Clinical significance of lymph node micrometastasis in gastric cancer

TUMOR MARKERS EXPRESSION LEVELS IN GASTRIC CANCER PATIENT'S PERIPHERAL BLOOD BY RT-PCR ASSESSMENT

BACKGROUND

Hematological recurrence is the second most frequent cause of failure in the treatment of gastric cancer. The detection of circulating tumor markers in peripheral blood by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) method may be a useful tool to predict recurrence and determine the patient's prognosis. However, no consensus has been reached regarding the association between the tumor markers level in peripheral blood and its impact on patient survival.

AIMS

To evaluate the expression of the circulating tumor markers CK20 and MUC1 in peripheral blood samples from patients with gastric cancer by qRT-PCR, and to verify the association of their expression levels with clinicopathological characteristics and survival.

METHODS

A total of 31 patients with gastric adenocarcinoma were prospectively included in this study. CK20 and MUC1 expression levels were analyzed from peripheral blood by the qRT-PCR technique.

RESULTS

There was no statistically significant (p>0.05) association between CK20 expression levels and clinical, pathological, and surgical features. Higher MUC1 expression levels were associated with female patients (p=0.01). There was a correlation between both gene levels (R=0.81, p<0.001), and CK20 level and tumor size (R=0.39, p=0.034).

CONCLUSIONS

CK20 and MUC1 expression levels could be assessed by qRT-PCR from total peripheral blood samples of patients with gastric cancer. CK20 levels were correlated to MUC1 levels as well as to tumor size. There was no difference in disease-free survival and overall survival regarding both genetic markers expression in this series.

Long-Term Impact of D2 Lymphadenectomy during Gastrectomy for Cancer: Individual Patient Data Meta-Analysis and Restricted Mean Survival Time Estimation

BACKGROUND

Debate exists concerning the impact of D2 vs. D1 lymphadenectomy on long-term oncological outcomes after gastrectomy for cancer.

METHODS

PubMed, MEDLINE, Scopus, and Web of Science were searched and randomized controlled trials (RCTs) analyzing the effect of D2 vs. D1 on survival were included. Overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) were assessed. Restricted mean survival time difference (RMSTD) and 95% confidence intervals (CI) were used as effect size measures.

RESULTS

Five RCTs (1653 patients) were included. Overall, 805 (48.7%) underwent D2 lymphadenectomy. The RMSTD OS analysis shows that at 60-month follow-up, D2 patients lived 1.8 months (95% CI -4.2, 0.7; p = 0.14) longer on average compared to D1 patients. Similarly, 60-month CSS (1.2 months, 95% CI -3.9, 5.7; p = 0.72) and DFS (0.8 months, 95% CI -1.7, 3.4; p = 0.53) tended to be improved for D2 vs. D1 lymphadenectomy.

CONCLUSIONS

Compared to D1, D2 lymphadenectomy is associated with a clinical trend toward improved OS, CSS, and DFS at 60-month follow-up.

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.

Pathological and oncological outcomes of pylorus-preserving versus conventional distal gastrectomy in early gastric cancer: a systematic review and meta-analysis

Background

Pylorus-preserving gastrectomy (PPG) is a function-preserving surgery for the treatment of early gastric cancer (EGC) in the middle third of the stomach. According to the literature reports, PPG decreases the incidence of dumping syndrome, bile reflux, gallstone formation, and nutritional deficit compared with conventional distal gastrectomy (CDG). However, the debates about PPG have been dominated by the incomplete lymphadenectomy and oncological safety. We carried out a systematic review and meta-analysis to evaluate the pathological and oncological outcomes of PPG.

Methods

The protocol was registered in PROSPERO under number CRD42022304677. Databases including PubMed, Embase, Web of Science, and the Cochrane Register of Controlled Trials were searched before February 21, 2022. The outcomes included the pooled odds ratios (ORs) for dichotomous variables and weighted mean differences (WMDs) for continuous variables. For all outcomes, 95% confidence intervals (CIs) were calculated. Meta-analysis was performed using STATA software (Stata 14, Stata Corporation, Texas) and Review Manager 5.4.

Results

A total of 4500 patients from 16 studies were included. Compared with the CDG group, the PPG group had fewer lymph nodes harvested (WMD= −3.09; 95% CI −4.75 to −1.43; P < 0.001). Differences in the number of resected lymph nodes were observed at stations No. 5, No. 6, No. 9, and No. 11p. There were no differences in lymph node metastasis at each station. Shorter proximal resection margins (WMD = −0.554; 95% CI −0.999 to −0.108; P = 0.015) and distal resection margins (WMD = −1.569; 95% CI −3.132 to −0.007; P = 0.049) were observed in the PPG group. There were no significant differences in pathological T1a stage (OR = 0.99; 95% CI 0.80 to 1.23; P = 0.88), T1b stage (OR = 1.01; 95% CI 0.81 to 1.26; P = 0.88), N0 stage (OR = 0.97; 95% CI 0.63 to 1.48; P = 0.88), tumor size (WMD = −0.10; 95% CI −0.25 to 0.05; P = 0.187), differentiated carcinoma (OR = 1.04; 95% CI 0.74 to 1.47; P = 0.812) or signet ring cell carcinoma (OR = 1.22; 95% CI 0.90 to 1.64; P = 0.198). No significant differences were observed between the groups in terms of overall survival (HR = 0.63; 95% CI 0.24 to 1.67; P = 0.852) or recurrence-free survival (HR = 0.29; 95% CI 0.03 to 2.67; P = 0.900).

Conclusions

The meta-analysis of existing evidence demonstrated that the survival outcomes of PPG may be comparable to those of CDG. However, fewer lymph nodes at stations in No. 5, No. 6, No. 9, and No. 11p were harvested with PPG. We also found shorter proximal resection margins and distal resection margins for PPG, meaning more remnant stomachs would be preserved in PPG.

Life prognosis of sentinel node navigation surgery for early-stage gastric cancer: Outcome of lymphatic basin dissection

BACKGROUND

Lymphatic basin dissection is a sentinel node biopsy method that is specific for gastric cancer. In this method, the dyed lymphatic system is dissected en bloc, and sentinel nodes are identified at the back table (ex vivo). Even with lymphatic basin dissection, blood flow to the residual stomach can be preserved, and function-preserving curative gastrectomy can be performed. The oncological safety of function-preserving curative gastrectomy combined with lymphatic basin dissection has not yet been fully investigated. We hypothesized that the oncological safety of sentinel node navigation surgery (SNNS) is not inferior to that of the guidelines.

AIM

To investigate the life prognosis of SNNS for gastric cancer in comparison with guidelines surgery.

METHODS

This was a retrospective cohort study. Patients were selected from gastric cancer patients who underwent sentinel node biopsy from April 1999 to March 2016. Patients from April 1999 to August 2008 were from the Department of Surgery II, Kanazawa University Hospital, and patients from August 2009 to March 2016 were from the Department of Surgical Oncology, Kanazawa Medical University Hospital. Patients who were diagnosed with gastric cancer, which was preoperatively diagnosed as superficial type (type 0), 5 cm or less in length, clinical T1-2 and node negative, and underwent various gastrectomies guided by sentinel node navigation were retrospectively collected. The overall survival (OS) and relapse-free survival (RFS) of these patients (SNNS group) were investigated. Patients with gastric cancer of the same stage and who underwent guidelines gastrectomy with standard nodal dissection were also selected as the control group.

RESULTS

A total of 239 patients in the SNNS group and 423 patients in the control group were included. Pathological nodal metastasis was observed in 10.5% and 10.4% of the SNNS and control groups, respectively. The diagnostic abilities of sentinel node biopsy were 84% and 98.6% for sensitivity and accuracy, respectively. In the SNNS group, 81.6% of patients underwent modified gastrectomy or function-preserving curative gastrectomy with lymphatic basin dissection, in which the extent of nodal dissection was further reduced compared to the guidelines. The OS rate in the SNNS group was 96.8% at 5 years and was significantly better than 91.3% in the control group (P = 0.0014). The RFS rates were equal in both groups. After propensity score matching, there were 231 patients in both groups, and the cumulative recurrence rate was 0.43% at 5 years in the SNNS group and 1.30% in the control group, which was not statistically different.

CONCLUSION

The oncological safety of patients who undergo gastrectomy guided by sentinel node navigation is not inferior to that of the guidelines surgery.

Lymph node micrometastasis of poorly differentiated node-negative gastric cancer risks a worse-than-expected survival outcome under standard management algorithm

BACKGROUND

Investigation of lymph node micrometastasis (mN) of gastric cancer has been focused on either T1 disease or T1-4N0 disease. Yet, it is unclear whether standard management algorithm toward poorly differentiated gastric cancer (PDGC) is more vulnerable to existence of mN, given its inherently biological aggressiveness, as compared with other histological types.

PATIENTS AND METHODS

A surgical series (n = 3456) of gastric cancer categorized by histological differentiation was enrolled to analyze survival stratification. Of them, a cohort of T1-T4 N0 PDGC (n = 100) were subjected to cytokeratin immunohistochemistry, a surrogate of mN.

RESULTS

Cancer-specific survival by AJCC8 staging system could be nicely differentiated in both well-/moderately differentiated and signet ring cell types, while those between stage IA versus IB (p = 0.105), and stage IB versus IIA (p = 0.141) in PDGC could not. Thirteen (13%) out of 100 node-negative PDGC cases exhibited mN, with 5, 2, 5 and 1 cases occurring in T1, T2, T3, and T4 stage, respectively, without identifiable contributing factors. Prognostic performance of AJCC8 working upon PDGC became more discriminative by incorporating mN, as hazard ratio of stage IIIC referenced to stage IA increased from 43 to 78.

CONCLUSION

Defective discriminative survival of PDGC by standard staging algorithm prompted us to survey mN occurring in T1-T4N0 PDGC. The prognostic performance of AJCC8 working upon PDGC was enhanced by incorporating mN. As so, we recommend documentation of mN exclusively on node-negative PDGC that helps unveil stage migration phenomenon and switch to appropriate adjuvant therapy in need.

Combination of the ratio between metastatic and harvested lymph nodes and negative lymph node count as a prognostic indicator in advanced gastric cancer: a retrospective cohort study

Background

The aim of our study was to examine the impact of the combination of the ratio between metastatic and harvested lymph nodes (RML) and negative lymph node (NLN) count on overall survival (OS) in patients with advanced gastric cancer (GC).

Methods

The clinicopathological data of 2,952 advanced GC patients who received curative resection between 1994 and 2015 were collected. They were divided into four groups according to the RML: 0, 0-0.1, 0.1-0.4, and >0.4. We distinguished survival differences through Kaplan-Meier analysis among the subgroups to investigate the impacts of the RML on OS in advanced GC patients. OS was examined according to clinicopathological variables. Spearman's correlation coefficient was used to assess the relationships between the RML and metastatic lymph node (MLN) count and NLN count.

Results

A total of 1,182 patients were enrolled into the study. The median follow-up time was 39 months (interquartile range 20 to 68 months). The 5-year OS rate of all 1,182 GC patients was 54.4%. Kaplan-Meier survival analysis showed that the median OS declined significantly with increasing RML (5-year survival rate 81.2% vs. 69.1% vs. 42.8% vs. 13.1%, P<0.001). As the NLN count increased, the survival rate of GC patients increased (5-year survival rate 12.8% vs. 25.2% vs. 60.2%, P<0.05). The RML, not NLN count, was identified as an independent factor for OS (P<0.001) through multivariate analysis. Spearman correlation analysis suggested that the RML was positively correlated with the number of MLNs (ρ=0.973, P<0.001) and inversely associated with the NLN count (ρ=-0.513, P<0.001).

Conclusions

The RML is an independent prognostic predictor of OS in advanced GC patients, and the NLN count may serve as a supplementary strategy for the present tumor-node-metastasis (TNM) classification to further improve the prognostic prediction efficiency. The combination of the RML and NLN count should be an important predictor for current clinical applications.

Pathologic Lymph Node Staging of Gastric Cancer

OBJECTIVES

The TNM classification is the main tool for lymph node (LN) staging in gastric cancer (GC). However, alternative LN staging systems have been proposed, and the role of features other than the number of metastatic LNs is being investigated. Our aim is to discuss the main challenges of LN assessment in GC.

METHODS

Comprehensive review of the literature on alternative LN staging systems, examined LNs, sentinel LN (SLN) biopsy, LN micrometastases (LNMIs), extracapsular extension (ECE), and tumor deposits (TDs) in GC.

RESULTS

Many controversies exist regarding LN assessment in GC. The TNM classification shows excellent prognostic performance, but alternative prognostic methods such as the LN ratio or log odds of positive LNs have demonstrated to be better than the TNM system in terms of prognostic accuracy. The value of SLN biopsy and LNMIs in GC is still unclear, and several challenges concerning their clinical impact and pathologic analysis must be overcome before their introduction in clinical practice. Most authors have identified ECE and TDs as independent prognostic factors for survival in GC.

CONCLUSIONS

Further studies should be performed to evaluate the impact of these features on the TNM classification and patient outcomes, as well as to standardize alternative LN staging systems.

A qualitative transcriptional signature of recurrence risk for stages II-III gastric cancer patients after surgical resection

BACKGROUND AND AIM

Metastasis is the leading cause of recurrence in gastric cancer. However, the imaging techniques and pathological examinations for tumor metastasis have a high false-positive rate or a high false-negative rate, and many proposed that metastasis-related molecular biomarkers can hardly be validated in independent datasets.

METHODS

We propose to use significantly stable gene pairs with reversal relative expression orderings (REOs) between non-metastasis and metastasis gastric cancer samples as the metastasis-related gene pairs. Based on the REOs of these gene pairs, we developed a qualitative transcriptional signature for predicting the recurrence risk of stages II-III gastric cancer patients after surgical resection.

RESULTS

A REOs-based signature, consisting of 19 gene pairs (19-GPS), was selected from 77 stages II-III gastric cancer patients and validated in two independent datasets. Samples in the high-risk group had shorter disease-free survival time and overall survival time than those in the low-risk group. Differentially expressed genes (DEGs) between the high- and low-risk groups classified by 19-GPS were highly reproducible comparing with those between lymph node metastasis and lymph node non-metastasis groups. Functional enrichment analysis showed that these DEGs were significantly enriched in metastasis-related pathways, such as PI3K-Akt and Rap1 signaling pathways. The multi-omics analyses suggested that the epigenetic and genomic features might cause transcriptional differences between two subgroups, which help to characterize the mechanism of gastric cancer metastasis.

CONCLUSIONS

The signature could robustly identify patients at high recurrence risk after resection surgery, and the multi-omics analyses might aid in revealing the metastasis-related characteristics of gastric cancer.

Lymphovascular Invasion: Traditional but Vital and Sensible Prognostic Factor in Early Gastric Cancer

BACKGROUND

Although patients with early gastric cancer have good prognosis, recurrence after treatment may occur. Lymphovascular invasion (LVI) in gastric cancer has long been suggested as a poor prognostic indicator. This study sought to evaluate the prognostic effect of LVI in patients with early gastric cancer.

METHODS

From 2005 to 2016, 6516 patients with early gastric cancer who underwent radical gastrectomy were analyzed. The patients were categorized according to LVI and lymph node (LN) status.

RESULTS

LVI was present in 853 patients (13.1%). Patients with LVI or LN metastasis had more aggressive tumor characteristics than patients without both LVI and LN metastasis. The overall and relapse-free survival in patients with LVI were significantly worse than in patients without LVI. When we compared the survival rate of patients stratified by LVI and LN status, there was a significant overall and relapse-free survival difference between patients without both LVI and LN metastasis compared with those with LVI but without LN metastasis (p < 0.001). The overall and relapse-free survival of patients with LVI but without LN metastasis were similar to those without LVI but with LN metastasis (p = 0.818). Patients with LVI or LN metastasis showed a high frequency of recurrence (p < 0.001). Multivariate analysis showed that LVI and LN status were independent risk factors for relapse-free survival of early gastric cancer patients.

CONCLUSIONS

Early gastric cancer with LVI is associated with poor prognosis and frequent recurrence. When predicting the prognosis of patients with early gastric cancer, LVI should be considered.

Burgeoning study of sentinel-node analysis on management of early gastric cancer after endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an organ-preserving alternative to surgical resection of early gastric cancer. However, even with ESD yielding en-bloc resection specimens, there are concerns regarding tumor spread such as with larger lesions, ulcerated lesions, undifferentiated pathology and submucosal invasion. Sentinel node navigational surgery (SNNS) when combined with ESD offers a minimally invasive alternative to the traditional extended gastrectomy and lymphadenectomy if lack of lymph node spread can be confirmed. This would have a clear advantage in terms of potential complications and quality of life. However, SNNS, though useful in other malignancies such as breast cancer and melanoma, may not have a sufficient sensitivity for malignancy and negative predictive value in EGC to justify this as standard practice after ESD. The results of SNNS may improve with greater standardization and more involved dissection, technological innovations and more experience and validation such that the paradigm for post-ESD resection of EGC may change and include SNNS.

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.

Sentinel lymph node detection for gastric cancer: Promise or pitfall?

At present, optimal surgery for gastric cancer is still under debate, especially the extent of lymph node dissection. Gastrectomy with D1/D2 lymphadenectomy is standard treatment for resectable advanced gastric cancer. However, in early gastric cancer without lymph node metastasis, gastrectomy with D1/D2 lymphadenectomy may not be unnecessary, which could increases morbidity and mortality and reduces the quality of life (QOL). Therefore, the concept of sentinel lymph node could be applied in gastric cancer. But due to the complexity of gastric lymphatic drainage, there are still many issues under debate, such as suitable tracers, the method of mapping and collecting and the oncologic safety of sentinel node navigation surgery (SNNS). In addition, skip metastasis and unreliability of intraoperative pathological diagnosis are two main reasons for false negative cases. In this review, we summarize the current status and controversy of sentinel lymph node detection in gastric cancer, attempting to help with practical application. Further, we hold opinion that we should be cautious about performing sentinel lymph node detection in gastric cancer before an accurate and effective method occurs.

Cytomorphological Characterization of Individual Metastatic Tumor Cells from Gastrointestinal Cancer Patient Lymph Nodes with Imaging Flow Cytometry

The presence or absence of tumor cells within patient lymph nodes is an important prognostic indicator in a number of cancer types and an essential element of the staging process. However, patients with the same pathological stage will not necessarily have the same outcome. Therefore, additional factors may aid in identifying patients at a greater risk of developing metastasis. In this proof of principle study, initially, spiked tumor cells in rat lymph nodes were used to mimic a node with a small cancer deposit. Next, human lymph nodes were obtained from cancer patients for morphological characterization. Nodes were dissociated with a manual tissue homogenizer and stained with fluorescent antibodies against CD45 and Pan-Cytokeratin and then imaging flow cytometry (AMNIS ImageStreamX Mark II) was performed. We show here that imaging flow cytometry can be used for the detection and characterization of small numbers of cancer cells in lymph nodes and we also demonstrate the phenotypical and morphological characterization of cancer cells in gastrointestinal cancer patient lymph nodes. When used in addition to conventional histological techniques, this high throughput detection of tumor cells in lymph nodes may offer additional information assisting in the staging process with therapeutic and prognostic applications.

Effect of age on the clinical outcomes of patients with early gastric cancer with undifferentiated-type histology

BACKGROUND

Undifferentiated-type early gastric cancers account for a large proportion of gastric cancers in younger patients. Therefore, the clinical outcomes of endoscopic resection in younger patients are a major concern. We aimed to investigate the influence of age on lymph node metastasis and long-term survival after surgery for undifferentiated-type early gastric cancers.

METHODS

We identified 4,236 patients who underwent surgery for undifferentiated-type early gastric cancers. For each T stage, the correlation between age and lymph node metastasis was analyzed using a multivariate logistic regression. Lymph node metastasis rates were compared between younger (<40 years) and older patients (≥40 years) who fulfilled the expanded criteria for endoscopic resection. The Kaplan-Meier method was used to compare long-term survival between younger and older patients.

RESULTS

Younger age groups (20-29 and 30-39 years) had the highest lymph node metastasis rate within each T stage (5.7% and 5.7% for T1a, 26.3% and 24.1% for T1b, respectively). After adjusting for possible covariates, however, age did not have a significant effect on lymph node metastasis in either T stage (P = .127 for T1a, P = .114 for T1b). Among patients fulfilling the expanded indication for endoscopic resection, younger patients had a slightly higher lymph node metastasis rate compared with older patients (2.7% versus 2.0%), although this difference was not statistically significant. Although younger patients had a significantly better overall survival (P < .001), no significant age-related differences were observed in recurrence-free and disease-specific survival (P = .051 and P = .069) CONCLUSION: Endoscopic resection may be feasible in young patients with undifferentiated-type early gastric cancers because these patients share a similar lymph node metastasis rate and long-term survival outcomes with older patients.

Prognostic Significance of Solitary Lymphnode Metastasis and Micrometastasis in Gastric Cancer

Gastric cancer (GC) used to be one of the most common malignancies in the world and still is the second leading cause of malignancy-related death in the Far East. The most significant factors that were found to be associated with the clinical outcome in patients with non-metastatic (M₀) gastric cancer is tumor's depth of invasion, the presence and the extend of lymphnode involvement, as well as the histological type according to Lauren (intestinal or diffuse). Although it is generally accepted that D2 gastrectomy is the procedure of choice to achieve adequate oncologic excision, there are quite many concerns for its use in patients with early gastric cancer (EGC), where N_o or N₁ specimens are frequently reported. The last two decades, with the evolvement of cancer cell detection techniques, the attend of the medical community is focused on GC patients with solitary lymphnode metastasis (SLN) or micrometastasis (mM). There is a discussion whether SLN should be attributed as the “real” sentinel node (SN) and its projection on patients' survival. The aim of this study is to review the recent literature and attempt to clarify the clinical significance of SLN in gastric cancer.

Indication for endoscopic treatment based on the risk of lymph node metastasis in patients with Siewert type II/III early gastric cancer

BACKGROUND

Because of the poor prognosis of proximal gastric cancers, there is debate as to whether the conventional indications for endoscopic resection can be used.

METHODS

Among subjects who underwent surgery for esophagogastric junction or gastric cardia cancer, 256 patients with T1 type II/III of the Siewert classification were included in this study. The association of lymph node metastasis (LNM) with each variable was analyzed using logistic regression models. A receiver operating characteristic curve was used to determine the discriminatory ability of the model. Propensity score-matched non-cardia cancer patients were selected to compare LNM and long-term survival rates.

RESULTS

Of the 256 patients with T1 Siewert II/III gastric cancer, 21 (8.2%) had LNM. Because there was no LNM in T1a cancers, risk factors were analyzed only in patients with T1b. Tumor size (OR 1.42, 95% CI 1.10-1.82, P = 0.007) and lymphovascular invasion (LVI) (OR 5.13, 95% CI 1.88-14.06, P = 0.002) were determined to be predictors of LNM (sensitivity = 66.7% and specificity = 81.6%). Among patients without LVI, the groups with negligible risk for LNM were mucosa-confined cancer, or SM1 cancer with a tumor size ≤3 cm. No LNM was observed in patients satisfying the absolute or extended criteria for endoscopic resection of early gastric cancers. LNM and long-term survival rates of patients with Siewert II/III did not differ significantly compared with matched non-cardia cancer patients.

CONCLUSIONS

Tumor size and LVI were associated with LNM in patients with early Siewert type II/III gastric cancer, and the expanded indication for endoscopic resection may be used.

Novel surgical approach based on the sentinel node concept in patients with early gastric cancer

Recent prospective multicenter trials have demonstrated the clinical safety and efficacy of sentinel node navigation surgery (SNNS) in patients with early gastric cancer. Further, development of an intraoperative imaging system and an indocyanine green fluorescence imaging approach has been attracting attention as a novel tool for detection of the sentinel node (SN). The greatest advantage of an in vivo imaging system is that it visualizes SN and afferent lymphatic vessels from the primary tumor site more clearly than the conventional dye approach. Besides visualization of the SN, it is also essential to accurately assess the presence or absence of lymph node metastasis in the intraoperative management of SNNS. However, the clinical significance of lymph node micrometastasis (LNM) in patients with gastric cancer remains controversial. Reverse transcription‐polymerase chain reaction (RT‐PCR) is one of the representative assays used to identify LNM. A rapid RT‐PCR assay that completes the detection of LNM within approximately 40 minutes has recently been produced and applied in the clinical management of SNNS. From the viewpoint of surgical methods, modified laparoscopic and endoscopic cooperative surgery with non‐exposed approaches has recently been highlighted as a promising technique to prevent tumor dissemination caused by surgical procedures, and is likely to be clinically applied to SNNS in the future. When carrying out SNNS as a minimally invasive surgery, it is important to consider the balance between post‐surgical quality of life and curability. Future prospective studies on SNNS will greatly contribute to furthering its establishment as a beneficial procedure for patients with early gastric cancer.

A Risk-prediction Model Based on Lymph-node Metastasis for Incorporation Into a Treatment Algorithm for Signet Ring Cell-type Intramucosal Gastric Cancer

OBJECTIVE

The aim of the study was to develop a reliable and easy-to-use risk-scoring system (RSS) to predict lymph-node metastasis (LNM) and determine the feasibility of endoscopic submucosal dissection for mucosa-confined signet ring cell carcinomas (SRCs).

BACKGROUND

Fewer LNM and better survival rates have been reported for early gastric SRCs compared with other undifferentiated early gastric cancers (EGCs).

METHODS

Data from 1544 patients with mucosa-confined SRCs were reviewed. Stepwise logistic regression analysis determined the independent predictors of LNM. Risk scores were based on the final predictive factors for LNM, and performance was internally validated using a split-sample approach. External validation was also performed in an independent dataset (n = 208) to assess the discriminatory power of the RSS.

RESULTS

The overall LNM incidence was 3.8% (57/1544). Three risk factors (tumor size ≥1.7 cm, tumors of elevated type, and lymphatic-vascular involvement) were significantly associated with LNM. These factors were incorporated into the RSS, and were assigned scores ranging from 0 to 4. The area under the receiver-operating characteristic curve for predicting LNM after internal and external validation was 0.68 (95% confidence interval, 0.0793-0.2865) and 0.686 (95% confidence interval, 0.618-0.748), respectively. A score of 2 points was the optimal cut-off value for LNM prediction, and the overall diagnostic accuracy was 96%. LNM were found in 2.9% and 23.8% of the low and high-risk groups of the RSS, respectively.

CONCLUSIONS

A RSS may help to predict LNM and evaluate endoscopic submucosal dissection feasibility in patients with intramucosal SRC.

Clinical application and outcomes of sentinel node navigation surgery in patients with early gastric cancer

Sentinel node navigation surgery (SNNS) has been recognized as a minimally invasive tool for individualized lymphadenectomy in patients with early gastric cancer (EGC). The aim of this study was to compare clinicopathological factors, adverse events, and clinical outcomes between sentinel node mapping (SNM) and SN dissection (SND) groups and assess the clinical utility of SNNS in patients with EGC. The clinical data of 157 patients with EGC, diagnosed as clinical T1N0M0 with tumors ≤ 40 mm, undergoing SNNS between March 2004 and April 2016 were retrospectively reviewed. Twenty-seven patients were excluded from the analysis. In the remaining 130 patients, 59 and 71 patients underwent standard lymphadenectomy for SNM and SND, respectively. The sentinel node detection rate in the SNM and SND groups was 98.3% (58/59) and 100% (71/71), respectively. Two (3.5%), 15 (25.9%), and 41 (70.7%) patients having sentinel nodes underwent total gastrectomy, proximal gastrectomy (PG), and distal gastrectomy (DG), respectively, in the SNM group. One (1.4%), 5 (7.0%), 10 (14.1%), 39 (54.9%), and 16 (22.5%) patients underwent PG, DG, segmental gastrectomy, local resection, and endoscopic submucosal dissection, respectively, in the SND group. There was no significant difference in postoperative complications between the SNM and SND groups (P = 0.781). Survival did not differ between the both groups (P = 0.856). The present results suggest that personalized surgery with SND provides technical safety and curability related with a favorable survival outcome in patients with EGC.

New evidence guiding extent of lymphadenectomy for esophagogastric junction tumor: Application of Ber-Ep4 Joint with CD44v6 staining on the detection of lower mediastinal lymph node micrometastasis and survival analysis

For Siewert type II adenocarcinoma of the esophagogastric junction (AEJ), the optimal surgical approach and extent of lymph nodes dissection remain controversial. Immunohistochemistry (IHC) has been reported to be available for identifying lymph node micrometastasis (LNMM) in patients with AEJ. This was a prospective case series of patients who underwent R0 resection and lower mediastinal lymphadenectomy from January 2010 to June 2015 in Fujian Medical University Union Hospital for Siewert type II AEJ. The outcomes were analyzed retrospectively. A total of 1325 lymph nodes were collected from 49 patients, grouped into 3 groups: lower mediastinal, paracardial, and abdominal. The former 2 groups were examined by monoclonal antibodies against Ber-Ep4 and CD44v6. The incidence of LNMM in mediastinal group was 37% (18/49) for Ber-Ep4 and 33% (16/49) for CD44v6. While in routine histological diagnosis, the number of patients with the positive lymph nodes was 7 (14%). When combining IHC with histopathology (HE) staining, the incidence of positive mediastinal lymph nodes was increased to 24%, with a total number of 37 lymph nodes from 28 patients (57%). Micrometastases indicated by Ber-Ep4 and CD44v6 were associated with the depth of tumor invasion (P = 0.020 and 0.037, respectively), histopathological nodal status (P = 0.024 and 0.01, respectively), and Lauren classification (P = 0.038 and, respectively). Expression of CD44v6 and Ber-Ep4 was positively correlated (r = 0.643, P < 0.001). The 3- and 5-year survival rates for all patients were 66% and 50%, respectively. The patients with LNMM had a lower 3-year survival rate of 51%, compared to 80% from no LNMM group; 5-year survival rate was also lower in LNMM group, which is 29% versus 68% (P = 0.006) in the no LNMM group. Patients with positive Ber-Ep4 cells had a lower survival, but not statistically significant (P = 0.058). CD44v6-positive group had a significantly reduced survival (P < 0.001). In patients group with negative lower mediastinal lymph nodes, patients without LNMM obtained a significant survival benefit (P = 0.021). Our study demonstrated that routine test for LNMM is necessary for patients with negative lymph nodes. As a positive prognostic factor, thorough lower mediastinal lymphadenectomy in an invasive approach should be considered when necessary. Ber-Ep4 and CD44v6 were shown to be great markers for detecting LNMM.

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.

Prognostic Impact of Para-Aortic Lymph Node Micrometastasis in Pancreatic Ductal Adenocarcinoma

BACKGROUND

It is still unclear whether micrometastasis of para-aortic lymph nodes (PALNs) in pancreatic ductal adenocarcinoma (PDAC) is tantamount to PALN metastasis detected by hematoxylin and eosin (HE) staining.

METHODS

A total of 242 patients with PDAC who underwent radical pancreatectomy with PALN dissection were eligible for this study. Micrometastasis in PALNs was evaluated by CAM 5.2 immunohistochemistry. The relationship between PALN status and overall survival (OS) was analyzed.

RESULTS

Of the 242 enrolled patients, 25 (10 %) had PALN metastasis detected by HE (PALN HE-positive), and 21 (9 %) had PALN micrometastasis not detected by HE but identified by CAM 5.2 immunohistochemistry. Univariate analysis revealed that patients with PALN micrometastasis (p = .004) and PALN HE positivity (p = .003) had a significantly shorter OS than those without PALN metastasis, whereas no significant difference was observed between the two former groups (p = .874). In multivariate analysis, lack of adjuvant chemotherapy (hazard ratio [HR] 2.43, p < .001), PALN micrometastasis (HR 1.89; p = .046), and PALN HE-positivity (HR 1.89, p = .023) were identified as independent risk factors for poor prognosis. Within a subset of 46 patients with PALN HE-positivity or micrometastasis, lack of adjuvant chemotherapy was independently associated with poor OS (HR 2.58. p = .029).

CONCLUSIONS

The prognosis of patients with PALN micrometastasis was extremely poor as well as HE-positive PALNs. However, postoperative adjuvant chemotherapy may contribute to improving the prognosis of PDAC patients with PALN metastasis.

A Risk Prediction Model Based on Lymph-Node Metastasis in Poorly Differentiated-Type Intramucosal Gastric Cancer

Background and Aim

Endoscopic submucosal dissection (ESD) for undifferentiated type early gastric cancer is regarded as an investigational treatment. Few studies have tried to identify the risk factors that predict lymph-node metastasis (LNM) in intramucosal poorly differentiated adenocarcinomas (PDC). This study was designed to develop a risk scoring system (RSS) for predicting LNM in intramucosal PDC.

Methods

From January 2002 to July 2015, patients diagnosed with mucosa-confined PDC, among those who underwent curative gastrectomy with lymph node dissection were reviewed. A risk model based on independent predicting factors of LNM was developed, and its performance was internally validated using a split sample approach.

Results

Overall, LNM was observed in 5.2% (61) of 1169 patients. Four risk factors [Female sex, tumor size ≥ 3.2 cm, muscularis mucosa (M3) invasion, and lymphatic-vascular involvement] were significantly associated with LNM, which were incorporated into the RSS. The area under the receiver operating characteristic curve for predicting LNM after internal validation was 0.69 [95% confidence interval (CI), 0.59–0.79]. A total score of 2 points corresponded to the optimal RSS threshold with a discrimination of 0.75 (95% CI 0.69–0.81). The LNM rates were 1.6% for low risk (<2 points) and 8.9% for high-risk (≥2 points) patients, with a negative predictive value of 98.6% (95% CI 0.98–1.00).

Conclusions

A RSS could be useful in clinical practice to determine which patients with intramucosal PDC have low risk of LNM.

Practical intraoperative pathologic evaluation of sentinel lymph nodes during sentinel node navigation surgery in gastric cancer patients - Proposal of the pathologic protocol for the upcoming SENORITA trial

Over the last decade, as the number of patients with early gastric cancer increased and the subsequent survival rate improved, there has been a consistent effort to verify the applicability of the sentinel node concept in gastric cancer in a bid to improve postoperative quality of life in these patients. During sentinel node navigation surgery in gastric cancer patients, intraoperative pathologic examination of the retrieved sentinel nodes plays a critical role in determining the extent of surgery, but the optimal method is still under debate. Currently, a multicenter, phase III clinical trial is underway to compare laparoscopic sentinel basin dissection with stomach preserving surgery and standard laparoscopic gastrectomy in terms of oncologic outcomes in patients with clinical stage T1N0 gastric cancer. Herein, the currently available intraoperative pathologic techniques are reviewed and their clinical significance and applicability are appraised based on the published literature. The proper pathologic examination of the sentinel lymph nodes in an upcoming clinical trial (SENORITA trial) is also proposed here based on this review.

Identifying Reproducible Molecular Biomarkers for Gastric Cancer Metastasis with the Aid of Recurrence Information

To precisely diagnose metastasis state is important for tailoring treatments for gastric cancer patients. However, the routinely employed radiological and pathologic tests for tumour metastasis have considerable high false negative rates, which may retard the identification of reproducible metastasis-related molecular biomarkers for gastric cancer. In this research, using three datasets, we firstly shwed that differentially expressed genes (DEGs) between metastatic tissue samples and non-metastatic tissue samples could hardly be reproducibly detected with a proper statistical control when the metastatic and non-metastatic samples were defined by TNM stage alone. Then, assuming that undetectable micrometastases are the prime cause for recurrence of early stage patients with curative resection, we reclassified all the “non-metastatic” samples as metastatic samples whenever the patients experienced tumour recurrence during follow-up after tumour resection. In this way, we were able to find distinct and reproducible DEGs between the reclassified metastatic and non-metastatic tissue samples and concordantly significant DNA methylation alterations distinguishing metastatic tissues and non-metastatic tissues of gastric cancer. Our analyses suggested that the follow-up recurrence information for patients should be employed in the research of tumour metastasis in order to decrease the confounding effects of false non-metastatic samples with undetected micrometastases.

Sentinel Lymph Node Navigation Surgery for Early Gastric Cancer: Is It a Safe Procedure in Countries with Non-Endemic Gastric Cancer Levels? A Preliminary Experience

Purpose

Early diagnosis of gastric cancer is still the exception in Western countries. In the East, as in Japan and Korea, this disease is an endemic disorder. More conservative surgical procedures are frequently performed in early gastric cancer cases in these countries where sentinel lymph node navigation surgery is becoming a safe option for some patients. This study aims to evaluate preliminary outcomes of patients with early gastric cancer who underwent sentinel node navigation surgeries in Brazil, a country with non-endemic gastric cancer levels.

Materials and Methods

From September 2008 to March 2014, 14 out of 205 gastric cancer patients underwent sentinel lymph node navigation surgeries, which were performed using intraoperative, endoscopic, and peritumoral injection of patent blue dye.

Results

Antrectomies with Billroth I gastroduodenostomies were performed in seven patients with distal tumors. The other seven patients underwent wedge resections. Sentinel basin resections were performed in four patients, and lymphadenectomies were extended to stations 7, 8, and 9 in the other 10. Two patients received false-negative results from sentinel node biopsies, and one of those patients had micrometastasis. There was one postoperative death from liver failure in a cirrhotic patient. Another cirrhotic patient died after two years without recurrence of gastric cancer, also from liver failure. All other patients were followed-up for 13 to 79 months with no evidence of recurrence.

Conclusions

Sentinel lymph node navigation surgery appears to be a safe procedure in a country with non-endemic levels of gastric cancer.

The clinical significance of para-aortic nodal dissection for advanced gastric cancer

BACKGROUND

Advanced gastric cancer with the risk of extensive nodal involvement has a poor prognosis even after radical surgery. We aimed to comprehensively review the clinical significance of extended radical dissection.

METHODS

Between 1990 and 1999, 232 patients underwent radical gastrectomy with D2 plus para-aortic lymph node dissection at the National Cancer Center Hospital in Tokyo. We analyzed the short-term surgical and long-term oncological outcomes of these operations.

RESULTS

Major complications occurred in 34 patients (14.7%). Median operation time was 325 min (range: 182-555) and median blood loss was 715 ml (range: 95-4457). There were 2 (0.9%) hospital deaths. Nodal involvement of the para-aortic area was seen in 33 patients (14.2%). The overall 5- and 10-year survival rates in patients with para-aortic node involvement were 21.2 and 15.2%, respectively. Multivariate analysis of patients with para-aortic node involvement revealed advanced age and metastasis in the interaorticocaval lymph nodes above the left renal vein to be independent risk factors impacting overall survival.

CONCLUSIONS

PAN dissection has limited applicability and effectiveness to the patients with advanced gastric cancer. Above all, advanced age and metastasis in the interaorticocaval lymph nodes above the left renal vein are significant poor prognostic factor even after radical resection.

Extent of lymph node dissection for adenocarcinoma of the stomach

BACKGROUND

The impact of lymphadenectomy extent on the survival of patients with primary resectable gastric carcinoma is debated.

OBJECTIVES

We aimed to systematically review and meta-analyze the evidence on the impact of the three main types of progressively more extended lymph node dissection (that is, D1, D2 and D3 lymphadenectomy) on the clinical outcome of patients with primary resectable carcinoma of the stomach. The primary objective was to assess the impact of lymphadenectomy extent on survival (overall survival [OS], disease specific survival [DSS] and disease free survival [DFS]). The secondary aim was to assess the impact of lymphadenectomy on post-operative mortality.

SEARCH METHODS

We searched CENTRAL, MEDLINE and EMBASE until 2001, including references from relevant articles and conference proceedings. We also contacted known researchers in the field. For the updated review, CENTRAL, MEDLINE and EMBASE were searched from 2001 to February 2015.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs) comparing the three main types of lymph node dissection (i.e., D1, D2 and D3 lymphadenectomy) in patients with primary non-metastatic resectable carcinoma of the stomach.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the included studies. Hazard ratios (HR) and relative risks (RR) along with their 95% confidence intervals (CI) were used to measure differences in survival and mortality rates between trial arms, respectively. Potential sources of between-study heterogeneity were investigated by means of subgroup and sensitivity analyses. The same two authors independently assessed the risk of bias of eligible studies according to the standards of the Cochrane Collaboration and the quality of the overall evidence based on the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) criteria.

MAIN RESULTS

Eight RCTs (enrolling 2515 patients) met the inclusion criteria. Three RCTs (all performed in Asian countries) compared D3 with D2 lymphadenectomy: data suggested no significant difference in OS between these two types of lymph node dissection (HR 0.99, 95% CI 0.81 to 1.21), with no significant difference in postoperative mortality (RR 1.67, 95% CI 0.41 to 6.73). Data for DFS were available only from one trial and for no trial were DSS data available. Five RCTs (n = 3 European; n = 2 Asian) compared D2 to D1 lymphadenectomy: OS (n = 5; HR 0.91, 95% CI 0.71 to 1.17) and DFS (n=3; HR 0.95, 95% CI 0.84 to 1.07) findings suggested no significant difference between these two types of lymph node dissection. In contrast, D2 lymphadenectomy was associated with a significantly better DSS compared to D1 lymphadenectomy (HR 0.81, 95% CI 0.71 to 0.92), the quality of the body of evidence being moderate; however, D2 lymphadenectomy was also associated with a higher postoperative mortality rate (RR 2.02, 95% CI 1.34 to 3.04).

AUTHORS' CONCLUSIONS

D2 lymphadenectomy can improve DSS in patients with resectable carcinoma of the stomach, although the increased incidence of postoperative mortality reduces its therapeutic benefit.

Occult Tumor Cells in Lymph Nodes of Patients with Gastric Cancer: A Systematic Review on Their Prevalence and Predictive Role

BACKGROUND AND AIMS

The presence of lymph node (LN) metastasis is a key prognostic factor for gastric adenocarcinoma. However, even among patients without LN metastasis (N0), recurrence may occur. In some of these cases, occult tumor cells (OTC) are thought to play an important role. We aimed to determine the prevalence of OTC and its clinical relevance.

METHODS

We conducted a systematic review of studies in English published until September 2013 that addressed OTC prevalence and/or its clinical relevance. The studies were retrieved from the MEDLINE database.

RESULTS

We included 42 studies. The most frequently used methods for detecting OTC were immunohistochemical examination (IHC) and/or polymerase chain reaction (PCR) with a wide range of markers. Using IHC for OTC detection, in patients and in LN, the prevalence varied from 9 to 88% and 0.4 to 42%, respectively. With PCR, it ranged from 17 to 46% in patients, and from 3 to 33% in LN. In the studies assessing the predictive role of OTC in gastric cancer recurrence (n=24), 8 studies found no statistical association, while 18 concluded that OTC presence was associated with poorer prognosis. However, only 6 studies presented a significantly different 5-year survival rate between patients with and without LN micrometastasis.

CONCLUSIONS

OTC seems to occur in gastric cancer patients with a variable prevalence, depending on the definition, methods and setting. The majority of the retrieved studies (75%) evaluating the predictive role of OTC conclude that its presence is associated with a worse prognosis.

Current status and scope of lymph node micrometastasis in gastric cancer

Recently, lymph node micrometastasis has been evaluated for its prognostic value in gastric cancer. Lymph node micrometastasis cannot be detected via a usual pathologic examination, but it can be detected by using some other techniques including immunohistochemistry and reverse transcription-polymerase chain reaction assay. With the development of such diagnostic techniques, the detection rate of lymph node micrometastasis is constantly increasing. Although the prognostic value of lymph node micrometastasis remains debatable, its clinical impact is apparently remarkable in both early and advanced gastric cancer. At present, studies on the prognostic value of lymph node micrometastasis are evolving to overcome its current limitations and extend the scope of its application.

Biopathologic features and clinical significance of micrometatasis in the lymph node of early gastric cancer

AIM: To evaluate the biopathologic features and clinical significance of nodal micrometastasis (MI) in early gastric cancer (EGC).

METHODS: Among 1022 EGC patients who underwent gastrectomy with lymphadenectomy of D1 + β or more from March 2001 to December 2005 at the Korean National Cancer Center, available nodal metastasis was found in 90 pT1N1 patients. Nodal metastasis was confirmed by immunohistochemistry (IHC) with cytokeratin and patients were classified into MI and macrometastasis (MA) groups based on the main tumor burden according to the 6^th International Union Against Cancer/American Joint Committee on Cancer staging system; the main tumor burden with a diameter of greater than 0.2 mm but no greater than 2 mm as MI, and greater than 2 mm as MA of the representative metastatic node. Proliferative and apoptotic activities of the primary tumor and the nodal metastasis were measured by IHC with Ki-67 and terminal deoxynucleotidyl transferase dUTP nick end labeling, respectively. Biopathologic and clinical features of the patients were analyzed and compared between MI and MA groups. Patients with recurrence were compared with those without recurrence to identify risk factors for recurrence.

RESULTS: Thirty-seven patients showed MI and the other 53 patients revealed MA in the lymph node; the incidence of patients with MI and MA was 41.1% and 58.9%. The main tumor burden was 0.9 and 4.6 mm in the representative metastatic node, respectively. Japanese N2 stations were more frequently involved in MA group (20.9%) than in MI group (10.3%) but the difference was not statistically different (P = 0.338). Proliferative and apoptotic activities of MI were decreased than those of MA (26.7% vs 40.5%, P = 0.004 and 1.0% vs 3.0%, P < 0.001, respectively). However, nodal MI in the current study showed a relatively high proliferative activity and an equivalent apoptotic activity compared to other cancers in the previously published studies. Recurrence was observed in 6 patients during the mean follow up period of 87.6 ± 26.2 mo. The recurrence was significantly associated with the presence of MA (P = 0.041) and lymphovascular invasion of the primary tumor (P = 0.032).

CONCLUSION: Lymphadenectomy of D1 + β or more might be necessary in patients with MI in sentinel node to prevent recurrence by clearing MI involving Japanese N2 station.

New approaches to gastric cancer staging: Beyond endoscopic ultrasound, computed tomography and positron emission tomography

Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and ¹⁸F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years.

Perspectives on new biomarkers in gastric cancer: Diagnostic and prognostic applications

Gastric cancer is considered one of the most deadly tumors worldwide. Even with the decline in its incidence, the mortality rate of this disease has remained high, mainly due to its late diagnosis and to the lack of precise prognostic markers. The main purpose of this review is to present genetic, epigenetic and proteomic molecular markers that may be used in a diagnostic and prognostic manner and to discuss the pros and cons of each type of marker for improving clinical practice. In this sense, we observed that the use of genetic markers, especially mutations and polymorphisms, should be carefully considered, as they are strongly affected by ethnicity. Proteomic-based markers show promise, but the higher costs of the associated techniques continue to make this approach expensive for routine use. Alternatively, epigenetic markers appear to be very promising, as they can be detected in bodily fluids as well as tissues. However, such markers must be used carefully because epigenetic changes may occur due to environmental factors and aging. Despite the advances in technology and its access, to date, there are few defined biomarkers of prognostic and diagnostic use for gastric tumors. Therefore, the use of a panel of several approaches (genetic, epigenetic and proteomic) should be considered the best alternative for clinical practice.

Endoscopic Resection for Early Gastric Cancer beyond Absolute Indication with Emphasis on Controversial Issues

Endoscopic resection is the established treatment for early gastric cancer in selected patients with negligible risk of lymph node metastasis ('absolute indication'). Based on clinical observations and large pathological databases, expanding indications for endoscopic resection beyond absolute indication has been tried in Japan and Korea. However, controversies exist regarding the safety of treating early gastric cancer beyond absolute indication in terms of pathological evaluation of the resected specimen, definition of expanded indication, discrepancy between pre-endoscopic resection and post-endoscopic resection diagnoses of gastric neoplasm, and the best strategy for cases with non-curative resection. In this brief review, current evidence and clinical experience regarding issues of endoscopic resection beyond absolute indication will be summarized.

Digestive cancer surgery in the era of sentinel node and epithelial-mesenchymal transition

Lymph node involvement is one of the most important prognostic indicators of carcinoma of the digestive tract. Although the therapeutic impact of lymphadenectomy has not been proven and the number of retrieved nodes cannot be considered a measure of successful cancer surgery, an adequate lymph node count should be guaranteed to accurately assess the N-stage through the number of involved nodes, lymph node ratio, number of negative nodes, ratio of negative to positive nodes, and log odds, i.e., the log of the ratio between the number of positive lymph nodes and the number of negative lymph nodes in digestive carcinomas. As lymphadenectomy is not without complications, sentinel node mapping has been used as the rational procedure to select patients with early digestive carcinoma in whom nodal dissection may be omitted or a more limited nodal dissection may be preferred. However, due to anatomical and technical issues, sentinel node mapping and nodal basin dissection are not yet the standard of care in early digestive cancer. Moreover, in light of the biological, prognostic and therapeutic impact of tumor budding and tumor deposits, two epithelial-mesenchymal transition-related phenomena that are involved in tumor progression, the role of staging and surgical procedures in digestive carcinomas could be redefined.

Negative node count improvement prognostic prediction of the seventh edition of the TNM classification for gastric cancer

OBJECTIVE

To demonstrate that the seventh edition of the tumor-node-metastasis (TNM) classification for gastric cancer (GC) should be updated with the number of negative lymph nodes for the improvement of its prognostic prediction accuracy.

METHODS

Clinicopathological data of 769 GC patients who underwent curative gastrectomy with lymphadenectomy between 1997 and 2006 were retrospectively analyzed to demonstrate the superiority of prognostic efficiency of the seventh edition of the TNM classification, which can be improved by combining the number of negative lymph nodes.

RESULTS

With the Cox regression multivariate analysis, the seventh edition of the TNM classification, the number of negative nodes, the type of gastrectomy, and the depth of tumor invasion (T stage) were identified as independent factors for predicting the overall survival of GC patients. Furthermore, we confirmed that the T stage-N stage-number of negative lymph nodes-metastasis (TNnM) classification is the most appropriate prognostic predictor of GC patients by using case-control matched fashion and multinominal logistic regression. Finally, we were able to clarify that TNnM classification may provide more precise survival differences among the different TNM sub-stages of GC by using the measure of agreement (Kappa coefficient), the McNemar value, the Akaike information criterion, and the Bayesian Information Criterion compared with the seventh edition of the TNM classification.

CONCLUSION

The number of negative nodes, as an important prognostic predictor of GC, can improve the prognostic prediction efficiency of the seventh edition of the TNM classification for GC, which should be recommended for conventional clinical applications.

Oncologic safety of pylorus-preserving gastrectomy in the aspect of micrometastasis in lymph nodes at stations 5 and 6

BACKGROUND

Pylorus-preserving gastrectomy (PPG) is a function-preserving gastrectomy for early gastric cancers (EGCs) that are preoperatively assessed as pN0 tumors and located in the middle portion of the stomach. In PPG, dissection of the lymph nodes at stations 5 and 6 is frequently incomplete, and this may be worrisome in terms of oncologic safety.

METHODS

We examined lymph nodes collected from stations 5 and 6 from 196 patients who had undergone conventional distal gastrectomy (CDG) for EGC located in the middle portion of the stomach and from 24 patients who had undergone PPG.

RESULTS

The average number of lymph nodes collected at station 5 was significantly lower with PPG than with CDG (0.08 vs. 1.32, respectively; P = 0.008). However, such a difference was not noted for station 6 nodes. The rate of macrometastasis was very low in all station 5 nodes (1 of 220, 0.45%) and station 6 nodes (1 of 220, 0.45%). Immunohistochemical analysis of cytokeratin in 109 cases of the CDG group and 21 cases of the PPG group showed that micrometastasis of single isolated tumor cell type was observed in only one station 6 lymph node of a patient who was initially diagnosed with pN0 EGC. There were no cases of micrometastasis in station 5 nodes.

CONCLUSIONS

The possibility of micrometastasis to station 5 and/or 6 lymph nodes may be negligible for EGC located in the middle portion of the stomach, and PPG thus might be the oncologically safe procedure when considering micrometastasis in remaining nodes in vivo at stations 5 and 6.

The prognostic impact of occult lymph node metastasis in node-negative gastric cancer: a systematic review and meta-analysis

PURPOSE

To conduct a meta-analysis to clarify whether occult lymph node metastasis (OLNM), which is identified by molecular detection techniques but is not detected by routine histological examination within regional lymph nodes, represents a prognostic factor for patients with node-negative gastric cancer.

METHODS

PubMed, Embase, and the Cochrane Library were searched from their inception to November 2012. The published studies that investigated the association between OLNM and the prognosis of patients with node-negative gastric cancer were included. We extracted hazard ratios (HRs) and associated standard errors from the identified studies and performed random-effects model meta-analyses on overall survival and disease-specific survival. Subgroup analyses were also conducted.

RESULTS

A total of 14 eligible studies that included 1,478 patients were identified. Meta-analyses revealed that OLNM was associated with poor overall survival [HR 2.72; 95% confidence interval (CI) 1.61-4.60], and disease-specific survival (HR 2.91; 95% CI 1.25-6.79). Subgroup analyses suggested that OLNM was associated with poor survival in early gastric cancer (HR 3.57; 95% CI 1.23-10.33). However, subgroup analyses of studies that exclusively enrolled patients with D2 lymph node dissection demonstrated that OLNM did not have an influence on the prognosis (HR 1.97; 95% CI 0.82-4.70).

CONCLUSIONS

OLNM correlates with poor prognosis for patients with node-negative gastric cancer, and D2 lymph node dissection could eliminate this correlation. For OLNM-positive patients with node-negative gastric cancer, D2 lymph node dissection is necessary.