Prognostic significance of level and number of lymph node metastases in patients with gastric cancer

Worse Survival of Patients With T1 Stage II Gastric Cancer Following Radical Gastrectomy

PURPOSE

Lymph node (LN) metastasis is a crucial factor in the prognosis of patients with gastric cancer (GC) and is known to occur more frequently in cases with an advanced T stage. This study aimed to analyze the survival data of patients with advanced LN metastasis in T1 GC.

MATERIALS AND METHODS

From January 2008 to June 2018, 677 patients with pathological stage II GC who underwent radical gastrectomy were divided into an early GC group (EG: T1N2 and T1N3a, n=103) and an advanced GC (AGC) group (AG: T2N1, T2N2, T3N0, T3N1, and T4aN0, n=574). Short- and long-term survival rates were compared between the 2 groups.

RESULTS

A total of 80.6% (n=83) of the patients in the EG group and 52.8% (n=303) in the AG group had stage IIA AGC. The extent of LN dissection, number of retrieved LNs, and short-term morbidity and mortality rates did not differ between the 2 groups. The 5-year relapse-free survival (RFS) of all patients was 87.8% and the overall survival was 84.0%. RFS was lower in the EG group than in the AG group (82.2% vs. 88.7%, P=0.047). This difference was more pronounced among patients with stage IIA (82.4% vs. 92.9%, P=0.003).

CONCLUSIONS

T1 GC with multiple LN metastases seems to have a worse prognosis compared to tumors with higher T-stages at the same level. Adjuvant chemotherapy is highly recommended for these patients, and future staging systems may require upstaging T1N2-stage tumors.

Mapping Lymph Node during Indocyanine Green Fluorescence-Imaging Guided Gastric Oncologic Surgery: Current Applications and Future Directions

Huge strides have been made in the navigation of gastric cancer surgery thanks to the improvement of intraoperative techniques. For now, the use of indocyanine green (ICG) enhanced fluorescence imaging has received promising results in detecting sentinel lymph nodes (SLNs) and tracing lymphatic drainages, which make it applicable for limited and precise lymphadenectomy. Nevertheless, issues of the lack of specificity and unpredictable false-negative lymph nodes were encountered in gastric oncologic surgery practice using ICG-enhanced fluorescence imaging (ICG-FI), which restrict its application. Here, we reviewed the current application of ICG-FI and assessed potential approaches to improving ICG-FI.

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.

Clinical Application of Indocyanine Green Fluorescence Technology in Laparoscopic Radical Gastrectomy

Background

This study aimed to observe the application and evaluate the feasibility and safety of indocyanine green (ICG) fluorescence technology in laparoscopic radical gastrectomy (LRG).

Methods

Patients who underwent LRG & D2 lymphadenectomy at Qilu Hospital of Shandong University were included between January 2018 and August 2019. According to whether endoscopic injection of ICG was performed, patients were assigned to the ICG group (n=107) and the control group (n=88). The clinicopathologic features, retrieved lymph nodes, postoperative recovery, and follow-up data were compared between the two groups.

Results

Baseline characteristics are comparable. The ICG group had a significantly larger number of lymph nodes retrieved (49.55 ± 12.72 vs. 44.44 ± 10.20, P<0.05), shorter total operation time (min) (198.22 ± 13.14 vs. 202.50 ± 9.91, P<0.05), shorter dissection time (min) (90.90 ± 5.34 vs. 93.74 ± 5.35, P<0.05) and less blood loss (ml) (27.51 ± 12.83 vs. 32.02 ± 17.99, P<0.05). The median follow-up time was 29.0 months (range 1.5-43.8 months), and there was no significant difference between the ICG group and the control group in 2-year OS (87.8% vs. 82.9%, P>0.05) or DFS (86.0% vs. 80.7%, P>0.05).

Conclusions

ICG fluorescence technology in laparoscopic radical gastrectomy has advantages in LN dissection, operation time, and intraoperative blood loss. The 2-year OS and 2-year DFS rates between the two groups were comparable. In conclusion, ICG fluorescence technology is feasible and safe.

An Immune-Related Gene Panel for Preoperative Lymph Node Status Evaluation in Advanced Gastric Cancer

Background and Aim: Gastric cancer (GC) is the common leading cause of cancer-related death worldwide. Immune-related genes (IRGs) may potentially predict lymph node metastasis (LNM). We aimed to develop a preoperative model to predict LNM based on these IRGs. Methods: In this paper, we compared and evaluated three machine learning models to predict LNM based on publicly available gene expression data from TCGA-STAD. The Pearson correlation coefficient (PCC) method was utilized to feature selection according to its relationships with LN status. The performance of the model was assessed using the area under the curve (AUC) and F1 score. Results: The Naive Bayesian model showed better performance and was constructed based on 26 selected gene features, with AUCs of 0.741 in the training set and 0.688 in the test set. The F1 score in the training set and test set was 0.652 and 0.597, respectively. Furthermore, Naive Bayesian model based on 26 IRGs is the first diagnostic tool for the identification of LNM in advanced GC. Conclusion: These results indicate that our new methods have the value of auxiliary diagnosis with promising clinical potential.

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.

Effect of Surgical Approach on Node Harvest in Robotic Gastrectomy

There has been increasing utilization of minimally invasive surgical approaches. This study evaluates the effect of surgical approach on total lymph node harvest in gastrectomy. Patients undergoing gastrectomy for gastric adenocarcinoma between 2007 and 2018 were reviewed retrospectively. Data collected included age, gender, race, BMI, neoadjuvant therapy, tumor stage, surgical approach, and total number of lymph nodes harvested. The total number of harvested lymph nodes for open, laparoscopic, and robotic gastrectomy was compared using the Kruskal-Wallis test for univariate analysis and a Poisson regression model for multivariable analysis. One hundred four patients were identified. Median node harvest for open, laparoscopic, and robotic approaches were 16, 17, and 36, respectively. Multivariable analysis controlling for gender, BMI, pathological T stage, and year of operation demonstrates that surgical approach is statistically significantly associated with lymph node harvest ( F = 83.4, P < 0.0001). In multivariable analysis, robotic approach was associated with greater lymph node harvest than both open ( P < 0.0001) and laparoscopic ( P < 0.0001) approaches, whereas laparoscopic approach was associated with greater lymph node harvest than open ( P < 0.0001) approach. These data demonstrate that for patients undergoing gastrectomy for gastric adenocarcinoma at our institution, robotic approach is associated with greater lymph node harvest than both laparoscopic and open approaches.

Recurrence outcome of lymph node ratio in gastric cancer after underwent curative resection: A retrospective cohort study

Introduction

D2 dissection has been regarded as the standard procedure for locally advanced gastric cancer (GC). Number of lymph nodes (LN) harvested is an important factor for accurate staging. The number of LN retrieved and the metastasis LN status are also important factors to determine the prognosis. This study aims to evaluate whether lymph node ratio (LNR) could be a prognostic indicator of GC patients following curative resection.

Patients and methods

Single center retrospective cohort study of GC patients underwent curative resection from January 1995 to December 2016 was conducted. The patients were categorized into 3 groups based on LNR (0.00-0.35, >0.35-0.75, and >0.75-1.00) and 2 groups based on number of LN retrieved (<15 and ≥ 15). Kaplan-Meier method was used to estimate recurrence-free survival. Cox-regression were used to determine the association between LNR/other factors and the disease recurrence.

Results

One-hundred fifty-three patients were included in analysis. Univariate analysis showed that LNR >0.35, pathologic LN stages (pN) 2-3, higher number of LN metastasis, and TNM stage III were significantly recurrence risk factors. After adjusting for several covariates, LNR >0.35 still was significant predictor (adjusted HR [95%CI], 8.53 [1.97, 36.86]; p = 0.004) while number of LN retrieved or number of metastasis LN were not.

Conclusion

LNR could be a strong indicator for the recurrence of GC after curative resection while the number of LN retrieved or metastasis did not predict the recurrence. Future studies, such as prospective studies, are needed to confirm and identify the optimum LNR cut-off.

Dual-energy CT-based deep learning radiomics can improve lymph node metastasis risk prediction for gastric cancer

OBJECTIVES

To build a dual-energy CT (DECT)-based deep learning radiomics nomogram for lymph node metastasis (LNM) prediction in gastric cancer.

MATERIALS AND METHODS

Preoperative DECT images were retrospectively collected from 204 pathologically confirmed cases of gastric adenocarcinoma (mean age, 58 years; range, 28-81 years; 157 men [mean age, 60 years; range, 28-81 years] and 47 women [mean age, 54 years; range, 28-79 years]) between November 2011 and October 2018, They were divided into training (n = 136) and test (n = 68) sets. Radiomics features were extracted from monochromatic images at arterial phase (AP) and venous phase (VP). Clinical information, CT parameters, and follow-up data were collected. A radiomics nomogram for LNM prediction was built using deep learning approach and evaluated in test set using ROC analysis. Its prognostic performance was determined with Harrell's concordance index (C-index) based on patients' outcomes.

RESULTS

The dual-energy CT radiomics signature was associated with LNM in two sets (Mann-Whitney U test, p < 0.001) and an achieved area under the ROC curve (AUC) of 0.71 for AP and 0.76 for VP in test set. The nomogram incorporated the two radiomics signatures and CT-reported lymph node status exhibited AUCs of 0.84 in the training set and 0.82 in the test set. The C-indices of the nomogram for progression-free survival and overall survival prediction were 0.64 (p = 0.004) and 0.67 (p = 0.002).

CONCLUSION

The DECT-based deep learning radiomics nomogram showed good performance in predicting LNM in gastric cancer. Furthermore, it was significantly associated with patients' prognosis.

KEY POINTS

• This study investigated the value of deep learning dual-energy CT-based radiomics in predicting lymph node metastasis in gastric cancer. • The dual-energy CT-based radiomics nomogram outweighed the single-energy model and the clinical model. • The nomogram also exhibited a significant prognostic ability for patient survival and enriched radiomics studies.

Carboxyl-, sulfonyl-, and phosphate-terminal dendrimers as a nanoplatform with lymph node targeting

The development of drug delivery vehicles to cancer and/or immune cells in lymph nodes is important for cancer diagnosis, therapy, and immunotherapy. We previously reported that anionic carboxyl-terminal dendrimers were accumulated in lymph nodes. In this study, three anionic dendrimers with carboxyl-, sulfonyl-, and phosphate-terminal groups were prepared to examine the lymph node targeting and the association with immune cells in the lymph nodes. These anionic dendrimers were accumulated in the lymph node by intradermal injection. Although the carboxyl- and sulfonyl-terminal dendrimers were diffused from the injection site, the phosphate-terminal dendrimers were mostly retained. The phosphate-terminal dendrimer was recognized by the macrophages, dendritic cells, and B cells in the lymph node, whereas the carboxyl- and sulfonyl-terminal dendrimers were not. Our results show that these anionic dendrimers were accumulated in the lymph node where the association with immune cells could be controlled by the terminal structure of the dendrimer. The phosphate-terminal dendrimer can be used as a nanoplatform for the delivery of some bioactive molecules to some immune cells, including B cells, in the lymph node.

Negative lymph node count as an independent prognostic factor in stage III patients after curative gastrectomy: A retrospective cohort study based on a multicenter database

OBJECTIVE

To examine the prognostic value of negative lymph node (NLN) count in stage III gastric cancer (GC) patients after curative gastrectomy.

METHODS

The clinicopathological data of 2942 stage III patients who underwent curative gastrectomy between 2001 and 2011 were analyzed. Only patients with ≥16 examined lymph nodes (ELNs) were included. After cut-point survival analysis, the 2942 patients were divided into three subgroups with NLN counts of 0, 1-9, and ≥10. Survival differences among the subgroups were analyzed to assess the effects of NLN count on stage migration and overall survival (OS) in stage III GC patients. Spearman's correlation coefficient was used to assess the relationships between the ELN count and the positive lymph node (PLN) count, the ELN count and the NLN count, and the NLN count and the PLN count.

RESULTS

Survival analyses revealed that the NLN count was significantly associated with OS (P = 0.001) and was an independent predictor (P < 0.01) of prognosis in stage III GC patients. Subgroup analysis showed that the prognostic evaluation accuracy was highest when the NLN count was ≥10 for stage III patients. Stage migrations were mainly detected in the following pathological tumor-node (pTN) subgroups: pT2N3a with 1-9 NLNs and pT2N3b with ≥10 NLNs, and pT3N3a with 1-9 NLNs and pT3N3b with ≥10 NLNs. NLN count was positively correlated with the ELN and the PLN counts for pT2N3 and pT3N3 stage GC patients (r = 0.694 and r = 0.881 for pT2N3 patients; r = 0.685 and r = 0.902 for pT3N3 patients, respectively; P < 0.001). These findings indicate that the NLN count may be a useful prognostic predictor in stage III GC patients.

CONCLUSIONS

The NLN count may improve the prognostic prediction efficiency of the tumor-node-metastasis (TNM) classification for GC, especially for stage III patients, and should be recommended for clinical applications.

Comparing prognostic values of the 7th and 8th editions of the American Joint Committee on Cancer TNM staging system for gastric cancer

Background and Aim:

Our aim was to compare the prognostic value of the American Joint Committee on Cancer (AJCC) 7th and 8th editions staging systems for patients with gastric cancer in China.

Methods:

A total of 1326 gastric cancer patients diagnosed between 2008 and 2012 were included. The discriminative ability of the AJCC 8th and 7th editions was compared using the Harrell’s concordance index (C-index).

Results:

There are two main modifications in the 8th edition. (i) pN3 staging was divided into pN3a and pN3b. The gastric cancer patients with pN3a experienced significantly better overall survival compared with those with pN3b (5-year overall survival: 34.5% vs. 15.6%, P < 0.001) (stratified by pT: pT3: 5-year overall survival: 33.9% vs. 13.2%, P < 0.001; pT4a: 32.8% vs. 16.9%, P = 0.056; pT4b: 17.0% vs. 11.1%, P = 0.048). (ii) Subgroup staging adjustments. The subgroup staging adjustments (T3N3bM0 (IIIB→IIIC), T4aN3aM0 (IIIC→IIIB), T4bN0M0 (IIIB→IIIA), and T4bN2M0 (IIIC→IIIB)) resulted in more gastric cancer patients being accurately staged. Furthermore, the C-index value of the 8th edition tumor node metastasis (TNM) staging system was significantly higher than that of the AJCC 7th TNM staging system to predict the survival of gastric cancer patients (0.701 vs. 0.685, P < 0.001).

Conclusions:

The 8th edition of the TNM staging system is superior to the 7th edition staging system for prediction of survival of gastric cancer patients in China.

Effect of lymph nodes count in node-positive gastric cancer

Background: The retrieved lymph node (LN) count has been confirmed as a prognostic indicator in various cancers. However, the correlation between LN counts and patient prognosis in gastric cancer with node-positive is not fully studied.

Methods: A total of 8475 patients undergoing gastrectomy in Surveillance, Epidemiology, and End Results Program (SEER)-registered gastric cancer were analyzed. Kaplan-Meier methods and multivariable Cox regression models were used to analyze long-term outcomes and risk factors. Moreover, nomograms including LN counts were established to predict overall survival (OS) and cancer-specific survival (CSS), and Harrell's concordance index (c-index) was adopted to evaluate prediction accuracy.

Results: Patients were stratified into 1-6, 7-14, and > 14 subgroups according to the optimal cutoff for retrieved LNs in terms of 5-year CSS. Further analysis indicated that higher LN counts were an independent predictor of longer survival in each N category. Nomograms on CSS and OS were established according to all significant factors, and c-indexes were 0.663 and 0.654 (P< 0.001), respectively.

Conclusions: These results indicated that the more the LNs retrieved, the better the survival would be. Nomograms incorporating LN counts can be recommended as practical models to provide more accurate prognostic information for GC patients.

Evaluation of the Eighth Edition of the American Joint Committee on Cancer TNM Staging System for Gastric Cancer: An Analysis of 7371 Patients in the SEER Database

OBJECTIVE

To investigate the validity of the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging system for gastric cancer.

METHODS

The clinicopathologic data of 7371 patients who were diagnosed with gastric cancer and had 16 or more involved lymph nodes (LNs) were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database and retrospectively reviewed.

RESULTS

Stage migration occurred primarily during stage III between the 7th and 8th edition TNM staging systems. Stages IIIB and IIIC in the 7th edition staging system were divided in the 8th edition and had obvious differences in survival rates (both P < 0.001). The 8th edition TNM stages IIIC and IV showed similar survival rates (P = 0.101). The prognosis of patients with T4aN3bM0 was not different from that of patients with TxNxM1 (P = 0.433), while the prognosis of patients with T4bN3bM0 was significantly poorer than that of patients with TxNxM1 (P = 0.008). A revised TNM system with both T4aN3bM0 and T4bN3bM0 incorporated into stage IV was proposed. Multivariable regression analysis showed that the revised TNM system, but not the 7th and 8th editions, was an independent factor for disease-specific survival (DSS) in the third step of the analysis. Further analyses revealed that the revised TNM system had superior discriminatory ability to the 8th edition staging system, which was also an improvement over the 7th edition staging system.

CONCLUSION

The 8th edition of the AJCC TNM staging system is superior to the 7th edition for predicting the DSS rates of gastric cancer patients. However, for better prognostic stratification, it might be more suitable for T4aN3bM0/T4bN3bM0 to be incorporated into stage IV in the 8th edition TNM staging system.

An Intelligent Clinical Decision Support System for Preoperative Prediction of Lymph Node Metastasis in Gastric Cancer

PURPOSE

The aim of this study was to develop and validate a computational clinical decision support system (DSS) on the basis of CT radiomics features for the prediction of lymph node (LN) metastasis in gastric cancer (GC) using machine learning-based analysis.

METHODS

Clinicopathologic and CT imaging data were retrospectively collected from 490 patients who were diagnosed with GC between January 2002 and December 2016. Radiomics features were extracted from venous-phase CT images. Relevant features were selected, ranked, and modeled using a support vector machine classifier in 326 training and validation data sets. A model test was performed independently in a test set (n = 164). Finally, a head-to-head comparison of the diagnostic performance of the DSS and that of the conventional staging criterion was performed.

RESULTS

Two hundred ninety-seven of the 490 patients examined had histopathologic evidence of LN metastasis, yielding a 60.6% metastatic rate. The area under the curve for predicting LN+ was 0.824 (95% confidence interval, 0.804-0.847) for the DSS in the training and validation data and 0.764 (95% confidence interval, 0.699-0.833) in the test data. The calibration plots showed good concordance between the predicted and observed probability of LN+ using the DSS approach. The DSS was better able to predict LN metastasis than the conventional staging criterion in the training and validation data (accuracy 76.4% versus 63.5%) and in the test data (accuracy 71.3% versus 63.2%) CONCLUSIONS: A DSS based on 13 "worrisome" radiomics features appears to be a promising tool for the preoperative prediction of LN status in patients with GC.

Survival comparison in gastric cancer patients between 7th and 8th edition of the AJCC TNM staging system: The first western single center experience

BACKGROUND

The objective of this study was to compare the 7th and the 8th edition of American Joint Committee on Cancer staging system (AJCC TNM) in terms of better stratification in our gastric cancer resected patients.

METHODS AND MATERIALS

A retrospective analysis of a single western center series was made. Patients who underwent surgery from January 2004 to December 2016 were enrolled in the study. We compared survival rates across patients classified according to the 7th and the 8th AJCC TNM staging system.

RESULTS

Among 295 patients we observed 9.8% stage migration according the 8th edition. Of these 2.1% and 7.9% of patients showed respectively a higher and a lower stage. 5 years Overall Survival (5Y-OS) according to the 8th edition for stage IIIB and IIIC were 32% versus 9% showing a better stratification compared to the 7th edition in which 5Y-OS were respectively 26% versus 22%.

CONCLUSION

Restaging system seems to improve survival rate discrimination in particular comparing stage IIIB and stage IIIC; whereas in stage IIIA this is not so clear. More studies are necessary to confirm these data.

Definition of Prognosis Based on Lymph Node Metastasis and Elevation of Serum C-Reactive Protein for Patients with Gastric Carcinoma Treated with Curative Resection

PURPOSE

The aim of this study was to develop prognostic criteria based on the combination of nodal metastasis and preoperative elevation of serum C-reactive protein (CRP) for patients with gastric carcinoma that have been treated with curative resection.

METHODS

Three hundred and twenty patients with gastric carcinoma who had been treated with curative resection were enrolled. One point was provided for each incidence of nodal metastasis and preoperative elevation of serum CRP and we examined whether this cumulative score system could provide a strict stratification of survival.

RESULTS

Significant differences regarding survival were observed both between patients with scores of 0 and 1 (P < 0.0001) and between patients with scores of 1 and 2 (P < 0.0001). Multivariate analysis showed that the cumulative score (P = 0.0003) and the depth of the tumor (P = 0.016) were independent prognostic indicators.

CONCLUSIONS

Criteria for the prediction of prognosis in gastric carcinoma treated with curative resection based on tumor-related and host-related factors could provide a strict stratification. J. Med. Invest. 65:191-194, August, 2018.

Superiority of the 8th edition of the TNM staging system for predicting overall survival in gastric cancer: Comparative analysis of the 7th and 8th editions in a monoinstitutional cohort

The present study was performed to evaluate the predictive capacity of the 8th edition vs. the 7th edition of the American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) staging system for overall survival (OS) of patients with gastric cancer. Data of eligible patients with gastric cancer in our institution between June 2004 and June 2014 were retrospectively reviewed. A total of 1,506 patients were followed up to July 2016, among whom 1,484 patients with complete stage information were included in the TNM staging analysis. A total of 339 (22.8%) patients presented stage migration, including 325 (21.9%) migrating to a lower tier and 14 (0.9%) to a higher tier. All patients with stage migration to a lower tier were in stage III, including 177 (54.5%) patients migrating from stage IIIB to IIIA, and 148 (45.5%) from stage IIIC to IIIB. Patients migrating from IIIB to IIIA yielded a median OS time and 5-year OS rate closer to those remaining in stage IIIA. Similarly, patients migrating from IIIC to IIIB yielded a median OS time and 5-year OS rate closer to those remaining in stage IIIB. The 7th edition of the staging system exhibited prognostic discrepancy in discriminating stage IIIA from IIIB on survival curves, which was improved in the 8th edition. The 8th edition had a better predictive capability of survival, as evidenced by a smaller value of -2log likelihood in the Cox proportional regression model (7th edition 4738.859 vs. 8th edition 4736.683). Therefore, the present study demonstrated that the 8th edition of the AJCC TNM staging system is superior to the 7th edition in predicting the OS of patients with gastric cancer.

Inhibition of the miR-192/215-Rab11-FIP2 axis suppresses human gastric cancer progression

Less than a century ago, gastric cancer (GC) was the most common cancer throughout the world. Despite advances in surgical, chemotherapeutic, and radiotherapeutic treatment, GC remains the number 3 cancer killer worldwide. This fact highlights the need for better diagnostic biomarkers and more effective therapeutic targets. RAB11-FIP2, a member of the Rab11 family of interacting proteins, exhibits potential tumor suppressor function. However, involvement of RAB11-FIP2 in gastric carcinogenesis is yet to be elucidated. In this study, we demonstrated that RAB11-FIP2 was downregulated in GC tissues and constituted a target of the known onco-miRs, miR-192/215. We also showed that functionally, Rab11-FIP2 regulation by miR-192/215 is involved in GC-related biological activities. Finally, RAB11-FIP2 inhibition by miR-192/215 affected the establishment of cell polarity and tight junction formation in GC cells. In summary, this miR-192/215–Rab11-FIP2 axis appears to represent a new molecular mechanism underlying GC progression, while supplying a promising avenue of further research into diagnosis and therapy of GC.

Increased number of negative lymph nodes is associated with improved survival outcome in node positive gastric cancer following radical gastrectomy

The concept of negative lymph node (NLN) counts has recently attracted attention as a prognostic indicator in various cancer. However, the correlation between NLN counts and patient prognosis in the setting of gastric cancer is not fully studied. Surveillance, Epidemiology, and End Results Program (SEER)-registered gastric cancer patients were used for analysis in this study. Clinicopathological characteristics, including race, age, gender, and tumor stage, grade, and cause specific survival were collected. Univariate and multivariate Cox proportional hazards model were used to assess the risk factors for survival. As results, X-tile plots identified 3 and 9 as the optimal cutoff value to divide the patients into high, middle and low risk subsets in terms of cause specific survival, and NLN was validated as independently prognostic factor in mulivariate Cox analysis (P < 0.001). Further analysis showed that NLN was a prognosis factor in each N stage. Collectively, our study results firmly demonstrated that the number of NLNs was an independent prognostic factor for gastric cancer patients, and together with the N stage, it could provide more accurate prognostic information than the N stage alone.

Western Validation of a Novel Gastric Cancer Prognosis Prediction Model in US Gastric Cancer Patients

BACKGROUND

A novel prediction model for accurate determination of 5-year overall survival of gastric cancer patients was developed by an international collaborative group (G6+). This prediction model was created using a single institution's database of 11,851 Korean patients and included readily available and clinically relevant factors. Already validated using external East Asian cohorts, its applicability in the American population was yet to be determined.

STUDY DESIGN

Using the Surveillance, Epidemiology, and End Results (SEER) dataset, 2014 release, all patients diagnosed with gastric adenocarcinoma who underwent surgical resection between 2002 and 2012, were selected. Characteristics for analysis included: age, sex, depth of tumor invasion, number of positive lymph nodes, total lymph nodes retrieved, presence of distant metastasis, extent of resection, and histology. Concordance index (C-statistic) was assessed using the novel prediction model and compared with the prognostic index, the seventh edition of the TNM staging system.

RESULTS

Of the 26,019 gastric cancer patients identified from the SEER database, 15,483 had complete datasets. Validation of the novel prediction tool revealed a C-statistic of 0.762 (95% CI 0.754 to 0.769) compared with the seventh TNM staging model, C-statistic 0.683 (95% CI 0.677 to 0.689), (p < 0.001).

CONCLUSIONS

Our study validates a novel prediction model for gastric cancer in the American patient population. Its superior prediction of the 5-year survival of gastric cancer patients in a large Western cohort strongly supports its global applicability. Importantly, this model allows for accurate prognosis for an increasing number of gastric cancer patients worldwide, including those who received inadequate lymphadenectomy or underwent a noncurative resection.

Differential expression of two genes Oct-4 and MUC5AC associates with poor outcome in patients with gastric cancer

Gastric cancer (GC) is the most frequent leading cause of cancer-associated mortality worldwide that is linked to poor prognosis due to the lack of appropriate biomarkers. Our aim was to evaluate the MUC5AC and Oct-4 expression levels in GC and to assess their association with clinical factors. Immunohistochemical analysis (IHC) and qRT-PCR were performed in GC patients to examine the MUC5AC and Oct-4 expression levels. The mRNA level of MUC5AC was significantly decreased in tumour tissues compared with non-cancerous tissues (1.11 ± 0.69 vs 3.7 ± 0.71; P = .024). On the other hand, Oct-4 mRNA level was upregulated in tumour tissues as compared to normal tissues (2. 86 ± 0.78 vs 0.87 ± 0.54; P = .0015). Decreased expression of MUC5AC was detected in 27 patients (67.5%), while high to moderate expression levels were observed in 13 cases (32.5%), but in normal tissues the expression levels of MUC5AC were increased (P = .001). The decreased expression of MUC5AC was associated with aggressive tumour characteristics, such as TNM stage (P = .023), histologic type (P = .012) and lymph node metastasis (P = .001). High expression of Oct-4 was detected in 24 tumour tissues (60%), while 16 cases (40%) showed low expression level. Increased Oct-4 expression was correlated with clinicopathological characteristics such TNM stage (P = .002), histologic type (P = .008) and lymph node metastasis (P = .001). Our results showed that high Oct-4 expression and the reduction of MUC5AC expression may be involved in the progression and an unfavorable prognosis of GC.

A Novel Prediction Model of Prognosis After Gastrectomy for Gastric Carcinoma: Development and Validation Using Asian Databases

OBJECTIVE

The prognoses of gastric cancer patients vary greatly among countries. Meanwhile, tumor-node-metastasis (TNM) staging system shows limited accuracy in predicting patient-specific survival for gastric cancer. The objective of this study was to create a simple, yet universally applicable survival prediction model for surgically treated gastric cancer patients.

SUMMARY BACKGROUND DATA

A prediction model of 5-year overall survival for surgically treated gastric cancer patients regardless of curability was developed using a test data set of 11,851 consecutive patients.

METHODS

The model's coefficients were selected based on univariate and multivariate analysis of patient, tumor, and surgical factors shown to significantly impact survival using a Cox proportional hazards model. For internal validation, discrimination was calculated with the concordance index (C-statistic) using the bootstrap method and calibration assessed. The model was externally validated using 4 data sets from 3 countries.

RESULTS

Our model's C-statistic (0.824) showed better discrimination power than current tumor-node-metastasis staging (0.788) (P < 0.0001). Bootstrap internal validation demonstrated that coefficients remained largely unchanged between iterations, with an average C-statistic of 0.822. The model calibration was accurate in predicting 5-year survival. In the external validation, C-statistics showed good discrimination (range: 0.798-0.868) in patient data sets from 4 participating institutions in 3 different countries.

CONCLUSIONS

Utilizing clinically practical patient, tumor, and surgical information, we developed a universally applicable prediction model for accurately determining the 5-year overall survival of gastric cancer patients after gastrectomy. Our predictive model was also valid in patients who underwent noncurative resection or inadequate lymphadenectomy.

Comparison of the 7th and 8th editions of the American joint committee on cancer TNM classification for patients with stage III gastric cancer

Background and Objectives

The eighth TNM edition for gastric cancer was released in 2016 and included major revisions, especially of stage III. The purpose of this study was to evaluate the prognostic value of the new AJCC TNM classification in comparison with the 7th edition for stage III gastric cancer.

Methods

Clinical and histopathological data on 1,496 patients operated on for stage III GC according to the seventh edition between 2005 and 2013 were analyzed and compared using 7th and 8th classifications. The 2 systems were compared in terms of prognostic performance.

Results

The stage shifted for 650 (43.45%) patients: from IIIA to IIIB (2 patient, 0.13%), from IIIB to IIIA (214 patients, 14.30%), from IIIB to IIIC (99 patients, 6.62%), and from IIIC to IIIB (335 patients, 22.39%). Cox regression multivariate analysis showed both the 8th and 7th TNM classification were independent prognostic factors. The 8th edition system had higher linear trend and likelihood ratio χ² scores, and smaller AIC values compared with those for the 7th edition. However, the performance of the eighth edition did not reveal significant improvement compared to the seventh edition (c-index 0.625 vs. c-index 0.616, p=0.085).

Conclusion

The eighth TNM edition may not provide significantly better accuracy in predicting the prognosis of stage III GC. However, to confirm our findings, further studies are warranted.

Harvest of at Least 23 Lymph Nodes is Indispensable for Stage N3 Gastric Cancer Patients

BACKGROUND

The National Comprehensive Cancer Network (NCCN) recommends that at least 15 lymph nodes (LNs) be removed during radical gastrectomy. This study aims to investigate the optimal number of LNs resected for radical gastrectomy.

PATIENTS AND METHODS

From September 2008 to March 2015, a total of 1990 gastric cancer patients were enrolled in this study. Clinicopathological features and survivals were recorded, and the association between the number of LNs resected and the prognosis of gastric cancer were analyzed.

RESULTS

Overall, 1520 males (76.4%) and 470 females (23.6%) were included in the study, with a median age of 57 years (range 20-90). The median number of LNs resected was 24 (range 15-83) for stage N1, 25 (range 15-62) for stage N2, 25 (range 15-88) for stage N3a, and 28 (range 16-73) for stage N3b. The optimal cut-off value for the number of LNs resected was 22 for stage N3a (p = 0.000) and N3b (p = 0.003) patients, while no other cut-off value was significantly superior to 15 for stage N1-2 patients (both p > 0.05). Age, tumor size, tumor depth, and number of LNs resected were independent prognostic predictors for stage N3a patients, while resection type and number of LNs resected were independent prognostic predictors for stage N3b patients. Removing more than 22 LNs exhibited a significant survival benefit compared with removing 15-22 LNs for stage N3a and N3b patients (29.7 vs. 21.6%, p = 0.000; 12.9% vs. 0%, p = 0.003, respectively).

CONCLUSION

Removing at least 23 LNs could yield better survival outcomes in stage N3 gastric cancer patients.

Oct-4 is associated with gastric cancer progression and prognosis

Aim

To investigate the clinical significance of Oct-4 in the development and progression of gastric cancer.

Methods

Immunohistochemistry was used to analyze Oct-4 expression in 412 gastric cancer cases. Oct-4 protein levels were upregulated in gastric cancer tissues compared with adjacent noncancerous tissues.

Results

Positive expression of Oct-4 correlated with age, depth of invasion, Lauren classification, lymph node metastasis, distant metastasis, and TNM stage. In stages I, II, and III, the 5-year survival rate of patients with high expression of Oct-4 was significantly lower than that in patients with low expression of Oct-4. In stage IV, Oct-4 expression did not correlate with the 5-year survival rate. Furthermore, multivariate analysis suggested that the depth of invasion, lymph node metastasis, distant metastasis, TNM stage, and upregulation of Oct-4 were independent prognostic factors of gastric cancer.

Conclusion

Oct-4 protein is a useful marker in predicting tumor progression and prognosis.

Prognostic Significance of Tumor Size in 2405 Patients With Gastric Cancer: A Retrospective Cohort Study

The clinical prognostic significance of tumor size (Ts) in gastric cancer remains under debate. This study aims to evaluate the prognostic value of Ts in gastric cancer patients undergoing gastrectomy. A total of 2405 patients with gastric cancer, all having received radical resection, were enrolled in this retrospective study from 2000 to 2011. Patients were categorized by minimum P value from log-rank χ2 statistics using X-tile. The relationships between Ts and other clinicopathologic characteristics were analyzed, and the survival prediction accuracy was also compared between Ts and T stage. Patients were divided into 5 groups, according to which Ts stage and TsNM stage system were proposed. Ts, an independent prognostic factor identified by univariate and multivariate survival analysis, was significantly associated with sex, age, tumor location, macroscopic type, tumor diffferentiation, vessel invasion, perineural invasion, T stage, N stage, and TNM stage. Compared with T stage system, Ts stage system was found no superiorities in survival prediction. However, for patients with lymph node metastasis and patients with age ≥60, Ts stage system revealed a significant improvement of predictive accuracy in subgroup survival analysis. Furthermore, TsNM stage (c-index = 0.783) system was found to be superior to TNM stage (c-index = 0.743) system in prognostic prediction accuracy (P < 0.05). Ts is significantly correlated with gastric cancer progression, which can be regarded as a reliable prognostic factor, and the TsNM stage system may improve the prognostic prediction accuracy in gastric cancer patients.

Prognostic significance of metastatic lymph node number, ratio and station in gastric neuroendocrine carcinoma

The objective of this study was to analyze the prognostic significance of metastatic lymph node status in gastric neuroendocrine carcinoma (GNEC) patients following radical gastrectomy. A consecutive series of 73 patients who underwent gastrectomy between 1999 and 2011 for GNEC was retrospectively reviewed. Indexes of lymph node involvement (the pN classification, metastatic lymph node number [MLNn], ratio [MLNr], and station [MLNs]) and other clinicopathological data were analyzed. Fifty-four patients met the inclusion criteria and were enrolled in the study. Among them, 44 patients (81 %) were found to have lymph node metastases. The median survival time of the entire cohort was 63.2 (range, 14-153) months with 3- and 5-year survival rates of 88.9 and 47.9 %, respectively. The median total number of lymph nodes, MLNn, and MLNr were 19 (range, 10-56), 5 (range, 1-21), and 25 % (6-100 %), respectively. Cox regression analysis revealed pN classification = 1, MLNn >2, MLNr >0.1, and MLNs = 2, and distant metastases influenced prognosis independently (P = 0.0266, 0.0091, 0.0031, 0.0119, and 0.0021, respectively). In addition to the pN classification, indexes of metastatic lymph node involvement, including MLNn, MLNr, and MLNs, were all significant predictors of survival in GNEC patients. Distant metastasis was also a significant prognostic factor. These indexes proved to be accurate and important supplements to survival factors, which may improve risk classification of GNEC patients.

Microenvironment of tumor-draining lymph nodes: opportunities for liposome-based targeted therapy

The World Health Organization (WHO) recently reported that the total number of global cancer cases in 2013 reached 14 million, a 10% rise since 2008, while the total number of cancer deaths reached 8.2 million, a 5.2% increase since 2008. Metastasis is the major cause of death from cancer, accounting for 90% of all cancer related deaths. Tumor-draining lymph nodes (TDLN), the sentinel nodes, are the first organs of metastasis in several types of cancers. The extent of metastasis in the TDLN is often used in disease staging and prognosis evaluation in cancer patients. Here, we describe the microenvironment of the TDLN and review the recent literature on liposome-based therapies directed to immune cells within the TDLN with the intent to target cancer cells.

Three-step method for systematic lymphadenectomy in gastric cancer surgery using the 'curettage and aspiration dissection technique' with Peng's multifunctional operative dissector

BACKGROUND

Gastric cancer is one of the most common malignancies and is a leading cause of cancer death worldwide. Surgery is the most effective and successful method of treatment for gastric cancer, and systematic lymph node (LN) dissection is unquestionably the most effective procedure for treating LN metastases of gastric cancer. Systematic lymphadenectomy is the most important part of curative resection, but lymphadenectomy is also the most difficult procedure in gastric cancer surgery. The aim of this study is to report our three-step method for lymphadenectomy in gastric cancer.

METHODS

In this study, the lymph node stations and groups were defined according to the 13th edition of the Japanese Classification for Gastric Carcinoma. The authors' novel, simplified method consists of three steps: (1) the Kocher maneuver and dissection of the greater omentum together with the anterior sheet of the mesocolon, (2) dissection of the lesser omentum, and (3) lymphadenectomy following the main vessels. We primarily used Peng's multifunctional operative dissector, which combines four different functions (cutting, separating, aspirating and coagulating). Our systematic lymphadenectomy included three steps, and the main procedure started from right to left and in the caudal to cranial direction.

RESULTS

A total of 830 consecutive patients underwent our three-step-method systematic lymphadenectomy in advanced gastric cancer surgery. The mean operation time was 146 minutes, and the mean blood loss was 248 ml. The median postoperative hospital stay was 10.9±4.8 days. The median number of examined LN was 31.6 (range 17 to 72) per patient, and the median number of metastatic LN was 5.6 (range 0 to 42) per patient. The overall incidence of postoperative complications was 10.6%, and the rate of hospital death was 0.9%. The overall three-year survival rate was 52.6%.

CONCLUSIONS

Our three-step method for lymphadenectomy is easy to perform and is a useful procedure for gastric cancer surgery.

Is tumor size a predictor of preoperative N staging in T2-T4a stage advanced gastric cancer?

BACKGROUND

The aim of this study was to assess the relationship between tumor size and preoperative N staging in patients with T2-T4a stage advanced gastric cancer.

METHODS

A total of 697 patients with gastric cancer were analyzed. The correlations between the number of metastatic lymph nodes (LNs) and other clinicopathologic factors were investigated. The Kappa consistency test was used to test the agreement between predicted and pathologic N staging.

RESULTS

Multivariate analysis showed that tumor size was independently (r = 0.987, P < 0.05) and linearly (R(2) = 0.940, P < 0.05) correlated with the number of metastatic LNs. The numbers of predicted metastatic LNs in patients with primary tumors <2.02 cm, 2.02-4.07 cm, 4.07-6.80 cm, and ≥ 6.80 cm in size were 0 (Stage N0), 1-2 (Stage N1), 3-6 (Stage N2), and ≥ 7 (Stage N3), respectively. There was good agreement between N staging predicted by tumor size and pathologic N staging (Kappa value = 0.531, P < 0.05). The overall accuracy of tumor size for preoperative N staging was 82.13%. The 5-year survival rates of patients with predicted Stages N0, N1, N2, and N3 were 80.0%, 71.1%, 56.8%, and 39.8%, respectively (P < 0.05). There were no significant differences in the survival rates of patients with predicted N staging and the corresponding pathologic N staging.

CONCLUSIONS

Tumor size is correlated with the number of LN metastases in patients with stage T2-T4a advanced gastric cancer. The measurements of tumor size can predict preoperative N staging.

Validity and necessity of sub-classification of N3 in the 7th UICC TNM stage of gastric cancer

BACKGROUND

The 7th TNM staging is the first authoritative standard for evaluation of effectiveness of treatment of gastric cancer worldwide. However, revision of pN classification within TNM needs to be discussed. In particular, the N3 sub-stage is becoming more conspicuous.

METHODS

Clinical data of 302 pN3M0 stage gastric cancer patients who received radical gastrectomy in Tianjin Medical University Cancer Institute and Hospital from January 2001 to May 2006 were retrospectively analyzed.

RESULTS

Location of tumor, depth of invasion, extranodal metastasis, gastric resection, combined organs resection, lymph node metastasis, rate of lymph node metastasis, negative lymph nodes count were important prognostic factors of pN3M0 stage gastric cancers. TNM stage was also associated with prognosis. Patients at T2N3M0 stage had a better prognosis than other sub-classification. T3N3M0 and T4aN3aM0 patients had equal prognosis which followed the T2N3M0. T4aN3bM0 and T4bN3aM0 had lower survival rate than the formers. T4bN3bM0 had worst prognosis. In multivariate analysis, TNM stage group and rate of lymph node metastasis were independent prognostic factors.

CONCLUSIONS

The sub-stage of N3 may be useful for more accurate prediction of prognosis; it should therefore be applied in the TNM stage system.

Role of salvage radiotherapy for regional lymph node recurrence after radical surgery in advanced gastric cancer

PURPOSE

To evaluate the role of salvage radiotherapy (RT) for the treatment of regional lymph node recurrence (RLNR) after radical surgery in advanced gastric cancer.

MATERIALS AND METHODS

We retrospectively analyzed medical records of 26 patients who underwent salvage treatment after diagnosis of RLNR between 2006 and 2011. Patients with peritoneal seeding or distant metastasis were excluded. Eighteen patients received RT with or without chemotherapy and the other 8 did chemotherapy only without RT. A three-dimensional conformal RT was performed with median dose of 56 Gy (range, 44 to 60 Gy). Sixteen patients had fluoropyrimidine-based chemotherapy, 5 did taxane-based chemotherapy, and irinotecan was applied in 4.

RESULTS

With a median follow-up of 20 months (range, 5 to 57 months), median overall survival (OS) and progression-free survival (PFS) after diagnosis of RLNR were 29 months and 12 months in the entire patients, respectively. Radiotherapy (p = 0.007) and disease-free interval (p = 0.033) were statistically significant factors for OS in multivariate analysis. Median OS was 36 months in patients who received RT and 16 months in those who did not. Furthermore, delivery of RT (p < 0.001), complete remission after salvage treatment (p = 0.040) and performance status (p = 0.023) were associated with a significantly better PFS. Gastrointestinal toxicities from RT were mild in most patients.

CONCLUSION

Salvage RT combined with systemic chemotherapy may be an effective treatment managing RLNR from advanced gastric cancer.

L1 and epithelial cell adhesion molecules associated with gastric cancer progression and prognosis in examination of specimens from 601 patients

Background

L1 cell adhesion molecule (L1CAM) and epithelial cell adhesion molecule (EPCAM) have been implicated in the development and progression of gastric cancer. The present study investigated the clinical significance of L1CAM and EPCAM in the development, progression and prognosis of gastric cancer.

Methods

Expression of L1CAM and EPCAM were examined immunochemically in 601 clinicopathologically characterized gastric cancer cases.

Results

L1CAM protein was detected in 23.9% of human non-tumor mucosa samples. All samples expressed L1CAM protein at low levels. High expression of L1CAM protein was detected in 163 (27.1%) tumors. Expression of L1CAM correlated with age, tumor location, size of tumors, Lauren’s classification, depth of invasion, lymph node and distant metastases, regional lymph node stage, Tumor-Node-Metastasis (TNM) stage and prognosis. EPCAM protein was detected in 45.7% of human non-tumor mucosa samples. All samples expressed EPCAM protein at low levels. High expression of EPCAM protein was detected in 247 (41.1%) tumors. Expression of EPCAM correlated with age, tumor location, size of tumors, Lauren’s classification, depth of invasion, lymph node and distant metastases, regional lymph node stage, TNM stage and prognosis. Cumulative 5-year survival rates of patients with high expression of both L1CAM and EPCAM were significantly lower than in patients with low expression of both.

Conclusions

Expression of L1CAM and EPCAM in gastric cancer was significantly associated with lymph node and distant metastasis, and poor prognosis. L1CAM and EPCAM proteins could be useful markers to predict tumor progression and prognosis.

Effects of extended lymphadenectomy and postoperative chemotherapy on node-negative gastric cancer

AIM: To investigate the effects of extended lymphadenectomy and postoperative chemotherapy on gastric cancer without lymph node metastasis.

METHODS: Clinical data of 311 node-negative gastric cancer patients who underwent potentially curative gastrectomy with more than 15 lymph nodes resected, from January 2002 to December 2006, were analyzed retrospectively. Patients with pT4 stage or distant metastasis were excluded. We analyzed the relationship between the D2 lymphadenectomy and the 5-year survival rate among different subgroups stratified by clinical features, such as age, tumor size, tumor location and depth of invasion. At the same time, the relationship between postoperative chemotherapy and the 5-year survival rate among different subgroups were also analyzed.

RESULTS: The overall 5-year survival rate of the entire cohort was 63.7%. The 5-year survival rate was poor in those patients who were: (1) more than 65 years old; (2) with tumor size larger than 4 cm; (3) with tumor located in the upper portion of the stomach; and (4) with pT3 tumor. The survival rate was improved significantly by extended lymphadenectomy only in patients with pT3 tumor (P = 0.019), but not in other subgroups. Moreover, there was no significant difference in survival rate between patients with and without postoperative chemotherapy among all of the subgroups (P > 0.05).

CONCLUSION: For gastric cancer patients without lymph node metastasis, extended lymphadenectomy could improve the survival rate of those who have pT3-stage tumor. However, there was no evidence of a survival benefit from postoperative chemotherapy alone.

Tumor size as a prognostic factor in patients with advanced gastric cancer in the lower third of the stomach

AIM: To explore the impact of tumor size on outcomes in patients with advanced gastric cancer in the lower third of the stomach.

METHODS: We retrospectively analyzed the clinical records of 430 patients with advanced gastric cancer in the lower third of the stomach who underwent distal subtotal gastrectomy and D2 lymphadenectomy in our hospital from January 1998 to June 2004. Receiver-operating characteristic (ROC) curve analysis was used to determine the appropriate cutoff value for tumor size, which was measured as maximum tumor diameter. Based on this cutoff value, patients were divided into two groups: those with large-sized tumors (LSTs) and those with small-sized tumors (SSTs). The correlations between other clinicopathologic factors and tumor size were investigated, and the 5-year overall survival (OS) rate was compared between the two groups. Potential prognostic factors were evaluated by univariate Kaplan-Meier survival analysis and multivariate Cox’s proportional hazard model analysis. The 5-year OS rates in the two groups were compared according to pT stage and pN stage.

RESULTS: The 5-year OS rate in the 430 patients with advanced gastric cancer in the lower third of the stomach was 53.7%. The mean ± SD tumor size was 4.9 ± 1.9 cm, and the median tumor size was 5.0 cm. ROC analysis indicated that the sensitivity and specificity results for the appropriate tumor size cutoff value of 4.8 cm were 80.0% and 68.2%, respectively (AUC = 0.795, 95%CI: 0.751-0.839, P = 0.000). Using this cutoff value, 222 patients (51.6%) had LSTs (tumor size ≥ 4.8 cm) and 208 (48.4%) had SSTs (tumor size < 4.8 cm). Tumor size was significantly correlated with histological type (P = 0.039), Borrmann type (P = 0.000), depth of tumor invasion (P = 0.000), lymph node metastasis (P = 0.000), tumor-nodes metastasis stage (P = 0.000), mean number of metastatic lymph nodes (P = 0.000) and metastatic lymph node ratio (P = 0.000). Patients with LSTs had a significantly lower 5-year OS rate than those with SSTs (37.1% vs 63.3%, P = 0.000). Univariate analysis showed that depth of tumor invasion (χ² = 69.581, P = 0.000), lymph node metastasis (χ² = 138.815, P = 0.000), tumor size (χ² = 78.184, P = 0.000) and metastatic lymph node ratio (χ² = 139.034, P = 0.000) were significantly associated with 5-year OS rate. Multivariate analysis revealed that depth of tumor invasion (P = 0.000), lymph node metastasis (P = 0.019) and tumor size (P = 0.000) were independent prognostic factors. Gastric cancers were divided into 12 subgroups: pT2N0; pT2N1; pT2N2; pT2N3; pT3N0; pT3N1; pT3N2; pT3N3; pT4aN0; pT4aN1; pT4aN2; and pT4aN3. In patients with pT2-3N3 stage tumors and patients with pT4a stage tumors, 5-year OS rates were significantly lower for LSTs than for SSTs (P < 0.05 each), but there were no significant differences in the 5-year OS rates in LST and SST patients with pT2-3N0-2 stage tumors (P > 0.05).

CONCLUSION: Using a tumor size cutoff value of 4.8 cm, tumor size is a prognostic factor in patients with pN3 stage or pT4a stage advanced gastric cancer located in the lower third of the stomach.

Detection and clinical significance of lymph node micrometastasis in gastric cardia adenocarcinoma

OBJECTIVES

Lymph node micro metastasis was investigated in gastric cardia adenocarcinoma (GCA) patients without lymph node metastasis on routine pathological examination. The relationship between micrometastasis and clinicopathological features was also evaluated.

METHODS

A total of 349 lymph nodes were obtained from 45 patients with GCA. Micrometastases were detected by immunohistochemical staining for the markers cytokeratin 19 (CK19) and CD44 variant 6 (CD44v6).

RESULTS

A total of 33 lymph nodes (9.5%) from 15 patients (33.3%) were positive for CK19. Of these, 27 lymph nodes (7.7%) from 12 patients (26.7%) were also positive for CD44v6. Micrometastasis was significantly related to depth of tumour invasion and Lauren classification (intestinal or diffuse). The recurrence rate was significantly higher and 2-year survival rate significantly lower in patients with than in those without lymph node micrometastasis, showing the necessity of detecting micrometastasis in GCA patients who test negative for lymph node metastasis on routine examination.

CONCLUSION

CK19 and CD44v6 were shown to be good markers for micrometastasis detection.

Identification of a DNA methylation marker that detects the presence of lymph node metastases of gastric cancers

The accurate detection of the presence of lymph node metastases (LNM) of gastric cancers (GCs) is useful for the implementation of necessary and sufficient treatment, but current methods of detection are unsatisfactory. In the present study, we focused on DNA methylation markers since they have several advantages, including biological and chemical stability and informativeness even in the presence of contaminating cells. Using three metastatic lymph nodes and three primary GCs without LNM, methylation bead array analyses were performed, which enabled the interrogation of 485,577 CpG sites. A total of 31 CpG sites that were hypermethylated in the metastatic lymph nodes, compared with the GCs without LNM, were isolated. Using primary GCs with and without LNM (28 GCs with LNM and 10 without), their methylation levels were measured using quantitative PCR following treatment with sodium bisulfite or a methylation-sensitive restriction enzyme. Of the genomic regions around the 31 CpG sites, 10 regions demonstrated higher methylation levels in the GCs with LNM compared with the GCs without LNM (P<0.05). Finally, the hypermethylation of the 10 regions was validated using another set of samples (129 GCs with LNM and 20 without). Hypermethylation of the region around the cg06436185 CpG site predicted the presence of LNM at a sensitivity of 43% and specificity of 85%. Additionally, the hypermethylation of the region was associated with a poor survival rate among GC patients with LNM. The results of the present study indicated that the methylation status of the region was a promising candidate marker to detect the presence of LNM of GCs and may reflect the malignant potential of GCs.

Correlation between efficacy of PSK postoperative adjuvant immunochemotherapy for gastric cancer and expression of MHC class I

Protein-bound polysaccharide K (PSK) is a glycoprotein that is purified from the mushroom Coriolus versicolor. In Japan, PSK is clinically used in combination with anticancer agents following gastric cancer surgery. Evaluation of the response is difficult, as efficacy is determined via antitumor immunoenhancing effects, and for that reason PSK has not become a standard therapy. The present study evaluated the expression of MHC class I in gastric cancer patients who received PSK postoperative adjuvant immunochemotherapy, and investigated the correlation between MHC class I expression and clinical outcomes. The subjects comprised 349 patients with stage II/III gastric cancer, who had received adjuvant therapy following curative resection between 1995 and 2008. MHC class I expression in the primary lesion was evaluated by immunohistochemical staining. Patients were divided into two treatment groups: one was only administered oral chemotherapy (chemotherapy-only group) and the other was administered chemotherapy plus PSK (PSK group). The clinical outcomes were compared between the two groups. The two groups did not differ in regard to their MHC class I expression. Expression-negative cases demonstrated 3-year recurrence-free survival (RFS) rates of 65% in the PSK group and 47% in the chemotherapy-only group. Therefore, the PSK group revealed a prolonged survival. For the 82 expression-negative cases with pN2 or greater, the RFS rates were 68% in the PSK group and 28% in the chemotherapy-only group, representing a significant difference. Thus, PSK adjuvant immunochemotherapy may be effective in MHC class I-negative patients, who are in a state of antitumor immunological tolerance, and patients with advanced lymph node metastasis of pN2 or greater.

Clinical implication of an insufficient number of examined lymph nodes after curative resection for gastric cancer

BACKGROUND

The seventh edition of the tumor, lymph node (LN), metastasis (TNM) staging system increased the required number of examined LNs in gastric cancer from 15 to 16. However, the same staging system defines lymph node-negative gastric cancer regardless of the number of examined LNs. In this study, the authors evaluated whether gastric cancer can be staged properly with fewer than 15 examined LNs.

METHODS

The survival rates of 10,010 patients who underwent curative gastrectomy from 1987 to 2007 were analyzed. The patients were divided into 2 groups according to the number of examined LNs, termed the "insufficient" group (≤15 examined LNs) and the "sufficient" group (≥16 examined LNs). The survival curves of patients from both groups were compared according to the seventh edition of the TNM classification.

RESULTS

Three hundred sixteen patients (3.2%) had ≤15 examined LNs for staging after they underwent standard, curative lymphadenectomy. Patients who had T1 tumor classification, N0 lymph node status, and stage I disease with an insufficient number of examined LNs after curative gastrectomy had a significantly worse prognosis than patients who had ≥16 examined LNs. Moreover, having an insufficient number of examined LNs was an independent prognostic factor for patients who had T1, N0, and stage I disease.

CONCLUSIONS

Lymph node-negative cancers in which ≤15 LNs were examined, classified as N0 in the new TNM staging system, could not adequately predict patient survival after curative gastrectomy, especially in patients with early stage gastric cancer.

Evaluation of the seventh edition of American Joint Committee on Cancer TNM staging system for gastric cancer: results from a Chinese monoinstitutional study

BACKGROUND

To investigate the validity of the 7th edition of American Joint Committee on Cancer (AJCC) TNM staging system for gastric cancer with special attention paid to pT2/pT3, pN1/pN2, and pN3a/pN3b category.

MATERIALS AND METHODS

Clinicopathologic data of 1998 patients underwent R0 surgery for histologically proven gastric cancers with >15 lymph nodes retrieved were retrospectively reviewed.

RESULTS

Prognoses were significantly different between pT2 and pT3 categories, between pN1 and pN2 categories, or between pN3a and pN3b categories. Each stage in the 6th edition was divided into the 7th edition stage with different survival rates. Moreover, stage IIIA, IIIB, and IIIC in the 7th edition system was divided into the 6th edition stage with different survival rates. Prognoses for patients in 7th edition T4aN1M0/T3N2M0/T2N3aM0, T4bN0-1M0/T4aN2M0/T3N3aM0, and T4aN3aM0/T4bN2M0 were similar to that of patients in T1N3bM0, T2N3bM0, and T3N3bM0, respectively, but significantly better than that of patients in T2N3bM0, T3N3bM0, and T4aN3bM0, respectively. However, no significant difference could be observed among patients in T4bN3aM0, T4aN3bM0, T4bN3bM0, and stage IV. A revised TNM system was proposed, in which T1N3bM0 was incorporated into stage IIIA, T2N3bM0 into stage IIIB, T3N3bM0 into stage IIIC, T4bN3aM0/T4aN3bM0/T4bN3bM0 into stage IV. Further analyses revealed the revised TNM system had better homogeneity, discriminatory ability, and monotonicity of gradients than the 6th and the 7th edition system.

CONCLUSIONS

It is reasonable to subclassify the 6th edition pT2 category and pN1 category into the 7th edition pT2/pT3 category and pN1/pN2 category, respectively. However, for better prognostic stratification, it might be more suitable for pN3a and pN3b categories to be considered individual determinants of the 7th edition TNM staging system.

Assessment of the nodal status in ampullary carcinoma: the number of positive lymph nodes versus the lymph node ratio

BACKGROUND

This study was intended to compare the prognostic power of the number of positive lymph nodes with that of the lymph node ratio in patients with ampullary carcinoma.

METHODS

A retrospective analysis was conducted of the medical records of 71 consecutive patients with ampullary carcinoma who underwent pancreaticoduodenectomy with regional lymph node dissection. A total of 2151 lymph nodes were dissected (median: 28 nodes per patient) and examined histologically. Cutoff points were determined for both the number of positive nodes and the lymph node ratio using χ(2) scores calculated with the Cox proportional hazards regression model.

RESULTS

Lymph node metastasis was found in 34 patients. The best cutoff point for the number of positive nodes was identified as three nodes, and that for the lymph node ratio was identified as 10%. Univariate analysis revealed both the number of positive nodes (0, 1-3, or ≥ 4; P < 0.0001) and the lymph node ratio (0%, 0-10%, or >10%; P < 0.0001) as significant prognostic factors. Multivariate analysis identified the number of positive nodes as an independent prognostic factor (P < 0.001), whereas the lymph node ratio failed to remain as an independent variable. The cumulative 5-year survival rates were 85% for patients with 0 positive nodes, 63% for patients with 1-3 positive nodes, and 0% for patients with ≥ 4 positive nodes (P < 0.0001).

CONCLUSIONS

The number of positive lymph nodes better predicts the outcome after resection than the lymph node ratio in patients with ampullary carcinoma.

Effect of negative lymph node count on survival for gastric cancer after curative distal gastrectomy

AIMS

The aim of this study is to evaluate the long-term effect of negative lymph node (LN) counts on the prognosis after curative distal gastrectomy among gastric cancer patients.

METHODS

The study enrolled 634 patients with gastric cancer, who had undergone curative resection (R0) with distal gastrectomy from 1995 to 2004. Long-term surgical outcomes and relationships between the negative LN count and the 5-year survival rate were investigated.

RESULTS

The 5-year survival rate of the entire cohort was 57.6%. The number of metastasis negative LN was positively associated with the retrieved node according to the Pearson's correlation test (P < 0.001). Cox regression analysis showed the negative LN count was an independent predictor of survival (P < 0.05). Based on the statistical assumption the best fitting linear, linear regression showed a significant survival improvement based on increasing negative LN count for patients with stages I (P = 0.014), II (P = 0.011) and III (P = 0.003). The greatest survival differences were observed at cutoff value 10 negative LN counts for stage I, and 15 for stages II, III and IV.

CONCLUSION

Negative LN counts can reflect the extent of lymphadenectomy for gastric cancer after curative distal gastrectomy. The higher the negative LN count, the better the survival would be; the best long-term survival outcome was observed on the negative LN count more than 10 (stage I) or 15 (stages II, III, and IV).

Validation of the seventh edition of the American Joint Committee on Cancer TNM staging system for gastric cancer

BACKGROUND

The seventh edition of the American Joint Committee on Cancer (AJCC) TNM classification for gastric cancer was published in 2010 and included major revisions. The aim of the current study was to evaluate the validity of the seventh edition TNM classification for gastric cancer based on an Asian population.

METHODS

A total of 2916 gastric cancer patients who underwent R0 surgical resection from 1989 through 2008 in a single institute were included, and were analyzed according to the seventh edition of the TNM classification for validation.

RESULTS

When adjusted using the seventh edition of the TNM classification, upstaging was observed in 771 patients (26.4%) and downstaging was observed in 178 patients (6.1%) compared with the sixth edition of the TNM classification. The relative risk (RR) of seventh edition pT classification was found to be increased with regular intensity compared with the sixth edition pT classification. The RR of seventh edition pN classification was found to be increased with irregular intensity compared with the sixth edition pN classification. In survival analysis, there were significant differences noted for each stage of disease, but only a marginal difference was demonstrated between stage IA and stage IB (P = .049). In the hybrid TNM classification, which combines the seventh edition pT classification and the sixth edition pN classification, both pT and pN classifications demonstrated a more ideal distribution of the RR, and 5-year survival rates also showed a significant difference for each stage (P <.01).

CONCLUSIONS

The seventh edition of the TNM classification was considered valid based on the results of the current study. However, the hybrid TNM classification, comprised of a combination of the seventh edition pT classification and sixth edition pN classification, should be considered for the next edition.

Comparison of four staging systems of lymph node metastasis in gastric cancer

BACKGROUND

The classification of lymph node metastasis in patients with gastric cancer is still controversial. Our aim was to evaluate the relative merits of four staging systems of lymph node metastasis.

METHODS

In our study, the nodal status was classified according to the 5th edition of the tumor node metastasis (TNM) system, the Japanese Classification of Gastric Carcinoma (JCGC), the ratio of metastatic lymph nodes, and the size of the largest metastatic lymph node. Each staging system was scored as good (+2), fair (+1), or poor (0) with respect to the theoretical value (extent of the anatomical lymphatic tumor spread), convenience (simplicity), surgical applicability (extent of lymph node dissection), and prognostic value (ability to predict survival rate).

RESULTS

In the multivariate analysis including the four staging systems and other potential prognostic factors, stepwise Cox regression revealed that the ratio of metastatic lymph nodes was the most independent prognostic factor. The TNM, ratio, and size systems were convenient because they had no consideration for the location of the tumor and lymph node. Although the JCGC system had advantages in theoretical value and surgical application, it was most optional due to the complexity of the system.

CONCLUSIONS

Although all different staging systems are comparable, the metastatic lymph node ratio system is convenient, reproducible, and has the highest ability to predict survival.

Prognostic impact of metastatic lymph node ratio on gastric cancer after curative distal gastrectomy

AIM: To investigate the prognostic impact of metastatic lymph node ratio (rN) on gastric cancer after curative distal gastrectomy.

METHODS: A total of 634 gastric cancer patients who underwent curative resection (R0) of lymph nodes at distal gastrectomy in 1995-2004. Correlations between positive nodes and retrieved nodes, between rN and retrieved nodes, and between rN and negative lymph node (LN) count were analyzed respectively. Prognostic factors were identified by univariate and multivariate analyses. Staging accuracy of the pN category (5th UICC/TNM system) and the rN category was compared according to the survival rates of patients. A linear regression model was used to identify the relation between rN and 5-year survival rate of the patients.

RESULTS: The number of dissected LNs was related with metastatic LNs but not related with rN. Cox regression analysis showed that depth of invasion, pN and rN category were the independent predictors of survival (P < 0.05). There was a significant difference in survival between LN stages classified by the rN category or by the pN category (P < 0.05). However, no significant difference was found in survival rate between LN stages classified by the pN category or by the rN category (P > 0.05). Linear regression model showed a significant linear correlation between rN and the 5-year survival rate of gastric cancer patients (β = 0.862, P < 0.001). Pearson’s correlation test revealed that negative LN count was negatively correlated with rN (P < 0.001).

CONCLUSION: rN category is a better prognostic tool than the 5th UICC pN category for gastric cancer patients after curative distal gastrectomy. Increased negative LN count can reduce rN and improve the survival rate of gastric cancer patients.