Prognostic significance of immunohistochemical micrometastases in node negative gastric cancer patients

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

INTRODUCTION

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

AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Colorectal Cancer: What has Changed in Diagnosis and Treatment over the Last 50 Years?

Aims and background

This overview focuses on what has changed in the diagnosis and treatment of colorectal cancer over the last 50 years.

Methods

The most important international registers (SEER, European and Italian) as well as the literature have been consulted. Furthermore, many prognostic factors are analyzed with the aim to understand the reasons why 5-year survival has improved over the last two decades.

Results

Since the biologic characteristics of the tumor cannot be changed, improved survival must be supported by concomitant multiple factors, such as earlier diagnosis (as given by a more informed educational behavior and the advent of screening) as well as the wide use of colonoscopy and the technical improvement of surgical and medical treatment. However, it seems that the greatest improvement in survival is limited to 5-year controls, whereas long-term survival does not appear to show any significant improvement.

Conclusions

We can hypothesize that our efforts have just delayed the inevitable end: death. Nevertheless, further research should be done to confirm this hypothesis, perhaps in the field of molecular biology, which may also be the right approach to understanding the biologic aggressiveness of each tumor.

[Micrometastasis in Gastric Cancer]

Although the incidence and mortality rate of gastric cancer have been steadily declining, gastric cancer is still the fourth most common cancer in the world and more than 50% of cases occur in Eastern Asia. In Korea, gastric cancer is the second most common cancer and third cause of cancer related death. The standard surgical procedure for resectable advanced gastric cancer is D2 lymphadenectomy with radical gastrectomy. Even though R0 resection was completed, recurrence is relatively common, and contributes to the limited survival of the patients in gastric cancer. As a clinically relevant factor for detection of the recurrence, the presence of isolating tumor cells has been introduced and it is so called as 'micrometastasis'. Numerous immunohistochemistry and molecular studies have shown that micrometastasis can be demonstrated not only in lymph nodes but also in such body compartments as the bone marrow, peritoneal cavity and blood. Herein, we review the current knowledge and evidence of the prognostic significance of micrometastasis in peritoneal, lymph node, bone marrow. Also, we discuss the current state of research on the circulating tumor cell in peripheral blood.

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.

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.

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.

Should lymph node micrometastasis be considered in node staging for gastric cancer?: the significance of lymph node micrometastasis in gastric cancer

BACKGROUND

In TNM staging system, lymph node staging is based on the number of metastatic lymph nodes in gastric cancer and micrometastasis is not considered. Several reports proposed the importance of lymph node micrometastasis as the causative factor for recurrence and poor survival, but it remains controversial among researchers.

METHODS

A total of 482 gastric cancer patients who underwent curative resection from 2004 to 2010 at Korea University Medical Center Ansan Hospital, South Korea were prospectively enrolled. For detecting lymph node micrometastasis, immunohistochemical staining with anti-cytokeratin antibody (CAM 5.2) was performed on negative lymph nodes by hematoxylin-eosin (H-E) staining. Survival differences were compared between conventional node staging and new node staging that took micrometastasis into consideration. Also, the prognostic value of lymph node micrometastasis was investigated in multivariate analysis.

RESULTS

A total of 156 patients (32.4%) showed lymph node micrometastasis. Overall, the micrometastatic group had more advanced tumor and lymph node stage, lymphovascular cancer cell invasion, a higher rate of recurrence, and poor survival. Furthermore, when the cumulative numbers of macro- and micrometastatic lymph nodes were calculated together, the discriminative power of survival difference between each node stage became more stratified. Also, multivariate analysis using Cox's proportional hazards model demonstrated perineural invasion, pathologic T stage, dissected lymph nodes, macro- and micrometastatic lymph nodes are independent prognostic factors.

CONCLUSIONS

Lymph node micrometastasis was clinically significant as a risk factor for recurrent gastric cancer. Lymph node micrometastasis should be considered when estimating TNM stage for determining prognosis and the best treatment strategy.

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.

Biological and molecular aspects of lymph node metastasis in gastro-intestinal cancer

Recently, the existence of lymph node micrometastasis, including isolated tumor cells, has been the focus of the development of molecular diagnostic tools for lymph node metastasis in various malignant neoplasms, including those of the GI tract. In this review, we summarize recent molecular biological studies that might provide two reasons to explain the survival of single isolated cancer cells in lymph nodes. One is the specific characteristics of cancer cells, which can exist under severe circumstances, along with recent technological innovations to obtain expression profiles and sequencing from a single cell. The other is microenvironmental factors that support the formation of micrometastasis even in small numbers of cancer cells. The expression profile of whole transcriptome sequencing, genomic sequencing and epigenetic sequencing of a single cancer cell with tumorigenic properties in lymph node metastases should be disclosed in the near future.

Lymph node micrometastasis in gastrointestinal tract cancer--a clinical aspect

Lymph node micrometastasis (LNM) can now be detected thanks to the development of various biological methods such as immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Although several reports have examined LNM in various carcinomas, including gastrointestinal (GI) cancer, the clinical significance of LNM remains controversial. Clinically, the presence of LNM is particularly important in patients without nodal metastasis on routine histological examination (pN0), because patients with pN0 but with LNM already in fact have metastatic potential. However, at present, several technical obstacles are impeding the detection of LNM using methods such as IHC or RT-PCR. Accurate evaluation should be carried out using the same antibody or primer and the same technique in a large number of patients. The clinical importance of the difference between LNM and isolated tumor cells (≤0.2 mm in diameter) will also be gradually clarified. It is important that the results of basic studies on LNM are prospectively introduced into the clinical field. Rapid diagnosis of LNM using IHC and RT-PCR during surgery would be clinically useful. Currently, minimally invasive treatments such as endoscopic submucosal dissection and laparoscopic surgery with individualized lymphadenectomy are increasingly being performed. Accurate diagnosis of LNM would clarify issues of curability and safety when performing such treatments. In the near future, individualized lymphadenectomy will develop based on the establishment of rapid, accurate diagnosis of LNM.

Intraoperative diagnosis of lymph node metastasis by transcription-reverse transcription concerted reaction assay in gastric cancer

BACKGROUND

Increasing evidence has been accumulated to substantiate the clinical usefulness of quantitative evaluation of gene expression. This study was undertaken to assess diagnosis of metastasis in dissected lymph nodes through quantitative evaluation of the expression of carcinoembryonic antigen mRNA (CEA mRNA) by a rapid, simple transcription-reverse transcription concerted reaction (TRC) assay using dissected lymph node washings.

METHODS

A total of 110 dissected lymph nodes from 40 patients undergoing surgery for gastric cancer were studied. Each dissected lymph node was cut crosswise and washed with physiological saline. The washings were assayed for CEA mRNA and the assay results were assessed in comparison with the pathological diagnosis [hematoxylin and eosin (H&E) staining]. All lymph nodes were also subjected to immunostaining for cytokeratin (CK staining) and assessed comparatively.

RESULTS

By H&E staining, 29 lymph nodes were found to be positive and 81 to be negative for metastasis. By TRC assay, 38 lymph nodes were found to be positive and 72 to be negative. According to the results of CK staining, there were 37 metastasis-positive lymph nodes and 73 negative nodes. The sensitivity and specificity of H&E staining relative to those of CK staining were 78.4 and 100 %, respectively, while the sensitivity and specificity of TRC assay relative to those of CK staining were 91.9 and 94.5 %, respectively.

CONCLUSIONS

The TRC assay method using lymph node washings is a rapid, simple genetic diagnosis with greater sensitivity than conventional diagnosis by H&E staining of permanent specimens, and enables conservation of lymph nodes in toto as permanent specimens. This TRC method would enable rapid diagnosis even in town hospitals where no pathologist is ordinarily stationed, and is considered to contribute to the clinical application of the sentinel node theory of gastric cancer treatment.

Comparison of immunohistology using pan-CK and EMA in the diagnosis of lymph node metastasis of gastric cancer, particularly micrometastasis and isolated tumor cells

The aim of this study was to identify a suitable method for detecting lymph node metastasis of gastric cancer (GCA) by hematoxylin and eosin (HE) and immunohistochemical (IHC) staining. We investigated lymph node metastasis using pan-cytokeratin (CK) and epithelial membrane antigen (EMA) IHC staining in a total of 1,422 lymph nodes from 100 patients who underwent radical gastrectomy between 2007 and 2009. Of 700 intestinal and 722 diffuse type GCA lymph nodes, the metastasis rates were significantly different when using conventional HE staining only or HE supplemented with IHC (P<0.01). The metastasis rate of the intestinal type was 31.71% using HE staining, 35.71% with HE and pan-CK, 35.57% with HE and EMA and 35.71% with combination examinations of all three. The false-positive rate was zero with pan-CK, 12.67% with EMA and 18.57% with all three. The metastasis rate of the diffuse type was 27.70% using HE staining, 36.01% with HE and pan-CK, 35.04% with HE and EMA and 36.01% with all three. The false-positive rate was zero with pan-CK, 7.58% with EMA and 11.86% with all three. For both types, the true-positive and -negative rates of pan-CK were higher than those of EMA. IHC staining is unnecessary if lymph node metastasis is detected in HE staining. If HE staining does not reveal metastasis, pan-CK staining should be performed for further diagnosis.

Clinical significance of lymph node micrometastasis in gastric cancer

Recently, the existence of lymph node micrometastasis (LNM), including isolated tumor cells, has been focused on during the development of molecular diagnostic tools for lymph node metastasis in various malignant neoplasms. In particular, immunohistochemistry and reverse transcription-polymerase chain reaction have been reported to be available for the detection of LNM in gastric cancer. However, at present, the clinical significance of LNM remains unclear in patients with gastric cancer. Therefore, we cannot strategically make light of this issue in clinical management. Currently, minimally invasive treatments, such as endoscopic submucosal dissection and laparoscopic surgery with personalized lymphadenectomy, are widely performed in consideration of postsurgical quality of life (QOL). However, it is important to maintain the balance between QOL and curability when selecting surgical treatments for patients with gastric cancer. If minimally invasive surgery based on LNM status was established for patients with early gastric cancer, it could be performed safely. We reviewed the clinical significance of LNM as an important strategic target in patients with gastric cancer.

Do we have enough evidence for expanding the indications of ESD for EGC?

Endoscopic submucosal dissection (ESD) is the most advanced and representative technique in the field of therapeutic endoscopy and has been used for the treatment of gastrointestinal neoplasms, including early gastric cancer. The major difference and advantage of ESD compared to existing endoscopic resection techniques, such as endoscopic mucosal resection (EMR) and polypectomy, are the width and depth of the resection. Newly developed cutting devices, distal attachable endoscopic accessories, and an advanced electrosurgical unit have helped to overcome the limitations of therapeutic endoscopy in terms of lesion size, location, presence of fibrotic scarring, and accompanying ulcers. As a result, the indications for ESD have been expanded from the classical indication for EMR and polypectomy, and there is now support for a further expansion of ESD indications. At present, the most critical factor to consider in the decision of whether to perform ESD is the probability of unexpected lymph node metastasis. The guidelines for ESD are continually being updated and debated. In this review, we discuss the strengths and weaknesses of the expanded guidelines, based on evidence found in the literature.

A multicentric Western analysis of prognostic factors in advanced, node-negative gastric cancer patients

BACKGROUND

The presence of lymph node metastasis is one of the most important prognostic factors in patients with gastric carcinoma. Node-negative patients have a better outcome, nevertheless a subgroup of them experience disease recurrence.

AIM

To analyze the clinicopathological characteristics of lymph node-negative advanced gastric carcinoma patients submitted to gastrectomy and D2 lymphadenectomy with a retrieved number of nodes greater than 15, after an actual follow-up of almost 5 years, and to evaluate outcome indicators.

STUDY DESIGN

The records of 301 patients who underwent curative gastrectomy for gastric carcinoma and were adequately staged as N0 between 1992 and 2002 were retrospectively analyzed from the prospectively collected database of 7 centers participating to the Italian Research Group for Gastric Cancer.

RESULTS

Disease-specific and disease-free survival after 3, 5, and 10 years were 90.4%, 86.1%, 75.9%, and 72.1%, 57.3%, 57.3%, respectively. Mortality was 1.7%. The factors associated with a better disease-free survival at univariate analysis were age <60, T2 tumors, distal location, intestinal histotype, and number of retrieved nodes >25; depth of infiltration and histotype were the only 2 independent predictors of 5-year recurrence-free survival at multivariate analysis.

CONCLUSION

These parameters must be considered to stratify node-negative gastric cancer patients for an adjuvant treatment and follow-up scheduling. Survival was similar to that previously reported by Eastern Centers. Lymphadenectomy is suggested to be effective, and retrieval of more than 25 nodes may be warranted.

Safety of extended endoscopic mucosal resection and endoscopic submucosal dissection following the Japanese Gastric Cancer Association treatment guidelines

BACKGROUND

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are widely performed. Indications for these procedures have been extended in Korea and Japan. The aim was to evaluate whether these extended indications are safe.

METHODS

All patients who had surgery for early gastric cancer at Seoul National University Bundang Hospital between May 2003 and December 2007 were identified from a prospective database. Lymph node status was examined in patients who met extended indications for EMR and had undergone surgical resection.

RESULTS

Of patients with mucosal cancers, 129 met extended indications for EMR or ESD and three (2.3 per cent) had lymph node metastasis. Of the 52 submucosal cancers meeting extended indications for EMR or ESD, two (4 per cent) had lymph node metastasis. Differentiated mucosal cancers without ulcer formation did not have lymph node metastasis, irrespective of size.

CONCLUSION

Extending the indications for EMR and ESD according to the Japanese Gastric Cancer Association guidelines carries an increased risk of lymph node metastasis. For cancers meeting these criteria, treatment by gastric resection with lymph node dissection should still be considered. A well differentiated mucosal cancer of any size without ulceration may be considered as an extended indication for EMR or ESD.

Factors affecting recurrence in node-negative advanced gastric cancer

BACKGROUND AND AIM

Prognostic factors of lymph node-negative gastric adenocarcinoma after curative resection have been discussed. Recurrent pattern of advanced lymph node-negative gastric cancer after curative resection has rarely been described.

METHODS

Recurrent sites and correlated clinicopathological factors of 372 patients with lymph node-negative advanced gastric adenocarcinoma that underwent R0 resection from 1988 to 2005 were analyzed.

RESULTS

Recurrence was noted in 51 (13.7%) patients. Recurrent rates according to site of recurrence were 26 peritoneal seeding (51.0%), 26 locoregional (51.0%), 17 hematogenous (33.3%), and 4 lymph node metastasis (7.8%). Clinicopathological factors to predict peritoneal seeding were serosal exposure, lymphovascular invasion, Lauren's diffuse type differentiation and scirrhous stromal reaction. Serosal exposure, tumor size, microscopic infiltrating growth type predicts locoregional recurrence. Tumor had only lymphovascular invasion predict hematogenous spreading.

CONCLUSION

Node-negative advanced gastric cancer has more peritoneal seeding and locoregional recurrence. Aggressive cell behavior predicted the route of tumor cell spreading.

Prognostic significance of occult lymph node micrometastasis in gastric cancer: a histochemical and immunohistochemical study based on 1997 UICC TNM and 1998 JGCA classifications

BACKGROUND: Micrometastasis is a single or a cluster of malignant cells inside the lymph node that are not detected by routine histopathological sections. Micrometastasis is related to poorer prognosis in many gastric cancer studies the real significance of these cells is still controversial. AIM: To evaluate if lymph node micrometastasis is a significant independent prognostic factor and important risk factor for recurrence in gastric cancer. METHODS: A total of 1290 lymph nodes from 28 patients with gastric cancer, since 1998 until 2003, treated by radical resection (D2 and modified D3 lymphadenectomies) were studied. Three sections per lymph node were stained by Hematoxilin-Eosin, histochemical (AB-PAS) and immunohistochemical (AE1-AE3) techniques. Kaplan-Meier's survival curves and Log-rank/Cox tests were used in order to compares lymph node micrometastasis positivity, depth (pT) and location of tumor in gastric wall, histologic type, lymphatic, vascular and perineural invasion, lymph node status (pN) and stage. RESULTS: There were worse prognosis and recurrence in patients with positive lymph node micrometastasis related to vascular and perineural invasions, advanced lymph node status and advanced stages. CONCLUSION: Lymph node micrometastasis seems to be a significant independent prognostic factor and important risk factor for recurrence in gastric cancer, in a context of radical D2 lymphadenectomy

Lymph node micrometastasis in node negative early gastric cancer

AIMS

The clinical significance of lymph node micrometastasis for histologically node negative gastric cancer is not well documented. This study was to assess the incidence and to clarify the risk factors of lymph node micrometastasis in patients with node negative early gastric cancer (EGC).

METHODS

We investigated the lymph node micrometastasis with using an anticytokeratin immunohistochemical stain in 90 patients with node negative EGC who underwent curative resection between 1991 and 2000.

RESULTS

Among 3526 nodes from 90 patients, there were 17 cytokeratin immunohistochemical stain positive nodes from nine patients. The incidence of micrometastasis was higher in patients with lymphatic invasion (p=0.012), venous invasion (p=0.026) and larger tumor (p=0.003). The independent risk factors for lymph node micrometastasis were lymphatic invasion (p=0.004, RR=22.915, 95% CI = 2.709 ~ 193.828) and tumor size (p=0.029, RR=1.493, 95% CI = 1.042 ~ 2.138). Although there were 10 deaths during the follow-up period of mean 67.6 months (1 month ~ 147 months), there was no death from a cancer recurrence.

CONCLUSIONS

The incidence of lymph node micrometastasis in patients with node negative early gastric cancer was 10%, and the independent risk factors for micrometastasis were lymphatic invasion and tumor size.

Detection of micrometastases in sentinel node navigation surgery for gastric cancer

Although lymph node metastasis is one of the important prognostic factors for patients with gastric cancer, the clinical significance of micrometastasis remains controversial. In the 6th edition of the TMN classification, micrometastases were classified as micrometastasis (MM) and isolated tumor cells (ITC) according to its greatest dimension. The accurate diagnosis of micrometastases is required when considering less invasive surgery, especially in early stage of gastric cancer. Since generating useful information about micrometastases by conventional RT-PCR is time-consuming, this procedure is not useful for rapid diagnosis during surgery. Recently some new methods of genetic diagnosis have reduced the amount of time required to obtain information about micrometastases in lymph nodes to 30-40 min. Such methodology can be clinically applied during less invasive surgery. The sentinel node (SN) concept has recently been applied to gastric cancer and SN navigation surgery (SNNS) is ideal for reduction of lymphadenectomy in patients with early gastric cancer. However, we should think about some conditions to establish SN concept for gastric cancer: the particle size of radioisotope, relationship between metastatic area and RI uptake, and the diagnosis of micrometastases by various method such as histological examination, immunostaining and RT-PCR. Here, we described the current status of MM and ITC in the lymph nodes and the SN concept in gastric cancer.

The significances of lymph node micrometastasis and its correlation with E-cadherin expression in pT1-T3N0 gastric adenocarcinoma

BACKGROUND

Recently, micrometastasis (MM) in the lymph node in gastric cancer has been detected by cytokeratin immunostaining. However, clinical significance of MM and its relationship with reduced expression of E-cadherin in primary lesion have not been well studied.

METHODS

The 4,990 lymph nodes from 184 pT1~T3N0 patients from 1995 to 2000 at Korea University Hospital were immunostained with the anticytokeratin AE1/3 antibody for detection of micometastasis. The primary lesions were also immunostained for E-cadherin expression.

RESULTS

MM in the lymph node of gastric cancer was found in 131 (2.6%) of total dissected nodes, and 31 of 184 patients (16.8%) were shown to have MM. The MM was significantly correlated with the depth of invasion, tumor size, operation method, Lauren classification, lymphovascular invasion and loss of E-cadherin expression in primary tumor. On multivariate analysis, the independent risk factors for MM were the depth of invasion and loss of E-cadherin expression. The patients with MM had significantly lower 5-year overall and disease free survival rate than those without MM.

CONCLUSION

Lymph node MM in histologically node-negative gastric cancer was significantly correlated with poor 5-year survival rate. The determination of E-cadherin expression in primary gastric tumor may be useful in prediction of the MM.

Effect of lymph node micrometastases on prognosis of gastric carcinoma

AIM: To evaluate the relationship between lymph node micrometastases and prognosis of patients with gastric carcinoma and to evaluate the significance of the new assessment of nodal status in determining the pN categories in the 5th edition of the UICC TNM classification.

METHODS: A total of 850 lymph nodes from 30 patients with gastric carcinoma who underwent gastrectomy with lymphadenectomy were assessed by reverse transcription polymerase chain reaction assay in addition to histologic examination. Cytokeratin-20 gene marker was used in this assay.

RESULTS: Routine examination by HE staining confirmed metastasis in 233 lymph nodes from 20 patients. All these 233 lymph nodes were cytokeratin-20 positive. Moreover, lymph node micrometastases were detected in an additional 67 lymph nodes in 12 of these 20 patients. Lymph node micrometastases were also detected in 10 lymph nodes from 2 of 10 patients who had no obvious metastases identified by HE staining. Totally, lymph node micrometastases were identified by the reverse transcription polymerase chain reaction assay in 77 (12.5%) lymph nodes from 14 (46.7%) patients with gastric carcinoma. Of 27 patients who underwent curative resection, 7 (25.9%) were up-staged (fromIB stage to II stage in 1 patient, from IB stage to IIIA stage in 1 patient, from II stage to IIIA stage in 1 patient, from IIIA stage to IIIB stage in 1 patient, from IIIA stage to IV stage in 1 patient, from IIIB stage to IV stage in 2 patients). In a median follow-up of 32 (range 8-36) mo, Kaplan-Meier survival analysis showed significant improvements in median survival (22.86 ± 3.17 mo, 95% CI: 16.64-29.08 mo vs 18.00 ± 7.4 mo, 95% CI: 3.33-32.67 mo) of patients with negative lymph node micrometastases over patients with positive lymph node micrometastases (log-rank, P < 0.05).

CONCLUSION: Lymph node micrometastases have a significant impact on the current staging system of gastric carcinoma, and are significant risk factors for prognosis of patients with gastric carcinoma.

Sentinel node micrometastases have high proliferative potential in gastric cancer

BACKGROUND

The 6th edition of the TNM classification has recently defined "sentinel nodes (SN)," "micrometastasis," and "isolated tumor cells (ITC)." The present study examines the frequency and proliferative activity of such metastases with focus on the SNs of gastric cancer.

METHODS

We enrolled 133 patients with cT1-2 tumors (cT1: 104, cT2: 29) and mapped SNs. Lymph node metastases were examined by routine histology and by immunohistochemistry with anti-cytokeratin. We used the Ki-67 antibody to detect the primary tumor and lymph node metastases to evaluate proliferative activity.

RESULTS

The number of patients with SNs metastases and metastatic SNs was 19 and 52, respectively. The frequencies of macrometastasis, micrometastasis, and ITC were 48%, 25%, and 27%, respectively. Ki-67 expression in the tumor closely correlated with lymphatic invasion (P = 0.0001), venous invasion (P < 0.0001), and lymph node metastasis (P < 0.0001). Cells in 96% of macrometastases, 92% of micrometastases, and 29% of ITCs were Ki-67 positive.

CONCLUSIONS

We showed that micrometastasis and some ITCs in SNs had proliferative activity. We suggest that micrometastasis and ITCs should be removed, especially during SN navigation surgery, until their clinical significance is clarified.

Assessment of pelvic lymph node micrometastatic disease in stages IB and IIA of carcinoma of the uterine cervix

The objective of this study was to assess the frequency of micrometastatic disease (MID) in pelvic lymph nodes (PLNs) in carcinoma of the uterine cervix (CUC) and to determine the risk of recurrence. The PLNs from 289 patients with CUC (IB and IIA) were studied. Each PLN was assessed via immunohistochemistry using a single histologic section (AE1/AE3). Metastatic deposits were measured and the disease status was classified into three groups: 1) absence of metastatic disease (MOD); 2) MID, one or more metastatic PLN with only isolated tumor cells and/or micrometastases (up to 2 mm); and 3) macrometastatic disease (MAD), presence of one or more metastatic PLN with macrometastases (more than 2 mm). Eleven patients (3.8%) were classified as having MID and 37 (12.8%) as having MAD. The 5-year disease-free survival (DFS) rates for MOD, MAD, and MID were 88.7%, 80.4%, and 50.0%, respectively (P < 0.001). The Cox proportional hazards model showed that MID was an independent variable for recurrence when adjusted for MAD, depth of tumor invasion, severity of inflammatory reaction, and use of adjuvant radiotherapy. We conclude that the frequency of MID in PLN was low. However, patients with MID presented a high risk of recurrence and reduced DFS.

Assessment of lymph node micrometastasis in early gastric cancer in relation to sentinel nodes

BACKGROUND

The development of endoscopic resection and reduced surgical procedures has progressed in recent years. Lymph node micrometastases can be cited as one of the problems with reduced operations. In this study, we investigated clinicopathological findings and sentinel lymph nodes (SNs) for associations with micrometastases. We discuss the indications for endoscopic mucosal resection (EMR), reduced surgery, and sentinel node navigation surgery (SNNS) based on the results.

METHODS

Immunostaining with anti-cytokeratin antibodies was used as the method of exploring for micrometastases. Comparisons and assessments were made in regard to the presence or absence of micrometastases and various clinicopathological factors.

RESULTS

The relationship between the clinicopathological factors and micrometastases was investigated in 120 patients with pT1pN0 gastric cancer. Significant differences in depth of invasion (mucosal [m] versus submucosal [sm]) and histological type (differentiated versus undifferentiated) were observed in both univariate analysis and multivariate analysis. Micrometastases were observed in 32% of the sm cancers, and they were observed in group 2 lymph nodes (no. 7) in 8%. They tended to be more common in the undifferentiated type. The micrometastatic lymph nodes were restricted to blue nodes (BNs) and lymph nodes within the dye flow area of patent blue (used intraoperatively explore for SNs).

CONCLUSION

It is considered that the indications for current EMR and reduced surgery in early gastric cancer are valid from the standpoint of micrometastases. But if the SNNS that has been studied in recent years is introduced, the lymphatic basin dissection method seems valid only if the case is s-pN0 early cancer.

Prognostic Value of Cytokeratin-Positive Bone Marrow Cells of Gastric Cancer Patients

BACKGROUND

Epithelial cells in the bone marrow of patients with gastric cancer suggest tumor dissemination; however, their prognostic implications are controversial. We prospectively evaluated the correlation of bone marrow findings, recurrence rate, and disease-free survival after long-term follow-up.

METHODS

Bone marrow were aspirated from both iliac crests and stained with monoclonal cytokeratin (CK)-18 antibody in 209 patients before their initial operation. Patients were followed up for a median of 56 months.

RESULTS

Overall, 39 (19%) of 209 patients and 15 (14%) of 109 R0-resected patients had CK-positive cells. CK-positive patients had more local, regional, and distant recurrence than CK-negative patients (P < .05). We found a significantly shorter disease-free survival (P < .05) in the patients with >2 CK-positive cells per 2 x 10(6) bone marrow cells (mean, 35 months) than in patients with <or=2 CK-positive cells per 2 x 10(6 )bone marrow cells (mean, 70 months) or in patients with no CK-positive cells (mean, 86 months). Multivariate analysis confirmed that >2 CK-positive cells per 2 x 10(6) bone marrow cells was an independent prognostic factor for tumor-related death (P < .05).

CONCLUSIONS

Not only the mere presence of CK-positive epithelial cells in bone marrow, but also the cell number, correlates with prognosis. Our findings suggest that classifying CK-positive bone marrow cells in these patients will facilitate future studies.

Lymph node micrometastasis and its correlation with MMP-2 expression in gastric carcinoma

AIM: To examine matrix metalloproteinase-2 (MMP-2) expression in gastric cancer tissues and to evaluate its relationship with lymph node micrometastasis.

METHODS: The authors studied 850 lymph nodes resected from 30 patients with gastric carcinoma who underwent gastrectomy with lymphadenectomy using reverse transcription polymerase chain reaction (RT-PCR) assay in addition to H-E staining. MMP-2 expression of the tumor tissues was detected by immunohistochemical technique (EliVision^TM plus).

RESULTS: MMP-2 expression was positive in 21 (70%) cases and negative in 9 (30%) cases. No significant correlations were found between MMP-2 expression and other variables such as age, gender, tumor location, tumor diameter, Lauren classification and lymphatic invasion. In contrast, MMP-2 expression correlated significantly with depth of tumor infiltration (P = 0.022), lymph node metastasis (P = 0.030) and tumor differentiation (P = 0.043). Lymph node micrometastases were detected in 77 (12.5%) lymph nodes of 14 (46.7%) gastric carcinoma patients. MMP-2 expression was positive in 12 (85.7%) of the 14 patients with lymph node micrometastasis, and in 9 (56.3%) of the 16 patients without lymph node micrometastasis (P = 0.118).

CONCOUSION: Our results demonstrate that MMP-2 expression has significant correlation with tumor invasion, tumor differentiation and lymph node metastases. MMP-2 expression may be an important biological characteristics and significant prognostic parameter of gastric carcinoma. We also conclude that MMP-2 may participate in the development of lymph node micrometastasis of gastric carcinoma. Further investigations are needed to draw a conclusion.

Biological significance of isolated tumor cells and micrometastasis in lymph nodes evaluated using a green fluorescent protein-tagged human gastric cancer cell line

PURPOSE

The biological significance of isolated tumor cells and micrometastasis in lymph node defined by the International Union against Cancer remains essentially unknown because of the lack of appropriate animal models. In the present study, we developed a lymph node micrometastasis model featuring a human gastric cancer cell line tagged with green fluorescent protein gene (GCIY-EGFP), which allows visualization of even isolated tumor cells in the development of metastasis without histologic procedure. Using this model, we investigated the effect of surgery and chemotherapy on the growth of early-phase metastasis formation in the lymph nodes.

EXPERIMENTAL DESIGN

The time course of spontaneous inguinal lymph node metastasis after s.c. inoculation of GCIY-EGFP cells into nude mice was examined with fluorescence dissecting microscopy. Then, the effects of surgical removal of the primary tumor with or without anti-asialo GM1 treatment or postoperative chemotherapy on the growth of isolated tumor cells and micrometastasis in the lymph nodes were examined.

RESULTS

GCIY-EGFP cells were found to metastasize spontaneously to the inguinal lymph nodes to form isolated tumor cells, micrometastasis, and, finally, develop macroscopic metastasis at 1 to 2, 3 to 5, and 5 weeks postinjection, respectively. When the primary tumors were removed within 2 weeks of inoculation, isolated tumor cells, but not micrometastasis, in the lymph nodes regressed by 4 weeks after surgery in all the mice examined (five of five). This spontaneous regression of isolated tumor cells was completely reversed by anti-asialo GM1 treatment, which could deplete natural killer cells effectively in nude mice. Chemotherapy following resection of the primary tumor at an early stage partially eliminated the remaining micrometastasis in the lymph nodes.

CONCLUSIONS

These results suggest that isolated tumor cells in the regional lymph nodes regressed by removal of the primary tumor mainly via natural killer cell-mediated antitumor activity and that micrometastasis in the lymph nodes could be effectively eliminated by the postoperative chemotherapy.

Preventive effect of oral administration of 6-(methylsulfinyl)hexyl isothiocyanate derived from wasabi (Wasabia japonica Matsum) against pulmonary metastasis of B16-BL6 mouse melanoma cells

AIM

Effect of oral administration of 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC) or a 6-MITC-containing T-wasabi fraction from wasabi root (Wasabia japonica Matsum) to inhibit the macroscopic pulmonary metastasis was studied with a murine B16-BL6 melanoma model.

METHOD

Two administration routes, subcutaneous or intravenous, and two administration times, prior to or concomitant with tumor inoculation, of 6-MITC or T-wasabi against the metastatic foci formation in C57BL/6J mouse lungs were compared.

RESULTS

The number of metastasized foci per lung in either subcutaneous or intravenous injection was significantly reduced by intake of 6-MITC or a T-wasabi fraction. The maximum reduction by a T-wasabi fraction reached to 82%. Fifty-six percent of foci formation was inhibited by a 2 week-prior administration of 6-MITC (200 microM), whereas only 27% inhibition was obtained by a concomitant administration with tumor inoculation. Neither 6-MITC nor T-wasabi at tested concentrations showed any toxic effects.

DISCUSSION

Together with our previous results, a component of the Japanese pungent spice, wasabi appears to inhibit not only tumor cell growth but also tumor metastasis. Therefore, 6-MITC from wasabi is apparently a useful dietary candidate for controlling tumor progression.

Impact of skip metastasis in gastric cancer

BACKGROUND

Several studies have shown the features of skip metastasis in other cancers besides gastric cancer. Since minimally invasive surgery has been applied to gastric cancer, the concerns and awareness of skip metastasis have grown in the medical community. We conducted the present retrospective study to reveal the clinicopathological characteristics of patients with skip metastasis. We also wished to clarify the clinical impact of skip metastasis for gastric cancer.

METHODS

Five hundred and eighty-nine patients having lymphatic metastases were enrolled in the present study. Among them, 266 patients had positive nodes extending into the N2 group. We divided these patients into the skip positive (+) and the skip negative (-) group, and we comparatively analysed clinicopathological factors and calculated the survival probabilities for the two groups.

RESULTS

The skip (+) and skip (-) groups involved 14 (5.3%) and 252 (94.7%) patients, respectively. Of all the investigated factors, a significant difference between two groups was observed only in the total number of retrieved nodes. Stations of skip nodes were along left gastric (7), anterior common hepatic (8a), celiac (9), splenic (11) artery and right paracardial nodes (1). The survival curves calculated in the present study did not show any statistical differences between the groups.

CONCLUSIONS

Due to problems of skip metastasis in gastric cancer, D2 lymph node dissection should be performed until sentinel node detection is feasible and reliable. The potential risk from skip metastasis is not great and skip metastasis itself should not be a major consideration in therapeutic decisions.

Clinical relevance of occult tumor cells in lymph nodes from gastric cancer patients

The current method for staging in gastric cancer is not sufficient as even after a complete primary tumor resection, patients with node-negative gastric cancer suffer from disease recurrence. In this study, the relation between disease recurrence and the presence of occult tumor cells (OTC) in lymph nodes from gastric cancer patients was evaluated. In a case-control design, lymph nodes from 40 cases (disease recurrence) and 41 controls (no disease recurrence and followed for at least five years) with gastric cancer were examined for the presence of OTC, that comprised micrometastases (MM; >0.2 mm and < or =2.0 mm) and isolated tumor cells (ITC; < or =0.2 mm). The original hematoxylin and eosin-stained sections of all lymph nodes from cases and controls were previously considered as tumor-negative by the local pathologist. Fresh hematoxylin and eosin-stained sections were screened by conventional microscopy. Histologic sections stained by immunohistochemistry with anticytokeratin antibodies CAM5.2 were screened by conventional and automated microscopy. Tumor cells were detected in lymph nodes from 40 of 81 (49%) patients. There was no significant difference in the presence of OTC, MM, or ITC between the case and control groups (P = 0.658, P = 0.691, P = 0.887, respectively). However, significantly more cases presented with 20% or more OTC-positive lymph nodes (P = 0.015). A multivariate logistic regression analysis showed that examination of less than five lymph nodes (odds ratio, 13.8; 95% confidence interval, 1.6-120.6, P = 0.018) was the only significant independent risk factor for disease recurrence, especially for locoregional disease recurrence (odds ratio, 20.4; 95% confidence interval, 2.2-190.8, P = 0.008). A similar analysis for distant disease recurrence showed a percentage of 20% or more OTC-positive lymph nodes to be the only significant independent risk factor (odds ratio, 15.6, 95% confidence interval, 1.6-151.4, P = 0.018). The sensitivity of immunohistochemistry evaluated by microscopy to identify cases with 20% or more OTC-positive lymph nodes increased from 8% for conventional microscopy to 22% for automated microscopy (McNemar's test, P = 0.063). The mere presence of OTC-positive lymph nodes in gastric cancer patients did not predict disease recurrence. However, the number of examined lymph nodes and the percentage of OTC-positive lymph nodes were independent risk factors for locoregional disease recurrence and distant disease recurrence, respectively. Automated microscopy was essential in identifying patients with 20% or more OTC-positive lymph nodes. Therefore, a maximum number of lymph nodes should be removed and meticulously examined for OTC to identify high-risk patients. These patients should be considered for additional treatment.

Detection and clinical implications of minimal residual disease in gastro-intestinal cancer

INTRODUCTION

Metastatic dissemination is an important factor for the prognosis of patients with gastro-intestinal cancer. Exact staging is crucial to determine appropriate multimodal therapeutic strategies. At present, the sensitivity of routinely performed diagnostic techniques is suboptimal for the detection of minimal residual disease (MRD) and occult metastases since the number of disseminated tumour cells (DTCs) is mostly marginal. To amend the verification of DTCs, immunohistochemical and molecular methods were applied to retrieve epithelial cell-specific proteins in non-epithelial tissue of different body compartments or fluids. Many groups have eagerly focussed on the identification of new markers and novel tests, yet specificity and sensitivity of these methods as well as robustness in the clinical setting are frequently missing.

MATERIALS AND METHODS

This review critically evaluates the prognostic impact of MRD in patients with pancreatic, colorectal and gastric cancer by outlining those studies showing diagnostic results of DTC detection in lymph nodes, bone marrow, venous blood and peritoneal lavage, some of which present novel strategies.

CONCLUSION

The analysed data concerning MRD in gastro-intestinal cancers reveal that results are undesirably heterogeneous. From a critical point of view, many clinical studies missed their chance because of small cohort size; moreover, methodological standardisation is generally lacking. On the other hand, the very encouraging results achieved so far, together with the comprehensive analyses of a few research groups, foster the prediction that DTC/MRD issues will soon expand the standard TNM classification.

Prognostic value of nodal micrometastases in patients with cancer of the gastro-oesophageal junction

AIMS

Aim of this study was to examine the presence and the prognostic impact of immunohistochemically identified nodal micrometastases in patients with gastro-oesophageal junction (GEJ) carcinomas.

METHODS

Between January 1988 and December 2000, 148 patients underwent a radical (R0) resection with a two-field lymphadenectomy for a GEJ carcinoma. Specimens of 60 patients in whom conventional haematoxylin and eosin (H & E) examination did not demonstrate lymph-node metastases (pN0) were available for immunohistochemical (IHC) analysis using antibodies AE1/AE3 directed against cytokeratins. Paraffin embedded material of all retrieved lymph nodes in these patients were serially sectioned and analysed by one pathologist after H & E examination for the presence of micrometastases by IHC.

RESULTS

In 60 resection specimens initially staged as pN0 a total of 524 lymph nodes were available for IHC analyses. Micrometastases were detected in 126 out of 524 lymph nodes (24%), corresponding with 18 of the 60 patients (30%) who were upstaged by this technique. Compared with the pN0 group, the disease free survival (DFS) was significantly lower in patients with nodal involvement at IHC (p<0.001). Survival of patients with IHC identified micrometastatic disease was comparable to those with H & E positive lymph nodes.

CONCLUSIONS

Micrometastases in regional nodes were detected by cytokeratin-specific IHC in 30% of radical resected GEJ tumours without overt nodal involvement. Their presence conveys a worse prognosis with a significant reduced DFS, suggesting that the finding of micrometastases should be included in the staging system.

Expression of vascular endothelial growth factor (VEGF)-C in preoperative biopsy specimens and metastatic foci of regional lymph nodes in submucosal gastric carcinoma

BACKGROUND: Vascular endothelial growth factor (VEGF)-C is implicated in lymphangiogenesis, however the exact role of VEGF-C in promoting lymphatic spread of cancer cells remains largely unknown. METHODS: The expression of VEGF-C was immunohistochemically determined in 97 endoscopic biopsy specimens from 46 patients with submucosal gastric carcinoma (SGC). Nodal metastases including micrometastasis and isolated tumor cells (ITC) were evaluated by immunohistochemical staining for cytokeratin in 1650 lymph nodes, and tumor cells in these metastatic nodes were also examined for VEGF-C expression. RESULTS: In biopsy samples, VEGF-C was positively detected in 21 (47%) patients. Metastases were identified in 46 (2.8%) nodes from 15 (33%) patients. Metastases were detected in 39 nodes by hematoxylin-eosin (H&E) staining and in additional 7 nodes as ITC by immunohistochemical staining. The rate of lymph node metastases was significantly correlated with VEGF-C expression in biopsy samples (p < 0.05). The positive and negative predictive values of VEGF-C in biopsy specimens for nodal metastasis were 44 %(10/21) and 80% (20/25), respectively. Among the 46 metastatic nodes, tumor cells in 29 (63%) nodes positive patients expressed VEGF-C, whereas those in 17 (37%) nodes did not. VEGF-C expression was high in macronodular foci in medullary areas, whereas more than half of ITC or micrometastasis located in peripheral sinus lacked the expression of VEGF-C. CONCLUSIONS: Despite the significant correlation, immunodetcetion of VEGF-C in endoscopic biopsy specimens could not accurately predict the nodal status, and thus cannot be applied for the decision of the treatment for SGC. VEGF-C may not be essential for lymphatic transport, but rather important to develop the macronodular lesion in metastatic nodes.

Significance of isolated tumor cells in lymph nodes among gastric cancer patients

PURPOSE

To determine the frequency and prognostic impact of isolated tumor cells (ITC) in regional lymph nodes judged to be tumor free in conventional histopathology among gastric cancer patients.

METHODS

Among 161 patients who underwent gastrectomy and D2-lymphadenectomy, 56 were staged pN0(35%). Archival paraffin blocks of 1148 resected regional lymph nodes of those pN0 patients were reevaluated for ITC using monoclonal antibody Ber-EP4. Patients with and without ITC were compared with regard to the distribution of various clinicopathological factors. Prognostic impact of ITC was tested in uni- and multivariate analysis.

RESULTS

Of 56 pN0 patients, 33 (59%) exhibited single Ber-Ep4 immunoreactive cells or small cell clusters in at least one lymph node. The occurrence of ITC was not dependent on other clinicopathological factors. ITC impaired patients' prognoses significantly in uni- as well as multivariate analyses [estimated 5-year survival rate: 82% for pN0((i-))vs 58% for pN0((i+))(p = 0.059) and 15% for pN1/2 (p = 0.0005 and p < 0.0001, respectively)].

CONCLUSION

ITC are a frequent event in apparently tumor-free lymph nodes of gastric cancer patients and are overlooked by conventional histopathology. They are encountered even in limited stages of disease and impair patients' prognoses. This should be borne in mind when advocating local resection for early gastric cancer.

Minimal residual disease in gastric cancer

In curatively resected gastric cancer, the incidence of distant relapse is as high as 30%. Although the most important factor contributing to the local control of the tumor is the microscopic tumor-free margin of the surgical resection, the occurrence of distant metastases is in many cases due to preoperative or perioperative tumor cell dissemination. In addition to the established TNM staging system, disseminated tumor cells may serve as independent prognostic factors influencing patient outcome after curative surgery. Basically, in gastric cancer three compartments have been identified in which single tumor cells may be shed: lymph nodes, peritoneal cavity, and bone marrow. Assessment of resected regional lymph nodes with monoclonal antibodies directed against cytokeratin antigens leads to an upstaging in comparison with conventional histology. Nodal micrometastases detected by immunohistochemistry result in an upstaging of up to 36% of patients. However, their prognostic significance remains controversial. Local dissemination of tumor cells in the peritoneal cavity determines the outcome in advanced gastric cancer and diffuse-type carcinoma. Patients with negative peritoneal washings seem to have a more favorable prognosis. Moreover, with the use of these diagnostic tools, patient subpopulations may be identified which profit from intraperitoneal therapy regimens. Diffuse hematogenous tumor cell dissemination into the bone marrow has been shown to be a prognostic factor in several studies. In our own population of 180 gastric cancer patients, bone marrow cells were screened immunohistochemically with a monoclonal antibody directed against cytokeratin 18 (CK18). In 95 patients (53%), CK2-posititve cells were detected. In a multivariate analysis, the independence of the presence of three or more disseminated tumor cells per 10(6) mononuclear cells was proven to be a prognostic factor in patients with intestinal-type tumors, pT1/2 status, and pN0 status. In conclusion, the TNM status only partially reflects the actual extent of systemic disease in patients with resected gastric cancer. The assessment of minimal residual disease is valuable in estimating the prognosis in many patients. In the future, staging systems will have to not only include TNM data but also provide specific information on biological properties of residual cancer cells in order to establish more exact prognostic estimates and provide patients with an individually tailored multimodal treatment.

Pathological staging and therapy of oesophageal and gastric cancer

Oesophageal and gastric cancers are a significant cause of morbidity and mortality worldwide. Despite improvements in surgical techniques, radiation and chemotherapy, the prognosis of both cancers remains poor. Immunohistochemical and experimental studies indicate that the concept of micrometastasis is applicable to oesophageal and gastric cancer. New staging approaches, including immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) of various markers, have been proposed for a more accurate staging of oesophageal and gastric cancer. Preliminary results suggest that real-time RT-PCR of markers for intestinal differentiation, such as guanylyl cyclase C (GC-C), might be useful for both the detection of premalignant conditions, such as intestinal metaplasia and the detection of micrometastasis from adenocarcinoma of the upper intestinal tract. Standard curative treatment options for oesophageal cancer include surgery or chemoradiotherapy. Chemotherapy is an option for the treatment of advanced and recurrent oesophageal cancer. Standard curative treatment for gastro-oesophageal junction and gastric cancer includes surgery and adjuvant chemoradiotherapy. Chemotherapy is an option for the treatment of advanced and recurrent gastric cancer.

Prognostic impact of lymphatic and/or blood vessel invasion in patients with node-negative advanced gastric cancer

BACKGROUND

Heterogeneous survival rates in patients with similar clinicopathologic characteristics or molecular prognostic markers have been noted. This study was conducted to evaluate the prognostic effect of lymphatic and/or blood vessel invasion (LBVI), identified by routine hematoxylin and eosin staining, on the outcome of patients with node-negative advanced gastric cancer.

METHODS

A total of 280 patients who underwent curative gastrectomy for advanced gastric cancer without lymph node metastasis were retrospectively reviewed. Univariate and multivariate analyses of the clinicopathological features, recurrences, and prognoses of patients with and without LBVI were performed.

RESULTS

Lymphatic vessel invasion (LVI) was noted in 20.0%, blood vessel invasion (BVI) in 5.4%, and either LVI or BVI in 22.5%. None of the clinicopathologic features was related to LBVI. Patients with LBVI had a recurrence rate of 26.8%, whereas patients without LBVI had a recurrence rate of 13.5% (P =.018). The 5-year survival rates were 82.4% for patients without LBVI and 67.1% for patients with LBVI (P =.0222). LBVI was shown to be an independent risk factor for recurrence (relative risk, 2.30; 95% confidence interval, 1.06-4.99) and poor prognosis (relative risk, 1.88; 95% confidence interval, 1.07-3.29).

CONCLUSIONS

LBVI is an adverse prognostic indicator and the presence of LBVI seems to provide useful information for the prognosis and clinical management of patients with node-negative advanced gastric carcinoma.

Prognostic relevance of immunohistochemically detected lymph node micrometastasis in patients with gastric carcinoma

BACKGROUND

Micrometastases consisting of one to a few cells in lymph nodes resected during gastrectomy are difficult to identify using conventional hematoxylin and eosin (H&E) stains. It has been shown that immunostaining for cytokeratins is effective in detecting lymph node micrometastasis in a variety of human tumors, but only a few previous reports demonstrated its use in the treatment of patients with early and advanced gastric carcinoma, and those reports had conflicting results.

METHODS

In this study, 3625 regional lymph nodes that were dissected in gastrectomy specimens from 153 patients with early-stage gastric carcinoma (46 patients) and advanced gastric carcinoma (107 patients) were immunostained with the anticytokeratin cocktail AE1/3 for micrometastasis (median, 23 lymph nodes; range, 8-66 lymph nodes). Micrometastasis (MM) was defined as a single tumor cell or clusters of tumor cells that were missed on conventional examination with H&E stains but were detected by immunostaining with broad-spectrum anticytokeratin antibodies.

RESULTS

Lymph node metastasis (LNM) was detected in 609 lymph nodes (17%) by H&E staining. MM was identified in another 191 of the remaining lymph nodes (6.3%) from 75 patients. Twenty-eight of those patients were up-staged. There was a significant correlation between MM and depth of tumor invasion (P < 0.01). Patients with MM had a decreased 5-year survival rate (49%) compared with patients without MM (76%) for both early and advanced gastric carcinoma. The effect of MM on survival was most pronounced for patients in the Stage I and LNM negative group.

CONCLUSIONS

Immunohistochemical examination using broad-spectrum anticytokeratin antibodies increased the detection rate of LNM and had a significant impact on staging and survival in patients with gastric carcinoma.

Is D2 lymphadenectomy for gastric cancer a staging tool or a therapeutic intervention?

The extent of lymphadenectomy for gastric cancer is a controversial topic widely debated by those treating the disease. Regional differences in outcome have been noted between patients treated in Japan centers and those treated in Western centers. Technical differences have been investigated within the context of two large, prospective randomized trials, which found no benefit to more extensive lymphadenectomy procedures with increased morbidity. Subsets of patients being treated for cure may benefit from extended resections. The impact of tumor features, such as depth of invasion and number of metastatic lymph nodes, has been described and incorporated into current staging systems. The role of enhanced pathologic evaluation of surgical specimens and impact on staging and treatment strategies is evolving.

Micro-lymph node metastasis and its correlation with cathepsin D expression in early gastric cancer

BACKGROUND AND OBJECTIVES

Limited operations for early gastric cancer (EGC) have been recommended based on data from lymph node (LN) metastasis detected by hematoxylin and eosin (HE) staining. Recently, the clinical importance of micro-LN metastasis has been reported. In this study, the indication of limited operations for EGC was re-evaluated based on the data from micro-LN metastasis detected by cytokeratin (CK) immunostaining. Also, the correlation between micro-LN metastasis and lysosomal acidic protease cathepsin D (CD) expression in primary tumors was evaluated.

METHODS

A total of 5,949 LNs from 160 patients with EGC were stained by anti-CK monoclonal antibody (CAM 5.2). Also, the 160 primary EGCs were stained by CD.

RESULTS

The incidence of LN metastasis increased from 7.5% (12/160) by HE-staining to 27.5% (44 of 160) by CK immunostaining. The incidence of micro-LN metastasis increased according to the depth of tumor invasion (mucosal cancer: 19% and submucosal cancer: 36.8%) and the size of tumors (< or = 1.0 cm: 5.9%, 1.1-2.0 cm: 25.6%, and > 2.1 cm: 31.7%). The CK-staining patterns were classified into the three subgroups (CK-negative, n = 116; single cell type, n = 27; and clustered type, n = 17). The occurrence of cancer recurrence was significantly higher in clustered type (17.6%) than in single cell type (3.7%) and in CK-negative (0%, P < 0.0001). The mean percentage of CD-positive cancer cells of primary tumors in clustered type (17.2%) was significantly higher than in single cell type (12.3%) and in CK-negative (7.5%, P = 0.0036).

CONCLUSIONS

The acidic protease CD may play an important role of cancer metastasis in EGC. The limited operation without lymphadenectomy should be indicated for EGC with CD-negative.