Gastric carcinoma: stage migration by immunohistochemically detected lymph node micrometastases

Indocyanine green fluorescence imaging-guided versus conventional laparoscopic lymphadenectomy for gastric cancer: long-term outcomes of a phase 3 randomised clinical trial

Indocyanine green (ICG) fluorescence imaging-guided lymphadenectomy has been demonstrated to be effective in increasing the number of lymph nodes (LNs) retrieved in laparoscopic gastrectomy for gastric cancer (GC). Previously, we reported the primary outcomes and short-term secondary outcomes of a phase 3, open-label, randomized clinical trial (NCT03050879) investigating the use of ICG for image-guided lymphadenectomy in patients with potentially resectable GC. Patients were randomly (1:1 ratio) assigned to either the ICG or non-ICG group. The primary outcome was the number of LNs retrieved and has been reported. Here, we report the primary outcome and long-term secondary outcomes including three-year overall survival (OS), three-year disease-free survival (DFS), and recurrence patterns. The per-protocol analysis set population is used for all analyses (258 patients, ICG [n = 129] vs. non-ICG group [n = 129]). The mean total LNs retrieved in the ICG group significantly exceeds that in the non-ICG group (50.5 ± 15.9 vs 42.0 ± 10.3, P < 0.001). Both OS and DFS in the ICG group are significantly better than that in the non-ICG group (log-rank P = 0.015; log-rank P = 0.012, respectively). There is a difference in the overall recurrence rates between the ICG and non-ICG groups (17.8% vs 31.0%). Compared with conventional lymphadenectomy, ICG guided laparoscopic lymphadenectomy is safe and effective in prolonging survival among patients with resectable GC.

A combined approach for individualized lymphadenectomy in gastric cancer patients

Introduction: Gastric cancer ranks as the fifth most common cancer globally. The presence of lymph node metastasis is a significant prognostic factor influencing survival. Postoperative morbidity and nodal staging accuracy are heavily affected by the extent of lymph node dissection. Our study aimed to explore the potential integration of two contemporary methods, sentinel node navigation surgery (SNNS) and the Maruyama Computer Program (MCP), to improve the accuracy of nodal staging. Materials and methods: We conducted a prospective data collection involving patients with gastric adenocarcinoma from 2008 to 2018 at the Department of Surgery, University of Debrecen, Hungary. Data from 100 consecutive patients were collected. The primary and secondary endpoints included evaluating the rate of node-negative patients and the diagnostic accuracy of our combined approach. Results: Sentinel node mapping was successful in 97 out of 100 patients. We found that using the threshold value of the Maruyama Index (MI) ≥ 28, all metastatic stations of sentinel-node-negative patients could be identified. Our method achieved 100% sensitivity and negative predictive value, with a specificity of 60.42% (95% CI = 46.31%-72.98%). Discussion: The combined application of SNNS and MCP has proven to be an effective diagnostic technique in the synergistic approach for identifying metastasis-positive lymph node stations. Despite its limitations, this combination may assist clinicians in customizing lymphadenectomy for gastric cancer patients.

A thirty-three gene-based signature predicts lymph node metastasis and prognosis in patients with gastric cancer

Recently, several studies have indicated the great potential of gene expression signature of the primary tumor in predicting lymph node metastasis; however, few current gene biomarkers can predict lymph node status and prognosis in gastric cancer (GC). Thus, we used the RNA-seq data from The Cancer Genome Atlas (TCGA) to identify differentially expressed genes between pathological lymph node-negative (pN0) and positive (pN+) patients and to establish a gene signature that could predict lymph node metastasis. Meanwhile, the robustness of identified gene signatures was validated in an independent dataset Asian Cancer Research Group (n = 300). In this study, our thirty-three gene-based signature was highly correlated with lymph node metastasis and could successfully discriminate pN + patients in the training set (Area under the receiver operating characteristic curve = 0.951). Moreover, Disease-free survival (P = 0.0029) and overall survival (P = 0.026) were significantly worse in high-risk compared with low-risk patients overall and when confined to pN0 patients only (P < 0.0001). Of note, this gene signature also proved useful in predicting lymph node status and survival in the validation cohort. The present study suggests a thirty-three gene-based signature that could effectively predict lymph node metastasis and prognosis in GC.

Hsa_circ_0001020 Serves as a Potential Biomarker for Gastric Cancer Screening and Prognosis

Circular RNAs (circRNAs) are an intriguing class of RNAs with covalently closed-loop structures. With characteristics of high stability and disease-specific expression, circRNAs are emerging as ideal targets for cancer therapy. However, the screening utility and clinical value of circRNAs in gastric cancer (GC) remain largely elusive. We detected levels of hsa_circ_0001020 in cell lines and tissue and plasma samples and investigated its clinicopathological correlations. Kaplan-Meier survival curves and regression analyses were used to analyze its prognostic value. Receiver operating characteristic curves and biomarker combinations were examined to verify its screening value. Bioinformatics analysis was also performed to predict potential biological functions. Our tests found that hsa_circ_0001020 was significantly upregulated in GC cell lines, GC tissue samples, and even in plasma. High hsa_circ_0001020 expression levels in GC tissues were significantly associated with distal metastasis and blood carbohydrate antigen 19-9 (CA19-9). GC patients with high hsa_circ_0001020 had a lower overall survival and disease-free survival time than the low levels. Regression analysis suggested that the level of hsa_circ_0001020 expression was an independent prognostic factor for survival time. As a biomarker for GC, hsa_circ_0001020 showed a superior AUC, sensitivity, and specificity than carcinoembryonic antigen and CA19-9, and was suitable for combination with clinical tumor biomarkers. Bioinformatics analysis provided valuable clues for the possible oncogenic pathways of GC, such as the FoxO and p53 signaling pathways. In conclusion, our study found that hsa_circ_0001020 in GC could be a reliable biomarker to screen for GC and predict prognosis.

Impact of the extent of negative lymph nodes in gastric adenocarcinoma undergoing primary surgical resection: An institutional report

BACKGROUND

Sub-total/total gastrectomy with lymph node dissection (LND) remains an effective therapeutic strategy for resectable gastric adenocarcinomas (GACs). Despite the prognostic significance of positive lymph nodes (PLNs) defined in N-status, few have appraised the impacts of negative lymph nodes (NLNs) and the percentage of NLN (=number of NLNs/number of total lymph nodes [TLNs], %), as well as the extent of TLNs to be dissected in GACs.

METHODS

We retrospectively analyzed 62 GAC patients (mean age of 67.1 years; 41 men) undergoing primary sub-total/total gastrectomy from a single institute. Candidate variables, including the number of NLNs (≤9 and >9) and the percentage of NLN (≤37.5, 37.5-80.6 and >80.6, %), were evaluated to determine their prognostic impacts and hazard ratios (HRs).

RESULTS

Under the multivariate Cox proportional-hazards regression model, tumor length exceeding 4 cm (p = 0.017; HR = 2.828), perineural invasion (p = 0.037; HR = 3.182), and lower percentage of NLN (p = 0.016 and p = 0.060; HRs = 1.000, 0.327, and 0.333 for subgroups ≤37.5, 37.5-80.6, and >80.6, respectively) were three independent predictors with elevated HRs for poor prognosis. GAC patients with the percentage of NLN > 80.6 were highly related to those with NLNs > 9 (p < 0.001), and GAC patients with NLNs > 9 were highly related to those with TLNs > 15 (p < 0.001). For all 62 GAC or 42 N(+) GAC patients, those who underwent LND with TLNs>15 tended to have more PLNs (p = 0.018, p = 0.003) and more NLNs (p < 0.001, p = 0.029) than did those with TLNs ≤ 15. Among the 42 GAC patients with TLNs > 15, a lower percentage of NLN (p = 0.026 and p = 0.015; HRs = 1.000, 0.272, and 0.180 for subgroups ≤37.5, 37.5-80.6, and >80.6, respectively) remained an independent predictor of poor prognosis.

CONCLUSION

The percentage of NLN could predict the prognosis of GAC patients properly. However, an accurate percentage of NLN needs a minimal requirement of TLNs > 15 to detect an adequate number of PLNs and sufficient number of NLNs.

Clinical Relevance of Splenic Hilar Lymph Node Dissection for Proximal Gastric Cancer: A Propensity Score-Matching Case-Control Study

BACKGROUND

The application of splenic hilar lymph node (no. 10 LN) dissection (no. 10 LND) for proximal gastric cancer (PGC) remains controversial. This study aimed to investigate the clinical relevance of no. 10 LND from the perspective of long-term survival.

METHODS

The main study population included 995 previously untreated patients who underwent laparoscopic radical total gastrectomy between January 2008 and December 2014. Of these 995 patients, 564 underwent no. 10 LND (no. 10D+ group) and the remaining 431 patients did not (no. 10D- group). Propensity score-matching was applied to reduce the effects of confounding factors. The study end points were overall survival (OS) and disease-free survival (DFS). Additionally, 39 patients who received neoadjuvant chemotherapy during the same period also were included as a separate population for analysis.

RESULTS

The metastasis rate for no. 10 LN was 10.5 % (59/564). No significant differences were observed in intra- and postoperative complications nor in mortality between the no. 10D+ and no. 10D- groups (all P > 0.05). After 1:1 matching, the two groups were comparable in clinicopathologic characteristics. The no. 10D+ group had significantly better survival than the no. 10D- group (5-year OS: 63.3 % vs 52.2 %, P = 0.003; 5-year DFS: 60.4 % vs 48.1 %, P = 0.013). For the patients who received neoadjuvant chemotherapy, the 5-year OS rates in the no. 10D+ and no. 10D- groups were respectively 50.6 % and 31.3 % (P = 0.150) and the 5-year DFS rates were respectively 51.5 % and 31.3 % (P = 0.123).

CONCLUSIONS

Patients with untreated PGC may achieve the benefit of long-term survival from no. 10 LND. For patients with PGC who undergo neoadjuvant chemotherapy, no. 10 LND may not bring survival benefits. However, further validation with a large-sample study is needed.

Prognostic value of occult lymph node metastases in patients with completely resected esophageal squamous cell carcinoma

To investigate the prognostic value of occult lymph node metastases (OLNMs) in patients with pathologically lymph node negative (pN0) esophageal squamous cell carcinoma (ESCC). OLNMs were detected in 516 pN0 ESCC patients by immunohistochemical staining. The correlation between the clinicopathological features and OLNM, and the prognostic value of OLNM was explored. Eighty-eight patients (17.1%) had OLNMs, including 37 patients with isolated tumor cells (ITCs), 49 patients with micrometastases, and 2 patients with macrometastases (> 2 mm). The OLNM-positive group had poorer differentiation and a more advanced pT category. The 5-year overall survival and disease-free survival for patients with OLNMs were significantly worse than those of IHC-negative patients (P < 0.001), but similar to those of the pN1 patients (P > 0.05). The multivariate analysis showed that OLNM was an independent prognostic factor. In subgroup analyses, the IHC-negative patients had significant survival advantages compared with the ITC group and the micrometastasis group, whereas the survival for the ITC group was similar to that of the micrometastasis group. IHC staining in pN0 ESCC patients might help to identify patients at high risk of death after resection, and ITCs in the lymph nodes appear to have a prognostic value equal to that of micrometastases.

Occult Tumour Cells in Lymph Nodes from Gastric Cancer Patients: Should Isolated Tumour Cells Also Be Considered?

INTRODUCTION

Regional lymph node metastasis is an important prognostic factor for patients with gastric cancer. Occult tumour cells (OTCs), including either micrometastases (MMs) or isolated tumour cells (ITCs), may be a key factor in the development of cancer recurrence in pN0 patients.

AIMS

We aimed to determine the frequency and prognostic significance for disease recurrence of OTCs.

MATERIALS AND METHODS

This retrospective cohort study included all consecutive patients with pN0 gastric adenocarcinoma between January 2000 and December 2011 (n = 73). Immunohistochemistry using the pan-cytokeratin antibody AE1/AE3 was used to detect OTCs in 1257 isolated lymph nodes.

RESULTS

OTCs were identified in 30 patients (41%), including 20 cases with MMs (27%) and 10 cases with ITCs (14%). Disease recurrence and cancer-related death were observed in 24 (33%) and 20 patients (27%), respectively, and both were significantly associated with the detection of OTCs. A significant difference was also observed for the mean survival time between patients with OTCs and those without OTCs [100 vs 158 months (p = 0.015)]. The presence of OTCs was statistically significantly associated with the Lauren classification, tumour size and lymphatic permeation. Multivariate analyses revealed that only age, T stage and the presence of ITCs in lymph nodes were independent factors for recurrence. The presence of ITCs increased the risk for recurrence by 11.1-fold.

CONCLUSIONS

In a significant proportion of patients diagnosed as stage pN0, OTCs may be identified in lymph nodes if carefully searched for, which can negatively affect their prognosis. The presence of ITCs was found to be an independent factor for recurrence and after proper validation should be considered during lymph node assessment for prognosis definition.

Impact of multisection and immunohistochemistry in lymph node staging of Gastric Carcinoma - Case series

Gastric carcinoma (GC) locoregional recurrence may occur even in cases where the tumor has been completely resected, possibly due to lymph node (LN) micrometastases. It is estimated that in 10% to 30% of cases, LN micrometastases are not detected by a conventional method for histological assessment of LN metastases with hematoxylin-eosin (HE). A cross-sectional study assessed 51 patients with GC by histological evaluation of the LN micrometastases through LN multi sectioning associated with immunohistochemistry analysis with monoclonal antibodies AE1 and AE3. Total gastrectomy was performed in 51% of patients. The total number of resected LN nodes was 1698, with a mean number of resected LN of 33.3 ± 13.2 per surgical specimen, of which 187 had metastasis. After the application of LN multisection and immunohistochemistry, LN micrometastases were found in 45.1% of the cases. LN staging changed in 29.4%, and tumor staging changed in 23.5% of the cases. In patients initially staged as pN0, LN staging and tumor staging changed, both in 19.2% of the cases. In patients initially staged as pN1 or more, LN staging changed in 40.0% of them, and tumor staging changed in 28.0% of the cases. The accuracy of HE for the histological staging of LN tumoral involvement was 76%, which was considered insufficient for CG patients staging. Investigation of LN micrometastasis through LN multisection and immunohistochemistry should be performed, particularly in cases where the presence of blood and lymphatic vessel invasion has been identified after conventional histological analysis, as well as in patients with advanced GC.

Clinical significance of skip lymph-node metastasis in pN1 gastric-cancer patients after curative surgery

BACKGROUND

In addition to the stepwise manner of lymph-node metastasis from the primary tumour, the skip lymph-node metastasis (SLNM) was identified as a low-incidence metastasis of gastric cancer (GC). So far, both the mechanism and outcome of SLNM have not been elucidated completely. The purpose of this study was to analyse the clinical significance and the potential mechanism of SLNM in GC patients who had lymph-node metastasis.

METHODS

Clinicopathological data and follow-up information of 505 GC patients who had lymph-node metastasis were analysed to demonstrate the significance of SLNM in evaluating the prognostic outcome. According to the pathological results, all GC patients who had lymph-node metastasis were categorized into three groups: patients with the perigastric lymph-node metastasis, patients with the perigastric and extragastric lymph-node metastasis and patients with SLNM.Results: Among the 505 GC patients who had lymph-node metastasis, 24 (4.8%) had pathologically identified SLNM. The location of lymph-node metastasis was not significantly associated with 5-year survival rate and overall survival (OS) (P = 0.194). The stratified survival analysis results showed that the status of SLNM was significantly associated with the OS in patients with pN1 GC (P = 0.001). The median OS was significantly shorter in 19 pN1 GC patients with SLNM than in 100 patients with perigastric lymph-node metastasis (P < 0.001). The case-control matched logistic regression analysis results showed that tumour size (P = 0.002) was the only clinicopathological factor that may predict SLNM in pN1 GC patients undergoing curative surgery. Among the 19 pN1 GC patients with SLNM, 17 (89.5%) had metastatic lymph nodes along the common hepatic artery, around the celiac artery or in the hepatoduodenal ligament.

CONCLUSIONS

SLNM may be considered a potentially practicable indicator for prognosis among various subgroups of pN1 GC patients.

Aberrant Cytokeratin 20 mRNA Expression in Peripheral Blood and Lymph Nodes Indicates Micrometastasis and Poor Prognosis in Patients With Gastric Carcinoma

Several studies suggest that peripheral blood and lymph node micrometastases may be a causative factor for gastric cancer recurrence. Cytokeratin 20 shows enriched expression in intestinal epithelial cells. This study aimed to evaluate the clinical utility of monitoring cytokeratin 20 levels in peripheral blood and lymph nodes of patients with gastric cancer for detecting micrometastasis and predicting prognosis. We detected messenger RNA levels of cytokeratin 20 in gastric cancer cell lines and in the peripheral blood of 125 patients (85 patients with gastric cancer and 40 patients with benign neoplasm) by fluorescence quantitative real-time polymerase chain reaction both before and after radical resection. In all, 1586 lymph node samples from 85 patients with gastric cancer were evaluated for cytokeratin 20 expression using real-time polymerase chain reaction, as well as by immunohistochemistry staining with anti-pan-keratin and anti-cytokeratin 20 antibodies. All patients underwent follow-up until cancer-related death or for more than 3 years after tumor resection. We found that elevated cytokeratin 20 expression in peripheral blood as detected by quantitative real-time polymerase chain reaction closely correlates with poor clinicopathological characteristics. Detecting cytokeratin 20 messenger RNA in the lymph nodes by quantitative real-time polymerase chain reaction enabled more accurate determination of the clinicopathological staging of gastric cancer, best treatment approach, and prognosis. Our findings show that patients with increased cytokeratin 20 messenger RNA expression in the peripheral blood or lymph nodes have a shorter time to recurrence and poorer overall survival.

Characterization of an orthotopic gastric cancer mouse model with lymph node and organ metastases using bioluminescence imaging

Lymph node (LN) metastasis of gastric cancer (GC) is the strongest prognostic indicator for this disease; however, the majority of the LN metastasis profiles of GC remain unknown, which notably hinders the therapeutic efficacy in clinic. In the present study, an orthotopic model of human GC was established for investigation of time-dependent LN metastasis patterns in mice. Luciferase-expressing NCI-N87 human GC cells were injected into the subserosa of the gastric body, resulting in a tumor formation rate of 100%. LN metastasis at four different anatomical positions in the abdomen were characterized until week 10 after tumor cell injection using sensitive bioluminescence imaging and histopathological analyses. Skip LN metastases were observed at later stages (weeks 8-10) of the experiment. Metastases in other major organs, including liver, spleen and lung, were also examined. Characterization of this orthotopic GC model and metastasis patterns in LNs and major organs should aid in the preclinical GC research regarding the metastatic mechanism and drug development.

Optimal management of resected gastric cancer

Although advances in medical treatment for gastric cancer (GC) have been made, surgery remains the mainstay of cure for patients with localized disease. Improvement in surgical modalities leads to increased chance of cure for resected patients, but a non-negligible number of patients eventually relapse. On this basis, it has been hypothesized that the addition of complementary systemic or local treatments (such as chemotherapy and radiotherapy) could help in improving patients' survival by reducing the risk of recurrence. Several studies have tried to identify the best approach in localized GC: some of them have assessed the role of perioperative chemotherapy [CT] with different drug combinations, while others have focused on the benefit obtained by addition of radiotherapy, whose role is still under investigation. In particular, the role of chemoradiotherapy, both in adjuvant and neoadjuvant settings, is still uncertain. In the last few years, several clinicopathological and molecular factors have been investigated and identified as potential prognostic markers in GC. Many of these factors could have influenced the outcome of patients receiving combined treatments in the abovementioned studies. Patients have not been generally distinguished by the site of disease (esophageal, gastric and junctional cancers) and surgical approach, making data difficult to be interpreted. The purpose of this review was to shed light on these highly controversial topics.

Current status of lymph node micrometastasis in gastric cancer

Lymph node metastasis is one of the most important prognostic factors in patients with gastric cancer. An inadequate number of dissected lymph nodes is an independent risk factor affecting recurrence, even in patients who are node negative. Oddly, certain early-stage patients still experience recurrence or metastasis within a short time, even if they have undergone standard radical mastectomy. Many researchers have attributed these adverse events to lymph node micrometastasis (LNM), which is defined as a microscopic deposit of malignant cells of less than 2 mm in diameter. With the development of diagnostic tools such as immunohistochemistry and reverse transcription-polymerase chain reaction, the rate of detection of LNM has been constantly increasing. Although there is no clear consensus about risk factors for or the definitive clinical significance of LNM, the clinical impact of LNM is remarkable in gastric cancer. For minimally invasive treatment in particular, such as endoscopic submucosal dissection and laparoscopic surgery, accurate diagnosis of LNM is regarded as the potential key to maintaining the balance between curability and safety. This review provides an overview of the definition, detection and significance of LNM in gastric cancer. We also summarize several attention-drawing controversies regarding the treatment of patients who may have LNM.

Long-term survival differences in gastric cancer after D2 lymphadenectomy and an improved assessment of resectability

Objective. The purpose of this work is to compare the long-term survival between a control group with mostly D1 lymphadenectomy and a study group with mostly D2 lymphadenectomy. Materials and Methods. We analyzed consecutive cases operated by a single surgeon performing mostly D2 lymphadenectomy and a control group of consecutive gastric cancer patients operated by a group of surgeons, performing mostly D1 lymphadenectomy, in a period when D2 lymphadenectomy was not the standard and was introduced as a new technique in our center. Results. We found 30,56% D2 lymphadenectomy in the control groups and 85,1% in the study group. At a five years interval from surgery the control group had no survivors, while the study group had 8 (20%) survivors. Conclusions. The spleen and pancreas preserving D2 lymphadenectomy done by experienced surgeons, according to the current guidelines in order to select operable patients improves the overall survival of such gastric cancer patients.

N staging: the role of the pathologist

Gastric cancer is the second cause of cancer-related mortality worldwide. Metastases, including lymph nodes ones, heavily influence the prognosis of this disease. The pathological detection of positive lymph nodes is pivotal for an optimal prognostication and clinical management of affected individuals. Several factors influence the pathological investigation of surgical specimens, ultimately affecting the number of retrieved lymph nodes and, with it, the reliability of N staging. The pathologist plays a central role in optimizing this process. Factors influencing lymph node retrieval and analysis will be herein reviewed, together with the procedures adopted for an optimal pathological analysis of lymph nodes in gastric cancer.

DETECTION OF OCCULT LYMPH NODE TUMOR CELLS IN NODE-NEGATIVE GASTRIC CANCER PATIENTS

BACKGROUND

The presence of lymph nodes metastasis is one of the most important prognostic indicators in gastric cancer. The micrometastases have been studied as prognostic factor in gastric cancer, which are related to decrease overall survival and increased risk of recurrence. However, their identification is limited by conventional methodology, since they can be overlooked after routine staining.

AIM

To investigate the presence of occult tumor cells using cytokeratin (CK) AE1/AE3 immunostaining in gastric cancer patients histologically lymph node negative (pN0) by H&E.

METHODS

Forty patients (T1-T4N0) submitted to a potentially curative gastrectomy with D2 lymphadenectomy were evaluated. The results for metastases, micrometastases and isolated tumor cells were also associated to clinicopathological characteristics and their impact on stage grouping. Tumor deposits within lymph nodes were defined according to the tumor-node-metastases guidelines (7th TNM).

RESULTS

A total of 1439 lymph nodes were obtained (~36 per patient). Tumor cells were detected by immunohistochemistry in 24 lymph nodes from 12 patients (30%). Neoplasic cells were detected as a single or cluster tumor cells. Tumor (p=0.002), venous (p=0.016), lymphatic (p=0.006) and perineural invasions (p=0.04), as well as peritumoral lymphocytic response (p=0.012) were correlated to CK-positive immunostaining tumor cells in originally negative lymph nodes by H&E. The histologic stage of two patients was upstaged from stage IB to stage IIA. Four of the 28 CK-negative patients (14.3%) and three among 12 CK-positive patients (25%) had disease recurrence (p=0.65).

CONCLUSION

The CK-immunostaining is an effective method for detecting occult tumor cells in lymph nodes and may be recommended to precisely determine tumor stage. It may be useful as supplement to H&E routine to provide better pathological staging.

Increasing the Number of Examined Lymph Nodes is a Prerequisite for Improvement in the Accurate Evaluation of Overall Survival of Node-Negative Gastric Cancer Patients

BACKGROUND

This study aims to elucidate whether increasing the number of examined lymph nodes (NELN) is mandatory for the accurate prognosis of node-negative gastric cancer (GC) patients after curative gastrectomy in Eastern countries (China and Japan).

METHODS

The clinicopathological data of 2455 GC patients (including 1137 node-negative cases) were included to demonstrate whether a minimum NELN is inevitable for guaranteeing the accurate prognosis of node-negative GC patients after curative gastrectomy.

RESULTS

Survival analyses revealed that the NELN significantly positively correlated with overall survival (p < 0.001) and was an independent prognostic predictor (hazard ratio 0.447; p = 0.025) of 1137 node-negative GC patients. Stratum analysis within the Kaplan-Meier method showed that sex, tumor size, and extent of lymphadenectomy did not affect the NELN in predicting the prognosis of all node-negative GC patients. Stage migration was mainly detected in the subgroup of node-negative GC Chinese patients who presented considerably lower mean NELN and more advanced staging than patients from Japan. The NELN was identified as the most intensively independent predictor of prognosis of 600 node-negative GC patients from China, with the smallest Akaike information criterion (176.964) and Bayesian information criterion values (194.552). These findings indicate that increasing the NELN is a prerequisite to guaranteeing precise TNM classification.

CONCLUSIONS

The NELN should be considered a mandatory requirement for improving the accuracy of prognostic evaluation of GC patients, especially for advanced-stage patients.

Clinical significance of lymphadenectomy in patients with gastric cancer

Approximately thirty percent of patients with gastric cancer undergo an avoidable lymph node dissection with a higher rate of postoperative complication. Comparing the D1 and D2 dissections, it was found that there is a significant difference in morbidity, favoured D1 dissection without any difference in overall survival. Subgroup analysis of patients with T3 tumor shows a survival difference favoring D2 lymphadenectomy, and there is a better gastric cancer-related death and non-statistically significant improvement of survival for node-positive disease in patients with D2 dissection. However, the extended lymphadenectomy could improve stage-specific survival owing to the stage migration phenomenon. The deployment of centralization and application of national guidelines could improve the surgical outcomes. The Japanese and European guidelines enclose the D2 lymphadenectomy as the gold standard in R0 resection. In the individualized, stage-adapted gastric cancer surgery the Maruyama computer program (MCP) can estimate lymph node involvement preoperatively with high accuracy and in addition the Maruyama Index less than 5 has a better impact on survival, than D-level guided surgery. For these reasons, the preoperative application of MCP is recommended routinely, with an aim to perform “low Maruyama Index surgery”. The sentinel lymph node biopsy (SNB) may decrease the number of redundant lymphadenectomy intraoperatively with a high detection rate (93.7%) and an accuracy of 92%. More accurate stage-adapted surgery could be performed using the MCP and SNB in parallel fashion in gastric cancer.