 100%, 60%, 74%, and 80% for T1, T2, T3, and T4, respectively. CECT accuracy for T staging was 78%, 55%, 45%, and 10% for T1, T2, T3, and T4, respectively. L-EUS diagnostic accuracy for N staging of GC was 85%, significantly higher than CECT accuracy (61%).

CONCLUSIONS

Our data suggest that L-EUS has a higher accuracy than CECT in preoperative T and N staging of GC.

Preoperative diagnosis of tumor depth in gastric cancer using transabdominal ultrasonography compared to using endoscopy and computed tomography

BACKGROUND

An accurate evaluation method for preoperative diagnosis has not yet been established in patients with gastric cancer (GC), though it is essential for optimal treatment. Current standard modalities are endoscopy and contrast computed tomography (CT). In this study, we investigated the efficacy and limitations of transabdominal ultrasonography (TUS) for the assessment of tumor invasion.

METHODS

We enrolled 178 consecutive patients with GC evaluated by TUS, endoscopy, and contrast CT before gastrectomy. For the TUS examination, patients ingested water to fill their stomachs. The clinical staging determined using these modalities was compared to the pathological staging.

RESULTS

The overall accuracy of clinical T staging using TUS was 47.8% (pT1a: 5.8% (2/35); pT1b: 58.8% (20/35); pT2: 69.6% (16/23); pT3: 66.7% (22/33); pT4a: 46% (23/50); pT4b: 100% (2/2)). Using endoscopy, contrast CT, and TUS, the overall accuracy was 60.7%. The accuracy of TUS was associated with the tumor region (U region: 50% (14/28); M: 31.8% (14/44); L: 53.7% (57/106); P = 0.048), but not with the cross-sectional parts (P = 0.49). Multivariate analysis identified inaccurate TUS as independently correlating with tumor region (M vs. U/L, odds ratio (OR) = 3.11, 95% confidence interval (CI) 1.41-6.87; P = 0.005) and pT (pT1 vs. pT2-4, OR = 3.00, 95%CI 1.31-6.87; P = 0.009).

CONCLUSIONS

The present study demonstrated the importance of TUS in evaluating GC. Thus, TUS may be useful for clinical T staging in certain circumstances, leading to treatment optimization.

Clinicopathological characteristics and treatment outcome of resectable gastric cancer patients with small para-aortic lymph node

Background

Resectable gastric cancer (GC) patients with small para-aortic lymph node (smaller than 10mm in diameter, sPAN) were seldom reported, and existing guidelines did not provide definite treatment recommendation for them.

Methods

A total of 667 consecutive resectable GC patients were enrolled. 98 patients were in the sPAN group, and 569 patients without enlarged para-aortic lymph node were in the nPAN group. Standard D2 lymphadenectomy was performed. Neoadjuvant and adjuvant chemotherapy were administrated according to the cTNM and pTNM stage, respectively. Clinicopathological features and prognosis were compared between these two groups.

Results

The median size of sPAN was 6 (range, 2-9) mm and the distribution was prevalent in No. 16b1. cN stage (p=0.001) was significantly related to the presence of sPAN. sPAN was both independent risk factor for OS (p=0.031) and RFS (p=0.046) of all patients. The prognosis of patients with sPAN was significantly worse than that of patients with nPAN (OS: p=0.008; RFS: p=0.007). Preoperative CEA and CA19-9 were independent risk factors for prognosis of patients with sPAN. Furthermore, patients in the sPAN group with normal CEA and CA19-9 exhibited acceptable prognosis (5-year OS: 67%; RFS: 64%), while those with elevated CEA or CA19-9 suffered significantly poorer prognosis (5-year OS: 17%; RFS: 17%) than patients in the nPAN group (5-year OS: 64%; RFS 62%) (both p < 0.05).

Conclusions

Standard D2 lymphadenectomy should be considered a valid approach for GC patients with sPAN associate to normal preoperative CEA and CA19-9 levels. Patients with sPAN associated to elevated CEA or CA19-9 levels could benefit from a multimodal approach: neoadjuvant chemotherapy; radical surgery with D2 plus lymph nodal dissection extended to No. 16 station.

Model based on preoperative clinical characteristics to predict lymph node metastasis in patients with gastric cancer

Background

The risk factors of lymph node metastasis (LNM) in gastric cancer (GC) remain controversial. We aimed to identify risk factors of LNM in GC and construct a predictive model.

Methods

A total of 1,337 resectable GC patients who underwent radical D2 lymphadenectomy at the first affiliated Hospital of Anhui Medical University from January 2011 to January 2014 were retrospectively analyzed and randomly divided into training and validation cohorts (n = 1,003 and n = 334, respectively) in a 3:1 ratio. Collecting indicators include age, gender, body mass index (BMI), tumor location, pathology, histological grade, tumor size, preoperative neutrophils to lymphocytes ratio (NLR), platelets to lymphocytes ratio (PLR), fibrinogen to albumin ratio (FAR), carcinoembryonic antigen (CEA), cancer antigen19-9 (CA19-9) and lymph nodes status. Significant risk factors were identified through univariate and multivariate logistic regression analysis, which were then included and presented as a nomogram. The performance of the model was assessed with receiver operating characteristic curves (ROC curves), calibration plots, and Decision curve analysis (DCA), and the risk groups were divided into low-and high-risk groups according to the cutoff value which was determined by the ROC curve.

Results

BMI, histological grade, tumor size, CEA, and CA19-9 were enrolled in the model as independent risk factors of LNM. The model showed good resolution, with a C-index of 0.716 and 0.727 in the training and validation cohort, respectively, and good calibration. The cutoff value for predicted probability is 0.594, the proportion of patients with LNM in the high-risk group was significantly higher than that in the low-risk group. Decision curve analysis also indicated that the model had a good positive net gain.

Conclusions

The nomogram-based prediction model developed in this study is stable with good resolution, reliability, and net gain. It can be used by clinicians to assess preoperative lymph node metastasis and risk stratification to develop individualized treatment plans.

Gastric hydrodistension CT versus CT without gastric distension in preoperative TN staging of gastric carcinoma: analysis of single-center cancer registry

Accurate staging of gastric cancer is essential for the selection and optimization of therapy. Hydrodistension of the stomach is recommended to improve the accuracy of preoperative staging with contrast-enhanced multidetector computed tomography (MDCT). This study compares the performance of contrast-enhanced gastric water distension versus a nondistension MDCT protocol for T and N staging and serosal invasion in comparison to surgical histopathology. After propensity score matching, 86 patients in each group were included for analysis. The overall accuracy of distension versus nondistension group in T staging was 45% (95% CI 35-56) and 55% (95% CI 44-65), respectively (p = 0.29). There was no difference in the sensitivity and specificity in individual T staging and assessment of serosal invasion (all p > 0.41). Individual stage concordance with pathology was not significantly different (all p > 0.41). The overall accuracy of N staging was the same for distension and nondistension groups (51% [95% CI 40-62]). The majority of N0 staging (78-81%) were correctly staged, whereas N3 staging cases (63-68%) were predominantly understaged. In summary, there was no significant difference in the diagnostic performance of individual TN staging and assessment of serosal invasion using MDCT with or without gastric water distension.

Impact of tumor-related factors and inter-institutional heterogeneity on preoperative T staging for gastric cancer

Background: To improve the diagnostic accuracy of preoperative T staging in gastric cancer, the authors evaluated tumor-related factors that might affect the diagnosis. Materials & methods: The authors analyzed the data of cT2-4b gastric cancer patients enrolled in the prospective, multicenter JCOG1302A study. They used contrast-enhanced computed tomography to analyze the association between tumor-related factors and the diagnostic accuracy of T3-4b staging for gastric cancer. Results: Among 876 cT3-4b tumors, the diagnostic accuracy was relatively low in the lower third of the stomach compared with those in the upper or middle. A multivariable analysis revealed that accuracy was higher in the lesser curvature or entire circumference region than in other areas (p < 0.001), in macroscopic types 3/5 than in types 0/1/2 (p = 0.003) and in the undifferentiated histological type than in the differentiated type (p = 0.011). Conclusion: The authors found tumor-related factors affecting preoperative T staging by enhanced computed tomography.

Predictors of Metastatic Lymph Nodes at Preoperative Staging CT in Gastric Adenocarcinoma

Background. The aim of this study was to identify the most accurate computed-tomography (CT) dimensional criteria of loco-regional lymph nodes (LNs) for detecting nodal metastases in gastric cancer (GC) patients. Methods. Staging CTs of surgically resected GC were jointly reviewed by two radiologists, considering only loco-regional LNs with a long axis (LA) ≥ 5 mm. For each nodal group, the short axis (SA), volume and SA/LA ratio of the largest LN, the sum of the SAs of all LNs, and the mean of the SA/LA ratios were plotted in ROC curves, taking the presence/absence of metastases at histopathology for reference. On a per-patient basis, the sums of the SAs of all LNs, and the sums of the SAs, volumes, and SA/LA ratios of the largest LNs in all nodal groups were also plotted, taking the presence/absence of metastatic LNs in each patient for reference. Results. Four hundred and forty-three nodal groups were harvested during surgery from 107 patients with GC, and 173 (39.1%) were metastatic at histopathology. By nodal group, the sum of the SAs showed the best Area Under the Curve (AUC), with a sensitivity/specificity of 62.4/72.6% using Youden’s index with a >8 mm cutoff. In the per-patient analysis, the sum of the SAs of all LNs in the loco-regional nodal groups showed the best AUC with a sensitivity/specificity of 65.6%/83.7%, using Youden’s index with a >39 mm cutoff. Conclusion. In patients with GC, the sum of the SAs of all the LNs at staging CT is the best predictor among dimensional LNs criteria of both metastatic invasion of the nodal group and the presence of metastatic LNs.

Diagnosis of Serosal Invasion in Gastric Adenocarcinoma by Dual-Energy CT Radiomics: Focusing on Localized Gastric Wall and Peritumoral Radiomics Features

Objectives

To build a radiomics model and combined model based on dual-energy CT (DECT) for diagnosing serosal invasion in gastric adenocarcinoma.

Materials and methods

231 gastric adenocarcinoma patients were enrolled and randomly divided into a training (n = 132), testing (n = 58), and independent validation (n = 41) cohort. Radiomics features were extracted from the rectangular ROI of the 120-kV equivalent mixed images and iodine map (IM) images in the venous phase of DECT, which was manually delineated perpendicularly to the gastric wall in the deepest location of tumor infiltration, including the peritumoral adipose tissue within 5 mm outside the serosa. The random forest algorithm was used for radiomics model construction. Traditional features were collected by two radiologists. Univariate and multivariate logistic regression was used to construct the clinical model and combined model. The diagnostic efficacy of the models was evaluated using ROC curve analysis and compared using the Delong's test. The calibration curves were used to evaluate the calibration performance of the combined model.

Results

Both the radiomics model and combined model showed high efficacy in diagnosing serosal invasion in the training, testing and independent validation cohort, with AUC of 0.90, 0.90, and 0.85 for radiomics model; 0.93, 0.93, and 0.89 for combined model. The combined model outperformed the clinical model (AUC: 0.76, 0.76 and 0.81).

Conclusion

The radiomics model and combined model constructed based on tumoral and peritumoral radiomics features derived from DECT showed high diagnostic efficacy for serosal invasion in gastric adenocarcinoma.

Advanced gastric cancer: CT radiomics prediction and early detection of downstaging with neoadjuvant chemotherapy

OBJECTIVES

To develop and evaluate machine learning models using baseline and restaging computed tomography (CT) for predicting and early detecting pathological downstaging (pDS) with neoadjuvant chemotherapy in advanced gastric cancer (AGC).

METHODS

We collected 292 AGC patients who received neoadjuvant chemotherapy. They were classified into (a) primary cohort (206 patients with 3-4 cycles chemotherapy) for model development and internal validation, (b) testing cohort I (46 patients with 3-4 cycles chemotherapy) for evaluating models' predictive ability before and after the complete course, and (c) testing cohort II (n = 40) for model evaluation on its performance at early treatment. We extracted 1,231 radiomics features from venous phase CT at baseline and restaging. We selected radiomics models based on 28 cross-combination models and measured the areas under the curve (AUC). Our prediction radiomics (PR) model is designed to predict pDS outcomes using baseline CT. Detection radiomics (DR) model is applied to restaging CT for early pDS detection.

RESULTS

PR model achieved promising outcomes in two testing cohorts (AUC 0.750, p = .009 and AUC 0.889, p = .000). DR model also showed a good predictive ability (AUC 0.922, p = .000 and AUC 0.850, p = .000), outperforming the commonly used RECIST method (NRI 39.5% and NRI 35.4%). Furthermore, the improved DR model with averaging outcome scores of PR and DR models showed boosted results in two testing cohorts (AUC 0.961, p = .000 and AUC 0.921, p = .000).

CONCLUSIONS

CT-based radiomics models perform well on prediction and early detection tasks of pDS and can potentially assist surgical decision-making in AGC patients.

KEY POINTS

• Baseline contrast-enhanced computed tomography (CECT)-based radiomics features were predictive of pathological downstaging, allowing accurate identification of non-responders before therapy. • Restaging CECT-based radiomics features were predictive to achieve pDS after and even at an early stage of neoadjuvant chemotherapy. • Combination of baseline and restaging CECT-based radiomics features was promising for early detection and preoperative evaluation of pathological downstaging of AGC.

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.

Establishment of the Radiologic Tumor Invasion Index Based on Radiomics Splenic Features and Clinical Factors to Predict Serous Invasion of Gastric Cancer

Background

Currently, there are shortcomings in diagnosing gastric cancer with or without serous invasion, making it difficult for patients to receive appropriate treatment. Therefore, we aimed to develop a radiomic nomogram for preoperative identification of serosal invasion.

Methods

We selected 315 patients with gastric cancer, confirmed by pathology, and randomly divided them into two groups: the training group (189 patients) and the verification group (126 patients). We obtained patient splenic imaging data for the training group. A p-value of <0.05 was considered significant for features that were selected for lasso regression. Eight features were chosen to construct a serous invasion prediction model. Patients were divided into high- and low-risk groups according to the radiologic tumor invasion risk score. Subsequently, univariate and multivariate regression analyses were performed with other invasion-related factors to establish a visual combined prediction model.

Results

The diagnostic accuracy of the radiologic tumor invasion score was consistent in the training and verification groups (p<0.001 and p=0.009, respectively). Univariate and multivariate analyses of invasion risk factors revealed that the radiologic tumor invasion index (p=0.002), preoperative hemoglobin <100 (p=0.042), and the platelet and lymphocyte ratio <92.8 (p=0.031) were independent risk factors for serosal invasion in the training cohort. The prediction model based on the three indexes accurately predicted the serosal invasion risk with an area under the curve of 0.884 in the training cohort and 0.837 in the testing cohort.

Conclusions

Radiological tumor invasion index based on splenic imaging combined with other factors accurately predicts serosal invasion of gastric cancer, increases diagnostic precision for the most effective treatment, and is time-efficient.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2021

There exist differences in the epidemiological characteristics, clinicopathological features, tumor biological characteristics, treatment patterns, and drug selections between gastric cancer patients from the Eastern and Western countries. The Chinese Society of Clinical Oncology (CSCO) has organized a panel of senior experts specializing in all sub-specialties of gastric cancer to compile a clinical guideline for the diagnosis and treatment of gastric cancer since 2016 and renews it annually. Taking into account regional differences, giving full consideration to the accessibility of diagnosis and treatment resources, these experts have conducted expert consensus judgment on relevant evidence and made various grades of recommendations for the clinical diagnosis and treatment of gastric cancer to reflect the value of cancer treatment and meeting health economic indexes in China. The 2021 CSCO Clinical Practice Guidelines for Gastric Cancer covers the diagnosis, treatment, follow-up, and screening of gastric cancer. Based on the 2020 version of the CSCO Chinese Gastric Cancer guidelines, this updated guideline integrates the results of major clinical studies from China and overseas for the past year, focused on the inclusion of research data from the Chinese population for more personalized and clinically relevant recommendations. For the comprehensive treatment of non-metastatic gastric cancer, attentions were paid to neoadjuvant treatment. The value of perioperative chemotherapy is gradually becoming clearer and its recommendation level has been updated. For the comprehensive treatment of metastatic gastric cancer, recommendations for immunotherapy were included, and immune checkpoint inhibitors from third-line to the first-line of treatment for different patient groups with detailed notes are provided.

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.

Potential Value of Radiomics in the Identification of Stage T3 and T4a Esophagogastric Junction Adenocarcinoma Based on Contrast-Enhanced CT Images

Purpose

This study was designed to evaluate the predictive performance of contrast-enhanced CT-based radiomic features for the personalized, differential diagnosis of esophagogastric junction (EGJ) adenocarcinoma at stages T3 and T4a.

Methods

Two hundred patients with T3 (n = 44) and T4a (n = 156) EGJ adenocarcinoma lesions were enrolled in this study. Traditional computed tomography (CT) features were obtained from contrast-enhanced CT images, and the traditional model was constructed using a multivariate logistic regression analysis. A radiomic model was established based on radiomic features from venous CT images, and the radiomic score (Radscore) of each patient was calculated. A combined nomogram diagnostic model was constructed based on Radscores and traditional features. The diagnostic performances of these three models (traditional model, radiomic model, and nomogram) were assessed with receiver operating characteristics curves. Sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and areas under the curve (AUC) of models were calculated, and the performances of the models were evaluated and compared. Finally, the clinical effectiveness of the three models was evaluated by conducting a decision curve analysis (DCA).

Results

An eleven-feature combined radiomic signature and two traditional CT features were constructed as the radiomic and traditional feature models, respectively. The Radscore was significantly different between patients with stage T3 and T4a EGJ adenocarcinoma. The combined nomogram performed the best and has potential clinical usefulness.

Conclusions

The developed combined nomogram might be useful in differentiating T3 and T4a stages of EGJ adenocarcinoma and may facilitate the decision-making process for the treatment of T3 and T4a EGJ adenocarcinoma.

Accuracy of 18F-FDG PET/CT and CECT for primary staging and diagnosis of recurrent gastric cancer: A meta-analysis

Contrast-enhanced computed tomography (CECT) is commonly used for staging and diagnosing recurrent gastric cancer. Recently, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT gained popularity as a diagnostic tool owing to advantages including dual functional and anatomical imaging, which may facilitate early diagnosis. The diagnostic performance of 18F-FDG PET/CT and CECT has been assessed in several studies but with variable results. Therefore, the present meta-analysis aimed to evaluate the accuracy of 18F-FDG PET/CT and CECT for primary TNM staging and the diagnosis of recurrent gastric cancers. A systematic search of the PubMed Central, Medline, Scopus, Cochrane and Embase databases from inception until January 2020 was performed. The Quality Assessment of Diagnostic Accuracy Study-2 tool was used to determine the quality of the selected studies. Pooled estimates of sensitivity and specificity were calculated. A total of 58 studies comprising 9,997 patients were included. Most studies had a low risk of bias. The sensitivity and specificity for nodal staging of gastric cancer were 49% (95% CI, 37-61%) and 92% (95% CI, 86-96%) for 18F-FDG PET/CT, respectively, and 67% (95% CI, 57-76%) and 86% (95% CI, 81-89%) for CECT, respectively. For metastasis staging, the sensitivity and specificity were 56% (95% CI, 40-71%) and 97% (95% CI, 87-99%) for 18F-FDG PET/CT, respectively, and 59% (95% CI, 41-75%) and 96% (95% CI, 83-99%) for CECT, respectively. For diagnosing cancer recurrence, the pooled sensitivity and specificity were 81% (95% CI, 72-88%) and 83% (95% CI, 74-89%) for 18F-FDG PET/CT, respectively, and 59% (95% CI, 41-75%) and 96% (95% CI, 83-99%) for CECT, respectively. Both 18F-FDG PET/CT and CECT were deemed highly useful for diagnosing recurrent gastric cancer due to their high sensitivities and specificities. However, these techniques cannot be used to exclude or confirm the presence of lymph node metastases or recurrent gastric cancer tumors, but can be used for the confirmation of distal metastasis.

The Performance of a Dual-Energy CT Derived Radiomics Model in Differentiating Serosal Invasion for Advanced Gastric Cancer Patients After Neoadjuvant Chemotherapy: Iodine Map Combined With 120-kV Equivalent Mixed Images

Objectives

The aim was to determine whether the dual-energy CT radiomics model derived from an iodine map (IM) has incremental diagnostic value for the model based on 120-kV equivalent mixed images (120 kVp) in preoperative restaging of serosal invasion with locally advanced gastric cancer (LAGC) after neoadjuvant chemotherapy (NAC).

Methods

A total of 155 patients (110 in the training cohort and 45 in the testing cohort) with LAGC who had standard NAC before surgery were retrospectively enrolled. All CT images were analyzed by two radiologists for manual classification. Volumes of interests (VOIs) were delineated semi-automatically, and 1,226 radiomics features were extracted from every segmented lesion in both IM and 120 kVp images, respectively. Spearman's correlation analysis and the least absolute shrinkage and selection operator (LASSO) penalized logistic regression were implemented for filtering unstable and redundant features and screening out vital features. Two predictive models (120 kVp and IM-120 kVp) based on 120 kVp selected features only and 120 kVp combined with IM selected features were established by multivariate logistic regression analysis. We then build a combination model (ComModel) developed with IM-120 kVp signature and ycT. The performance of these three models and manual classification were evaluated and compared.

Result

Three radiomics models showed great predictive accuracy and performance in both the training and testing cohorts (ComModel: AUC: training, 0.953, testing, 0.914; IM-120 kVp: AUC: training, 0.953, testing, 0.879; 120 kVp: AUC: training, 0.940, testing, 0.831). All these models showed higher diagnostic accuracy (ComModel: 88.9%, IM-120 kVp: 84.4%, 120 kVp: 80.0%) than manual classification (68.9%) in the testing group. ComModel and IM-120 kVp model had better performances than manual classification both in the training (both p<0.001) and testing cohorts (p<0.001 and p=0.034, respectively).

Conclusions

Dual-energy CT-based radiomics models demonstrated convincible diagnostic performance in differentiating serosal invasion in preoperative restaging for LAGC. The radiomics features derived from IM showed great potential for improving the diagnostic capability.

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.

Oncologic feasibility of D1+ gastrectomy for patients with cT1N1, cT2N0-1, or cT3N0 gastric cancer

INTRODUCTION

D2 gastrectomy has shown a survival benefit in patients with highly advanced gastric cancer; however, it remains unclear whether D2 gastrectomy is required for patients with early-stage advanced gastric cancer or early gastric cancer with limited lymph node metastasis. This analysis aimed to clarify the oncologic feasibility of D1+ gastrectomy in patients with cT1N1, cT2N0-1, or cT3N0 gastric cancer.

METHODS

This retrospective cohort analysis included 466 patients with cT1N1, cT2N0-1, or cT3N0 gastric cancer who received curative gastrectomy with either D2 or D1+ dissection. Surgical outcomes were compared between the D2 group (n = 406) and the D1+ group (n = 60).

RESULTS

The number of patients with higher age and higher comorbidity index was greater in the D1+ group than in the D2 group. Postoperative complications were significantly lower in the D1+ group than in the D2 group (10.0% vs. 26.8%, p = 0.004). No statistically significant difference in 5-year overall survival (p = 0.146) and disease-specific survival (p = 0.807) between the groups was noted. The incidence of local recurrences (p = 0.500) and that of lymph node recurrences (p = 1.000) were also similar between the groups. Multivariable analysis for overall survival identified age, clinical node-positive status, high Charlson score (≥3), advanced pathological stage (≥III), and postoperative complication (grade ≥ II) as independent prognostic factors. The propensity score-matched analysis showed very similar survival outcomes between the groups.

CONCLUSION

D1+ gastrectomy may be oncologically feasible for patients with cT1N1, cT2N0-1, or cT3N0 stage gastric cancer.

Clinical significance of neutrophil-to-lymphocyte ratio as a predictor of lymph node metastasis in gastric cancer

Background

Precise staging is indispensable to select the appropriate treatment strategy for gastric cancer (GC); however, the diagnostic accuracy of conventional modalities needs to be improved. This study investigated the clinical significance of the preoperative neutrophil-to-lymphocyte ratio (NLR) for the prediction of pathological lymph node metastasis (pN+) in GC.

Methods

This was a retrospective study of 429 patients with GC who underwent curative gastrectomy. The predictive ability of NLR for pN+ was examined in comparison with that of computed tomography.

Results

The preoperative NLR ranged from 0.6 to 10.8 (median, 2.0), and the optimal cut-off value for predicting pN+ was 1.6 according to the receiver operating characteristic curve with the maximal Youden index. Multivariate analysis identified a NLR ≥ 1.6 (odds ratio (OR) 3.171; 95% confidence interval (CI) 1.448–7.235, p = 0.004) and cN+ (OR 2.426; 95% CI 1.221–4.958, p = 0.011) to be independent factors associated with pN+ in advanced GC (cT2-T4). On the other hand, a NLR ≥ 1.6 was not useful for predicting pN+ in early GC (cT1). In advanced GC, a NLR ≥ 1.6 detected pN+ with a higher sensitivity (84.9%) and negative predictive value (NPV) (63.9%) than conventional modalities (50.0 and 51.7%, respectively). When the subjects were limited to those with advanced GC with cN0, the sensitivity and NPV of a NLR ≥ 1.6 for pN+ increased further (90.7 and 81.0%, respectively).

Conclusion

The preoperative NLR may be a useful complementary diagnostic tool for predicting pN+ in advanced GC because of its higher sensitivity and NPV than conventional modalities.

Yield of staging laparoscopy in gastric cancer is influenced by Laurén histologic subtype

BACKGROUND

Staging laparoscopy (SL) with cytologic lavage is a useful staging procedure that allows tailoring the treatment of advanced gastric cancer (GC). The current study aimed to evaluate the total yield of SL in patients with various Laurén histo-types of GC, before planned neoadjuvant chemotherapy and gastrectomy.

METHODS

After exclusion of distant metastatic disease on imaging modalities, 173 patients with primary advanced gastric adenocarcinoma who underwent SL between August 2016 and September 2018, were eligible for the analysis. Patients sex, age, Lauren histo-type, tumor location, grade, cT, and cN were assessed in bivariate analysis. Multivariable logistic regression analysis was used to identify independent factors associated with peritoneal metastases.

RESULTS

Peritoneal metastases, ascites, and positive cytology were found in 39 (22.5%), 17 (9.8%) and 38 (22%) patients, respectively. The total yield of the SL in the current study was 36.4%. Multivariable logistic regression analysis revealed that serosal involvement (cT4) and diffuse histo-type were independent predictors of peritoneal metastases (OR, 15; 95% CI, 1.9-119, P = .02 and OR, 2.4; 95% CI, 1.2-4.6, P = .01, respectively).

CONCLUSIONS

Although cT4 and diffuse tumors show the highest association with peritoneal metastases, SL is a valuable diagnostic procedure in all advanced GC patients.

Can Preoperative Examination Help Choose the Best Surgical Procedure in Gastric Cancer?

Aim

Gastrectomy with lymph node dissection is standard treatment in gastric cancer. This study aimed to explore whether preoperative investigation finds could predict lymph node metastatic scope in gastric carcinoma so that the optimal surgical procedure could be selected.

Materials and Methods

Radical gastrectomy patients (n = 378) were separated into two groups according to the lymph node metastatic scope. Univariate and multivariate analyses of preoperative examination results were performed to identify the predictors of metastatic scope. ROC curves were constructed, and the area under the curve (AUC) was calculated to estimate diagnostic values.

Results

Serum CEA (OR: 3.73; 95% CI: 1.84–7.56; P ≤ 0.001), tumor size (OR: 2.07; 95% CI: 1.08–3.98; P = 0.03), and CT examination results (OR: 17.81; 95% CI: 9.18–34.55; P ≤ 0.001) were identified as independent predictors. The AUC proved that they possessed significant diagnostic value. When CT examination was negative, the combination of serum CEA and tumor size showed high specificity (95.3%; 164/172), negative predictive value (92.7%; 164/177), and accuracy (89.0%; 170/191).

Conclusions

Preoperative serum CEA, tumor size, and CT examination are independent predictors of lymph node metastatic scope and can be used for selecting the appropriate lymphadenectomy pattern in gastric cancer patients.

Value of Preoperative PET-CT in the Prediction of Pathological Stage of Gastric Cancer

BACKGROUND

Preoperative precise staging is essential for the treatment of gastric cancer (GC); however, the diagnostic accuracy of conventional modalities needs to be increased. The present study investigated the clinical value of positron emission tomography-computed tomography (PET-CT) for the staging of GC.

METHODS

This was a retrospective study of 117 patients with a clinical diagnosis of advanced GC who underwent PET-CT followed by gastrectomy. The incidence of FDG uptake in the primary tumor or lymph nodes and its relationship with clinicopathological factors, particularly pathological stage (pStage) III/IV, were examined.

RESULTS

FDG uptake in the primary tumor was noted in 83 patients (70.9%). FDG uptake in the lymph nodes was detected in 21 patients (17.9%), and its sensitivity and specificity for lymph node metastasis were 22.7 and 90.5%, respectively. Multiple logistic regression analyses showed that FDG uptake in the primary tumor (odds ratio (OR) 2.764; 95% confidence interval (CI) 1.104-7.459, p = 0.029) and that in the lymph nodes (OR 4.660; 95% CI 1.675-13.84, p = 0.003) were factors independently associated with pStage III/IV. FDG uptake in the primary tumor detected pStage III/IV with higher sensitivity (80.4%) and that in lymph nodes found pStage III/IV with higher specificity (88.7%) than those of upper endoscopy plus CT (60.9 and 67.6%, respectively).

CONCLUSIONS

PET-CT appears to be a useful complementary modality in the assessment of pStage III/IV because of the high sensitivity of FDG uptake in the primary tumor and the high specificity of FDG uptake in the lymph nodes.

Preoperative CT texture analysis of gastric cancer: correlations with postoperative TNM staging

AIM

To explore the role of computed tomography (CT) texture analysis in predicting pathologic stage of gastric cancers.

MATERIALS AND METHODS

Preoperative enhanced CT images of 153 patients (112 men, 41 women) with gastric cancers were reviewed retrospectively. Regions of interest (ROIs) were manually drawn along the margin of the lesion on the section where it appeared largest on the arterial and venous CT images, which yielded texture parameters, including mean, maximum frequency, mode, skewness, kurtosis, and entropy. Correlations between texture parameters and pathological stage were analysed with Spearman's correlation test. The diagnostic performance of CT texture parameters in differentiating different stages was evaluated using receiver operating characteristic (ROC) analysis.

RESULTS

Maximum frequency in the arterial phase and mean, maximum frequency, mode in the venous phase correlated positively with T stage, N stage, and overall stage (all p<0.05) of gastric cancer. Entropy in the venous phase also correlated positively with N stage (p=0.009) and overall stage (p=0.032). Skewness in the arterial phase had the highest area under the ROC curve (AUC) of 0.822 in identifying early from advanced gastric cancers. Multivariate analysis identified four parameters, including maximum frequency, skewness, entropy in the venous phase, and differentiation degree from biopsy, for predicting lymph node metastasis of gastric cancer. The multivariate model could distinguish gastric cancers with and without lymph node metastasis with an AUC of 0.892.

CONCLUSION

Multiple CT texture parameters, especially those in the venous phase, correlated well with pathological stage and hold great potential in predicting lymph node metastasis of gastric cancers.

Feasibility of differentiating T3 from T4a gastric cancer in different Lauren classification by determining serosa invasion: Diagnostic performance of high enhanced serosa sign

Objective

To study the value of high enhanced serosa sign on contrast-enhanced computed tomography (CT) in differentiating T3 from T4a gastric cancer in different Lauren classification.

Methods

This study included 276 consecutive patients with surgically confirmed pT3 or pT4a gastric cancers. The pre-operative CT images were reviewed by two radiologists blinded. The demonstration of the high enhanced serosa on CT between T3 and T4a was compared with chi-square test. The diagnostic performance of this sign on CT in the differentiation of T4a from T3 in different Lauren classification was calculated.

Results

The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the judgement of serosa invasion using the high enhanced serosa sign on CT was 74.6%, 63.7%, 83.6%, 76.0% and 73.8% by one radiologist and 76.4%, 66.1%, 84.9%, 78.1% and 75.4% by the other radiologist. Compared to the intestinal-type, the sensitivity of the judgement of serosa invasion using the high enhanced serosa sign on CT in diffuse-type was significant higher (80% in both readers), while the specificity trended to be lower (65.9% and 80.5%, respectively). There is no significant difference in the accuracy of diagnosis between intestinal-type and diffuse-type of gastric cancers (the P-values of two radiologists were 0.968, 0.591, respectively). The combination of the high enhanced serosa sign with conventional CT signs is significant different in diagnosis of T3 and T4a (P<0.001). The diagnostic accuracy was increased in both radiologists after the combination. The two readers achieved substantial agreement, with Kappa coefficient of 0.63, P<0.001.

Conclusions

The high enhanced serosa sign on CT is associated with serosa involvement. The sensitivity of the judgement of serosa invasion using this sign on CT in diffuse-type was significant higher than that in intestinal-type.

Value and impact factors of multidetector computed tomography in diagnosis of preoperative lymph node metastasis in gastric cancer: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Multidetector computed tomography (MDCT) exhibited wide ranges of sensitivities and specificities for lymph node assessment of gastric cancer (GC) in several individual studies. This present meta-analysis was carried out to evaluate the value of MDCT in diagnosis of preoperative lymph node metastasis (LNM) and to explore the impact factors that might explain the heterogeneity of its diagnostic accuracy in GC.

METHODS

A comprehensive search was conducted to collect all the relevant studies about the value of MDCT in assessing LNM of GC within the PubMed, Cochrane library and Embase databases up to Feb 2, 2016. Two investigators independently screened the studies, extracted data, and evaluated the quality of included studies. The sensitivity, specificity, and area under ROC curve (AUC) were pooled to estimate the overall accuracy of MDCT. Meta-regression and subgroup analysis were carried out to identify the possible factors influencing the heterogeneity of the accuracy.

RESULTS

A total of 27 studies with 6519 subjects were finally included. Overall, the pooled sensitivity, specificity, and AUC were 0.67 (95% CI: 0.56-0.77), 0.86 (95% CI: 0.81-0.90), and 0.86 (95% CI: 0.83-0.89), respectively. Meta-regression revealed that MDCT section thickness, proportion of serosal invasion, and publication year were the main significant impact factors in sensitivity, and MDCT section thickness, multiplanar reformation (MPR), and reference standard were the main significant impact factors in specificity. After the included studies were divided into 2 groups (Group A: studies with proportion of serosa-invasive GC subjects ≥50%; Group B: studies with proportion of serosa-invasive GC subjects <50%), the pooled sensitivity in Group A was significantly higher than in Group B (0.84 [95% CI: 0.75-0.90] vs 0.55 [95% CI: 0.41-0.68], P < .01). For early gastric cancer (EGC), the pooled sensitivity, specificity, and AUC were 0.34 (95% CI: 0.15-0.61), 0.91 (95% CI: 0.84-0.95), and 0.83 (95% CI: 0.80-0.86), respectively.

CONCLUSION

To summarize, MDCT tends to be adequate to assess preoperative LNM in serosa-invasive GC, but insufficient for non-serosa-invasive GC (particularly for EGC) owing to its low sensitivity. Proportion of serosa-invasive GC subjects, MDCT section thickness, MPR, and reference standard are the main factors influencing its diagnostic accuracy.

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.

Accuracy of Multidetector-Row Computed Tomography in the Preoperative Diagnosis of Lymph Node Metastasis in Patients with Gastric Cancer

BACKGROUND/AIMS

Preoperative lymph node staging in gastric cancer patients is important. The aim of this study was to assess the diagnostic accuracy of computed tomography (CT) in assessing lymph nodes in patients with gastric cancer.

METHODS

A total of 56 patients had undergone standardized gastric resection with lymphadenectomy between October 2013 and June 2015 were reviewed retrospectively. The short axis diameter of the largest lymph node per station was recorded when reviewing the preoperative CT images. Diagnostic accuracy was calculated by comparing CT with histopathological findings.

RESULTS

In 518 stations dissected at surgery, 56 included lymph nodes with metastasis. Among them, lymph nodes were visualized on preoperative CT in 26 stations. No lymph node was detected in 382 stations among 462 infiltration-negative stations. The cutoff of 12 mm had the highest accuracy rate of 0.896.

CONCLUSION

The accuracy of CT in the preoperative diagnosis of lymph node metastasis in patients with gastric cancer remains poor. Therefore, surgeons should pay attention to the visibility of lymph nodes on CT. Detection of lymph nodes on CT can be utilized for a more accurate diagnosis such as fine-needle aspiration biopsy.

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.

Evaluation of 64-Channel Contrast-Enhanced Multi-detector Row Computed Tomography for Preoperative N Staging in cT2-4 Gastric Carcinoma

BACKGROUND

Preoperative N staging is essential for the best treatment planning in patients with gastric carcinoma. The aim of this study was to evaluate the accuracy of preoperative N staging using contrast-enhanced multi-detector row computed tomography (CE-MDCT) in patients with resectable cT2-4 gastric carcinoma.

METHODS

A total of 218 patients who underwent a gastrectomy with D2 lymphadenectomy for previously untreated cT2-4 primary gastric carcinoma were studied. Preoperative N staging was performed according to the 7th (UICC) TNM Staging System using pre-specified criteria on a 64-channel CE-MDCT and was compared with postoperative pathologic N staging.

RESULTS

In all 218 patients, a distal or total gastrectomy was performed. The overall accuracy of the preoperative N staging was 46.3% (101/218), with the proportion of over- and under-staging being 26.6% (58/218) and 27.1% (59/218), respectively. The sensitivity, specificity, and accuracy for lymph node metastasis (≥pN1) were 79.1% (106/134), 50.0% (42/84), and 67.9% (148/218), respectively. The sensitivity, specificity, and accuracy for multiple lymph node metastases (≥pN2) were 80.2% (73/91), 68.5% (87/127), and 73.4% (160/218), respectively. Multivariate analyses showed that macroscopic type 2 and ≥6 cm-sized tumors were associated with preoperative over-N staging, while macroscopic type 1/3 tumors were associated with under-N staging.

CONCLUSION

Preoperative N staging with pinpoint accuracy is difficult. However, CE-MDCT offers a reasonably high sensitivity and specificity for ≥pN2 and may be useful for selecting candidates for neoadjuvant therapies. The macroscopic type and size of the primary tumor may affect the accuracy of preoperative N staging.

Survival results of a randomised two-by-two factorial phase II trial comparing neoadjuvant chemotherapy with two and four courses of S-1 plus cisplatin (SC) and paclitaxel plus cisplatin (PC) followed by D2 gastrectomy for resectable advanced gastric cancer

BACKGROUND

The prognosis for stage III gastric cancer is unsatisfactory by D2 gastrectomy and S-1 adjuvant chemotherapy. Both S-1 plus cisplatin (SC) and paclitaxel plus cisplatin (PC) are promising regimens as neoadjuvant chemotherapy; however, the optimal duration remains unclear.

PATIENTS AND METHODS

In this 2×2 randomised phase II trial, stage III gastric cancer patients, those with a prognosis corresponding to stage III, and macroscopically resectable stage IV cases were randomised to two or four courses of S-1 (80 mg/m(2) for 21 d with 1 week rest)/cisplatin (60 mg/m(2) at day 8) or PC (80 and 25 mg/m(2), respectively, on days 1, 8, and 15 with 1 week rest) as neoadjuvant chemotherapy. The primary end-point was the 3-year overall survival (OS).

RESULTS

Between October 2009 and July 2011, 83 patients received 2 courses of SC (n=21), 4 courses of SC (n=20), 2 courses of PC (n=21) and 4 courses of PC (n=21). The 3-year OS was 60.9% for SC and 64.3% for PC and 64.3% for the two courses and 61.0% for the four courses. Subset analyses demonstrated no subgroup which showed any potential survival benefit by PC in comparison to SC or by four courses as in comparison to two courses.

CONCLUSIONS

Two courses of SC as neoadjuvant chemotherapy are recommended as a test arm of a future phase III study for patients with locally advanced gastric cancer.

CLINICAL TRIAL NUMBER

UMIN-000002595.

Gastric Cancer: Preoperative TNM Staging With Individually Adjusted Computed Tomography Scanning Phase

OBJECTIVE

The aim of this study was to evaluate test bolus scan technology on preoperative diagnostic performance, vascular enhancement, and artery visualization for gastric cancer.

METHODS

The institutional review board approved this study. Fifty-four patients in protocol 1 were resigned to a fixed delay time scan method, and their images were obtained in the late arterial phase (AP) and portal venous phase (PP), with start delays of 40 and 70 seconds, respectively. Fifty-six patients in protocol 2 had undergone the test bolus method first and received the time to peak enhancement of the aorta. Their images were obtained in the AP and PP with start delays in the time to peak enhancement and 20 seconds after the AP, respectively. Two radiologists performed consensus interpretation of the preoperative TNM staging, vascular enhancement, tumor contrast-to-noise ratio (CNR) and artery visualization between the 2 protocols.

RESULTS

There is no significant difference in the T, N, and M staging diagnostic accuracy between the protocols (P = 0.41, P > 0.99, and P = 0.34, respectively). For serosa-negative (T1, T2, and T3) tumors, the diagnostic accuracy obtained with protocol 2 was superior to that obtained with protocol 1 (P = 0.04). Protocol 2 was superior for perigastric vessel enhancement (left gastric artery, right gastroepiploic artery, and splenic artery; P < 0.001, P < 0.001, and P = 0.001, respectively). The stomach-to-tumor CNR during the PP of protocol 2 was significantly higher than that during either the AP or PP of protocol 1 (P = 0.004 and P = 0.001, respectively). The mean rankings of the artery visualization were significantly higher with protocol 2 than with protocol 1 (P < 0.001).

CONCLUSIONS

The dual-phase scan with test bolus technology could improve the tumor CNR and had high staging accuracy for serosa-negative tumors as well as high perigastric artery enhancement, yielding satisfactory artery visualization for diagnosis.

Pretreatment Neutrophil to Lymphocyte Ratio Independently Predicts Disease-specific Survival in Resectable Gastroesophageal Junction and Gastric Adenocarcinoma

OBJECTIVE

Preoperative methods to estimate disease-specific survival (DSS) for resectable gastroesophageal (GE) junction and gastric adenocarcinoma are limited. We evaluated the relationship between DSS and pretreatment neutrophil to lymphocyte ratio (NLR).

BACKGROUND

The patient's inflammatory state is thought to be associated with oncologic outcomes, and NLR has been used as a simple and convenient marker for the systemic inflammatory response. Previous studies have suggested that NLR is associated with cancer-specific outcomes.

METHODS

A retrospective review of a prospectively maintained institutional database was undertaken to identify patients who underwent potentially curative resection for GE junction and gastric adenocarcinoma from 1998 to 2013. Clinicopathologic findings, pretreatment leukocyte values, and follow-up status were recorded. The Kaplan-Meier method was used to estimate DSS, and Cox proportional hazards models were used to evaluate the association between variables and DSS.

RESULTS

We identified 1498 patients who fulfilled our eligibility criteria. Univariate analysis showed that male sex, Caucasian race, increased T and N stage, GE junction location, moderate/poor differentiation, nonintestinal Lauren histology, and vascular and perineural invasion were associated with worse DSS. Elevated NLR was also associated with worse DSS [hazard ratio (HR) = 1.11; 95% CI: 1.08-1.14; P < 0.01]. On multivariate analysis, pretreatment NLR as a continuous variable was a highly significant independent predictor of DSS. For every unit increase in NLR, the risk of cancer-associated death increases by approximately 10% (HR = 1.10; 95% CI: 1.05-1.13; P < 0.0001).

CONCLUSIONS

In patients with resectable GE junction and gastric adenocarcinoma, pretreatment NLR independently predicts DSS. This and other clinical variables can be used in conjunction with cross-sectional imaging and endoscopic ultrasound as part of the preoperative risk stratification process.

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.

Clinical significance and prognostic impact of the total diameter of enlarged lymph nodes on preoperative multidetector computed tomography in patients with gastric cancer

BACKGROUND AND AIM

This study was designed to evaluate the clinical significance and prognostic impact of the total diameter of enlarged lymph nodes (TDL) on preoperative multidetector computed tomography (MDCT) in gastric cancer (GC).

METHODS

Of a total of 480 GC patients between 2005 and 2009, 70 patients with a preoperative diagnosis of nodal metastasis on MDCT were included in this study. All regional lymph nodes showing metastatic involvement were preoperatively counted and measured.

RESULTS

The TDL was calculated, and using a receiver operating characteristic curve, a cutoff value of 45 mm in the two groups of large TDL (LTDL) and small TDL was found to be appropriate for TDL. No significant differences were observed in clinicopathological features, except for tumor recurrence, between the two groups. Univariate survival analysis revealed that patients with LTDL had a worse prognosis as well as an upper tumor location, deeper tumor depth, and further advanced pathological stage. Multivariable prognostic analysis identified LTDL as an independent worse prognostic factor (P = 0.0128).

CONCLUSIONS

GC patients with the total nodal diameter measuring 45 mm or more on MDCT have a worse prognosis. GC patients with the novel surrogate indicator of worse prognosis for a preoperative imaging diagnosis may have need of multimodal treatment to improve the survival.

Accuracy of EUS and CT imaging in preoperative gastric cancer staging

BACKGROUND

Neoadjuvant therapy is recommended for locally advanced gastric cancer patients (stage IB-IIIC). The objective of this study is to evaluate the accuracy of endoscopic ultrasound (EUS) and computed tomography (CT) in identifying patients with locally advanced gastric cancer.

METHODS

Patients with gastric adenocarcinoma who underwent gastrectomy at our institution were reviewed. Preoperative EUS and CT staging were compared with pathologic staging to determine accuracy.

RESULTS

Between 2001 and 2013, 280 patients were identified. Forty-nine patients (18%) who underwent preoperative staging by EUS were analyzed. The accuracy of EUS in identifying individual T stage and N stage was 41.0% and 42.9%, respectively. EUS had moderate accuracy in differentiating locally advanced from early (stage 0-IA) disease (75.5%, area under curve (AUC) 0.772). For individual T stage and N stage, the accuracy of CT was 4.0% and 56%, respectively. CT had relatively poor accuracy in differentiating locally advanced from early disease (60.0%, AUC 0.649).

CONCLUSIONS

EUS and CT had poor performance in identifying individual T and N stage although EUS demonstrated moderate accuracy in identifying patients with locally advanced disease. A combined staging approach, in addition to further optimization of staging modalities, is required for accurate staging for patients with gastric cancer.

Long-term survival outcomes of advanced gastric cancer patients who achieved a pathological complete response with neoadjuvant chemotherapy: a systematic review of the literature

BACKGROUND

A pathologic complete response (pCR) can sometimes be induced by intensive or long-term neoadjuvant chemotherapy (NAC). This prognostic research study based on a systematic review of the literature evaluated the impact of a pCR on the long-term survival of gastric cancer (GC) patients.

METHODS

Articles were extracted from PubMed and the Japanese medical search engine "Ichu-shi," using the terms "GC," "NAC," and "pCR." Articles were selected based on the following criteria: (1) full-text case report, (2) R0 resection following NAC for locally advanced GC, and (3) pathological complete response in both the primary stomach and in the lymph nodes. A questionnaire regarding the patients' prognoses was sent to the corresponding authors of the articles selected in July 2013.

RESULTS

Twenty-four articles met the criteria. Twenty authors responded to the questionnaire. Finally, 22 patients from 20 articles were entered into the present study. The median follow-up time (range) of the survivors was 76 (range 13-161) months. Tumors that were stage III/IV (86%: 19/22) and of an undifferentiated histology (61.9%: 13/21) were dominant. An S1-based regimen was frequently selected for the NAC. All patients underwent R0 resection and D2/D3 lymphadenectomy. The overall survival and recurrence-free survival rates at 3 and 5 years were 96% and 85% and 91% and 75%, respectively.

CONCLUSIONS

Although a pCR was a relatively rare event, a high pCR rate would be helpful to select the regimen and courses of NAC, especially when the pathological response rates are similar.

Effect of neoadjuvant chemotherapy on postoperative morbidity and mortality in patients with locally advanced gastric cancer

BACKGROUND

Neoadjuvant chemotherapy has been shown to improve the rate of complete (R0) resection and downstaging in patients with localized gastric cancer. There are few reports, however, regarding its impact on postoperative morbidity and mortality. The aims of this study were to analyse complication and mortality rates after neoadjuvant chemotherapy using a modified regimen of folinic acid, 5-fluorouracil and oxaliplatin (mFOLFOX6) for locally advanced gastric cancer (AGC), compared with rates in patients who underwent surgery without neoadjuvant chemotherapy.

METHODS

Data were collected from patients with AGC enrolled in a phase II trial of four cycles of neoadjuvant mFOLFOX6 followed by surgery, between January 2005 and June 2008 at two of three institutions, and compared with those from a cohort of patients with AGC who underwent surgery alone at one of the institutions in 2006.

RESULTS

Among 51 patients who received neoadjuvant chemotherapy, there were no deaths and a morbidity rate of 24 per cent after surgery. Comparison of 48 patients in one institution who received neoadjuvant chemotherapy with 92 patients who had surgery alone in the same institution showed no increase in postoperative morbidity (23 versus 29 per cent; P = 0·417). Combined resection was the only risk factor for postoperative morbidity after neoadjuvant chemotherapy.

CONCLUSION

Neoadjuvant chemotherapy with mFOLFOX is a safe treatment for patients with localized AGC, and does not increase postoperative morbidity or mortality.

Gastric adenocarcinoma with para-aortic lymph node metastasis: a borderline resectable cancer?

Dissection of the para-aortic lymph nodes (PAN) had once been enthusiastically explored at dedicated centers throughout Japan. Reflecting the results of a randomized trial, however, the current standard surgery for advanced resectable gastric cancer does not include systematic dissection of the PAN. Gastric cancer with PAN metastases, currently considered distant metastases, is classified as Stage IV, and according to the algorithm of the Japanese guidelines, is not indicated for surgery with curative intent. Historical data indicates, however, that a certain proportion of long-term survivors can be introduced among patients with PAN metastasis through D2 + PAN dissection. The Japan Clinical Oncology Group launched a series of phase II trials exploring a strategy employing neoadjuvant chemotherapy followed by D2 + PAN dissection for patients radiologically diagnosed to harbor metastases to the PAN. The campaign was successful, with 57% of these patients surviving for 5 years after two cycles of neoadjuvant S-1/CDDP followed by surgery. This strategy is now the tentative standard, mentioned in the 4th version of the Japanese Gastric Cancer Treatment Guidelines as one of the current clinical questions, and could be replaced by a more powerful combination chemotherapy or treatment employing more or longer cycles of chemotherapy in the future. The relevance of the strategy consisting of neoadjuvant chemotherapy followed by D2 + PAN dissection and its fundamental difference from the concept of conversion therapy are discussed herein with reference to the literature.

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.

Robotic spleen-preserving total gastrectomy for gastric cancer: comparison with conventional laparoscopic procedure

BACKGROUND

Robotic systems recently have been introduced to overcome technical limitations of conventional laparoscopic surgery, especially for complex procedures. Laparoscopic spleen-preserving total gastrectomy with D2 lymph node (LN) dissection (LTGD2) is one of the most complicated procedures. We hypothesized that robotic LN dissection would be more thorough and accurate. We compared robotic spleen-preserving total gastrectomy with D2 LN dissection (RTGD2) with LTGD2 to investigate the impact of robotics.

METHODS

Clinicopathologic characteristics and short-term and long-term outcomes of RTGD2 (n = 51) versus LTGD2 (n = 58) in gastric adenocarcinoma patients were extracted from a prospectively designed database and analyzed retrospectively.

RESULTS

There was no difference of patients' characteristics between groups. Mean operation time of RTGD2 was longer than LTGD2 (p < 0.001), and no differences in tumor histology, size, location, and TNM stage were seen. Total retrieved LNs from RTGD2 was similar to LTGD2 (mean 47.2 vs. 42.8, respectively), as were retrieved LNs at splenic hilum (1.3 vs. 0.8). However, mean numbers of retrieved LNs along the splenic artery from RTGD2 was higher than LTGD2 (2.3 vs. 1.0, respectively; p = 0.013), as was also the case at the splenic hilum and artery (3.6 vs. 1.9, p = 0.014). Postoperative complication (16 vs. 22 %, p = 0.374) and overall and disease-free survival between the two groups were not significantly different (p = 0.767 and p = 0.666, respectively).

CONCLUSIONS

Robotic spleen-preserving total gastrectomy with D2 LN dissection is feasible. Operation time and retrieved total LNs and splenic hilar LNs in the robotic procedure are acceptable.

Diagnostic value of computed tomography for staging of clinical T1 gastric cancer

BACKGROUND

T1 gastric cancer can be diagnosed only by endoscopy and is almost curable by local treatment. It has been unclear how a multidetector-row computed tomography (CT) evaluation is valuable for clinical T1 patients.

METHODS

Patients with clinical T1 disease, as diagnosed by endoscopy and treated with endoscopic submucosal dissection (ESD) or surgery between October 2000 and October 2007, were examined. The efficacy of CT was evaluated by the reversal rate of endoscopic T1 by CT, the incidence of clinical M1 disease, and the accuracy of diagnosing pathological N+ disease in patients who received surgery. To confirm metachronous distant and nodal metastases, the disease-free survival (DFS) also was evaluated.

RESULTS

A total of 761 patients, 236 treated by ESD and 525 treated with surgery, were examined. None of the patients had an endoscopic diagnosis of clinical T1 reversed by CT. No clinical M1 disease was found. Among the 525 patients who underwent surgery, 8 showed clinical N+ disease (1.5 %), while 47 demonstrated pathological N+ disease (8.9 %). The accuracy, sensitivity, specificity, positive predictive value, and negative predictive values were 90.3, 4.3, 98.7, 25, and 91.3 %, respectively. The 5-year DFS rate was 93.6 % (95 % confidence interval 91.4-95.8 %).

CONCLUSIONS

The present study suggests that diagnostic value of CT is limited for staging of clinical T1 gastric cancer patients, because the reversal rate of endoscopic T1 by CT was very low, clinical M1 disease was rare, the diagnosis of N+ status was unreliable, and metachronous M1 and N+ findings were rare.

Accuracy of CT staging of locally advanced gastric cancer after neoadjuvant chemotherapy: cohort evaluation within a randomized phase II study

BACKGROUND

Accuracy of the radiologic diagnosis of gastric cancer staging after neoadjuvant chemotherapy remains unclear.

METHODS

Patients enrolled in the COMPASS trial, a randomized phase II study comparing two and four courses of S-1 plus cisplatin and paclitaxel and cisplatin followed by gastrectomy, were examined. The radiologic stage was determined by using thin-slice computed tomography (CT) or multidetector low CT by following Habermann's method.

RESULTS

A total of 75 patients registered in the COMPASS study who underwent surgical resection were examined in this study. The radiologic T and pathologic T stages were not significantly correlated (p = 0.221). The radiologic accuracy and rates of underdiagnosis and overdiagnosis were 42.7, 10.7, and 46.7%, respectively. When patients were stratified according to the pathologic response of the primary tumor, the correlation was not significant in either the responders (n = 32, p = 0.410) or the nonresponders (n = 43, p = 0.742). The radiologic accuracy was 37.5% in the responders and 42.7% in the nonresponders. The radiologic N and pathologic N stages were significantly correlated (p = 0.000). The radiologic accuracy and rates of underdiagnosis and overdiagnosis were 44, 29.3, and 26.7%, respectively. When stratifying the patients with measurable lymph nodes according only to the radiologic response, the correlation was significant in the nonresponders (n = 23, p = 0.035) but not in the responders (n = 28, p = 0.634). The radiologic accuracy was 39.3% in the responders and 52.1% in the nonresponders.

CONCLUSIONS

Restaging using CT after neoadjuvant chemotherapy for gastric cancer is considered to be inaccurate and unreliable. In particular, the radiologic T-staging determined after neoadjuvant chemotherapy should not be considered in clinical decision-making.