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

PET/CT for Predicting Occult Lymph Node Metastasis in Gastric Cancer

A portion of gastric cancer patients with negative lymph node metastasis at an early stage eventually die from tumor recurrence or advanced metastasis. Occult lymph node metastasis (OLNM] is a potential risk factor for the recurrence and metastasis in these patients, and it is highly important for clinical prognosis. Positron emission tomography (PET)/computed tomography (CT) is used to assess lymph node metastasis in gastric cancer due to its advantages in anatomical and functional imaging and non-invasive nature. Among the major metabolic parameters of PET, the maximum standardized uptake value (SUVmax) is commonly used for examining lymph node status. However, SUVmax is susceptible to interference by a variety of factors. In recent years, the exploration of new PET metabolic parameters, new PET imaging agents and radiomics, has become an active research topic. This paper aims to explore the feasibility and predict the effectiveness of using PET/CT to detect OLNM. The current landscape and future trends of primary metabolic parameters and new imaging agents of PET are reviewed. For gastric cancer patients, the possibility to detect OLNM non-invasively will help guide surgeons to choose the appropriate lymph node dissection area, thereby reducing unnecessary dissections and providing more reasonable, personalized and comprehensive treatments.

CDX-1/CDX-2 Expression Is a Favorable Prognostic Factor in Epstein-Barr Virus-Negative, Mismatch Repair-Proficient Advanced Gastric Cancers

Background/Aims

Caudal type homeobox (CDX)-1 and -2 are reportedly involved in the development and progression of gastric cancer (GC). Although there are several reports on the prognostic significance of CDX-2 expression in GC, it remains controversial. In this study, we sought to validate the prognostic value of CDX-1 and -2 expression according to the histologic and molecular subtypes of GC.

Methods

In total, 1,158 cases of advanced GC were investigated using immunohistochemical staining and tissue microarrays for CDX-1 and -2 expression, and survival analysis was performed according to different histological and molecular subtypes.

Results

Of the 915 GCs with CDX-1 expression, 163 (17.8%) were Epstein-Barr virus (EBV)-positive or mismatch repair deficient (MMR-d), and the remaining 752 (82.2%) were EBV-negative or MMR-proficient (MMR-p). Of the 1,008 GCs with CDX-2 expression, 177 (17.5%) were EBV-positive or MMR-d, and the remaining 831 (82.5%) were EBV-negative or MMR-p. In the EBV-positive and MMR-d groups, CDX expression had no relationship with patient outcomes. In the EBV-negative and MMR-p groups, 404 (53.7%) and 523 (62.9%) samples were positive for CDX-1 and CDX-2 expression, respectively. Survival analysis demonstrated that CDX-1 and CDX-2 expression in all patients was correlated with favorable outcomes in terms of overall survival (multivariate analysis; p=0.018 and p=0.028, respectively). In the subgroup analysis, CDX-1 expression and CDX-2 expression were associated with favorable outcomes in EBV-negative and MMR-p intestinal (p=0.015 and p=0.010), and mixed and diffuse-type (p=0.019 and p=0.042) GCs, respectively.

Conclusions

The expression of CDX-1 and CDX-2 is a favorable prognostic factor in EBV-negative, MMR-p advanced GC. (Gut Liver 2021;15-704)

Survival Trends of Patients With Surgically Resected Gastric Cardia Cancer From 1988 to 2015: A Population-based Study in the United States

BACKGROUND

The incidence of gastric cardia cancer (GCC) patients has been increasing, while the survival trends of GCC patients over time remains unclear. Thus, the aim of our study was to determine the survival trends of GCC patients over time using a population-based data in the United States.

METHODS

A total of 9044 surgically resected GCC patients during 1988 to 2015 from the Surveillance, Epidemiology, and End Results (SEER) database were identified. The survival probabilities were calculated by Kaplan-Meier method and the different survival probabilities between groups were examined by log-rank test.

RESULTS

The median overall survival time was 27 (interquartile range, 12 to 99) months, and the median disease-specific survival time was 32 (interquartile range, 13 to 320) months for GCC patients. There was a statistically significant increase in median overall survival time (17 to 46 mo; P<0.001) and disease-specific survival time (19 to 67 mo; P<0.001) from 1988 to 1997 to 2008 to 2015. More GCC patients were diagnosed at an early stage in recent years. Meanwhile, adequate lymph nodes examined (eLNs) were obtained in more GCC patients during surgery. Also, the proportion of GCC patients who received chemoradiotherapy increased significantly. Moreover, early diagnosis, adequate eLNs, and chemoradiotherapy were associated with mortality.

CONCLUSIONS

The survival rates of surgically resected GCC patients had a significant improvement from 1988 to 1997 to 2008 to 2015 in the United States, which might relate to the early discovery of GCC, greater utilization of adequate eLNs, and chemoradiotherapy.

Lymph Node Yield Following Packet Submission After Isolation By Surgeon During Gastrectomy

Purpose

To compare the lymph node yields of lymph node packet submission (PS), packet submission after isolation by surgeons (PSI), and en bloc lymph node submission (EBS) after gastrectomy.

Methods

We conducted a prospective study including 118 gastric cancer patients who underwent gastrectomy between June 2016 and August 2016. We also retrospectively reviewed 607 patients who underwent gastrectomy from May 2015 to May 2016. Following gastrectomy, lymph node specimens were either submitted en bloc (EBS group), divided into packets with accompanying adipose tissue according to the lymph node stations (PS group), or isolated individually based on the surgeon’s visualization and palpation before submission to the Pathology Department (PSI group).

Results

The average lymph node yield was significantly higher in the PSI compared with the PS group in the prospective study (46.5±19.4 vs 31.8±11.1), and significantly higher in the PS compared with the EBS group in the retrospective study (31.5±12.6 vs 23.9±8.9) (both P<0.001). There was no significant difference in positive lymph node yields in either of these comparisons (prospective study, P=0.581; retrospective study, P=0.489). The survival curve indicated no significant difference between the PS and PSI groups (log rank P=0.957); however, these three groups share different lymph node ratio (LNR).

Conclusion

PSI could yield more lymph nodes than PS or EBS with a lower LNR at pathological examination. However, the difference in lymph nodes harvested had no impact on survival, which may need further investigation.

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.

Implications of clinical research on adjuvant chemotherapy for gastric cancer: Where to go next?

Postoperative adjuvant chemotherapy (ACT) confers superior gastric cancer (GC) survival in the Eastern cohort. However, is the current standard of ACT already excessive, or is it still necessary to increase its intensity for specific subgroups? Tailored ACT strategies for GC depend on gradual exploration by clinical trials in selected patients. Thus, understanding the implications of previous and current research can help us respond wisely and design effective, rational trials, save medical resources and make better decisions in clinical practice. After reviewing and analyzing studies on ACT for GC patients undergoing curative resection, we found that research strategies for conducting “addition” ACT for specific stages of the disease have achieved great progress in making ACT more tailored and personalized in consideration of pathology stages. Furthermore, trials indicate that “addition” ACT strategies for GC patient subgroups based on histological characteristics might be helpful to move toward a more specific tailored and personalized management approach. Designing ACT research focused on different node statuses should also be conducted according to the biological specificity of lymph node (LN) metastasis. Therefore, future trials designed to determine tailored treatment based on histological and biological characteristics for specific subgroups are urgently needed and conducted as the theme of the 2019 American Society of Clinical Oncology (ASCO): Caring for Every Patient, Learning from Every Patient.

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.

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.

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.

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.

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.

Gastric carcinoma: stage migration by immunohistochemically detected lymph node micrometastases

BACKGROUND

Immunohistochemically detected micrometastases of the regional lymph nodes in previously pN0-classified gastric cancer have been incorporated in the TNM staging system. This study aims to determine the incidence of such micrometastases in gastric carcinoma and to investigate their impact on stage grouping and prognosis.

METHODS

Ninety-five patients with gastric carcinoma classified as pN0 by conventional histological examination were enrolled. All patients underwent gastric resection with regional lymphadenectomy between 2006 and 2010. A total of 2018 lymph nodes was obtained (median, 20 Lymph nodes) and immunohistostained with anti-pan cytokeratin antibody (KL1).

RESULTS

Micrometastases were detected in regional lymph nodes by immunohistostaining in 16 out of all 95 patients. Fourteen patients were upstaged by micrometastasis-positive regional lymph nodes. Three patients demonstrated lymph nodes with isolated tumor cells alone. A significantly higher incidence of micrometastases was observed in patients with diffuse histologic type (p = 0.007) and total gastrectomy (p = 0.007). When isolated tumor cells were also regarded as lymph node involvement, the recurrence rate was significantly higher for node-positive than for node-negative patients and for those younger than 70 years (33.3 and 6.7 %, respectively; p = 0.026; n = 39). Overall survival analysis revealed no significant difference between micrometastasis-positive and micrometastasis-negative patients.

CONCLUSION

Immunohistostaining of regional lymph nodes in node-negative gastric carcinoma patients leads to an increased detection of micrometastases with significant implications for the staging system. Although no impact on survival time was shown, the higher recurrence rate for node-positive patients younger than 70 years indicates a prognostic value of immunohistochemically detectable micrometastases.

Gastric cancer patients less than 50 years of age exhibit significant downregulation of E-cadherin and CDX2 compared to older reference populations

PURPOSE

There is an increasing need to identify molecular markers, which can be used to prognosticate patient populations in gastric cancer. Whereas a significant number have been identified, very few have been characterized in the context of their ability to discriminate between young and old age groups in which a survival difference clearly exists.

MATERIAL/METHODS

In this study, using immunohistochemistry, we evaluated three markers with proven involvement in gastric cancer. The p53 tumor suppressor, the cell adhesion glycoprotein epithelial cadherin (CDH1) and the caudal-related homeobox transcription factor (CDX2) all of these have important roles in the aetiopathogenesis and/or progression of gastric cancer.

RESULTS

After adjustments for TNM stage, tumor grade, histopathological characteristics (Lauren classification), we found significant differences in the expression of these proteins, particularly E-cadherin and CDX2 between young and elderly patients. However, these differences did not amount to a significant difference in survival.

CONCLUSIONS

This study demonstrates that the protein expression of p53, CDH1 and CDX2 significantly discriminates young patients with gastric cancer who have a better prognostic outlook from older patients, but this difference in expression does not contribute to a survival benefit.

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.

Prognostic significance of Cdx2 immunohistochemical expression in gastric cancer: a meta-analysis of published literatures

Cdx2 is a homeobox domain-containing transcription factor that is important in the development and differentiation of the intestinal cells, and served as a potential biomarker of tumor progression in early intestinal-type gastric cancer. However, its prognostic value and significance in gastric cancer remain controversial. A meta-analysis based on published studies was performed to obtain an accurate evaluation of the association between the presence of Cdx2-positive in clinical samples and clinical outcome. A total of 13 eligible retrospective cohort studies with 1513 patients were included. Cdx2-positive cases were significantly associated with higher male-to-female ratio (RR=1.27, 95% CI: 1.17-1.38, P<0.00001 fixed-effect), lower (I+II) clinical stage (RR=1.63, 95% CI: 1.42-1.87, P<0.00001 fixed-effect), better histologic differentiation (RR=1.54, 95% CI: 1.34-1.76, P<0.00001 fixed-effect), and lower rate of vascular invasion (RR=1.23, 95% CI: 1.08-1.41, P=0.002 fixed-effect) and lymph node metastasis (RR=1.52, 95% CI: 1.33-1.73, P<0.00001 fixed-effect), as well as higher 5-year survival rate (HR=2.22, 95% CI: 1.78-2.75, P<0.00001 fixed-effect). However, the presence of Cdx2 was not associated with tumor size. In summary, Cdx2 is a prognostic factor in gastric cancer, which acts as a marker of good outcome in patients with gastric cancer. Further clinical studies are needed to confirm the role of Cdx2 in clinical practice.