Predictive factors for lymph node metastasis in early gastric cancer with signet ring cell histology and their impact on the surgical strategy: analysis of single institutional experience

Development and validation of a predictive model associated with lymph node metastasis of gastric signet ring carcinoma patients

The risk factors for lymph node metastasis (LNM) in patients with gastric signet ring cell carcinoma (GSRC) have not been well-defined. This study was designed to prognosticate LNM in patients with GSRC by constructing and verifying a nomogram. A total of 2789 patients with GSRC from the Surveillance, Epidemiology, and End Results (SEER) database and Yijishan Hospital of Wannan Medical College (YJS) were retrospectively reviewed. A predictive model was established using logistic regression based on the SEER cohort. The performance of the model was evaluated using the concordance index (C-index) and decision curve analysis (DCA). In addition, its robustness was validated using the YJS cohort. Four independent predictors of LNM were identified in the SEER cohort. Next, a nomogram was constructed by incorporating these predictors. The C-index were 0.800 (95% confidence interval [CI] = 0.781-0.819) and 0.837 (95% CI = 0.784-0.890) in the training and external validation cohorts, respectively. The outcomes of DCA supported good clinical benefits. The proposed model for evaluating the LNM in patients with GSRC can help to avoid the misdiagnosis risk of N-stage, assist to screen the population suitable for neoadjuvant therapy and help clinicians to optimize clinical decisions.

Poorly cohesive cells gastric carcinoma including signet-ring cell cancer: Updated review of definition, classification and therapeutic management

While the incidence of gastric cancer (GC) in general has decreased worldwide in recent decades, the incidence of diffuse cancer historically comprising poorly cohesive cells-GC (PCC-GC) and including signet ring cell cancer is rising. Literature concerning PCC-GC is scarce and unclear, mostly due to a large variety of historically used definitions and classifications. Compared to other histological subtypes of GC, PCC-GC is nevertheless characterized by a distinct set of epidemiological, histological and clinical features which require a specific diagnostic and therapeutic approach. The aim of this review was to provide an update on the definition, classification and therapeutic strategies of PCC-GC. We focus on the updated histological definition of PCC-GC, along with its implications on future treatment strategies and study design. Also, specific considerations in the diagnostic management are discussed. Finally, the impact of some recent developments in the therapeutic management of GC in general such as the recently validated taxane-based regimens (5-Fluorouracil, leucovorin, oxaliplatin and docetaxel), the use of hyperthermic intraperitoneal chemotherapy as well as pressurized intraperitoneal aerosol chemotherapy and targeted therapy have been reviewed in depth for their relative importance for PCC-GC in particular.

Prevalence of Regional Lymph Node Metastasis of Mucosal Gastric Signet Ring Cell Carcinoma: Analysis of the Collaborative Stage Data Survey of the Korean Central Cancer Registry

INTRODUCTION

Patients with very early-stage gastric signet ring cell carcinoma (SRC) are eligible for minimally invasive treatment, like endoscopic submucosal dissection. However, population-based data on regional lymph node metastasis (LNM) and distant metastasis of gastric SRC are lacking. This study aimed to identify the prevalence of LNM and distant metastasis in mucosal cancer (T1a) of gastric SRC.

METHODS

The Collaborative Stage Data Survey was performed by the Korean Center of Cancer Registry between 2010 and 2015 to establish collaborative stage data of the stomach, colon, rectum, rectosigmoid junction, and breast. From the survey data, information on patients with gastric SRC was extracted for analysis. Variables including age, sex, diagnosis date, primary site, tumor size, histology, American Joint Committee on Cancer staging system scores, and Surveillance, Epidemiology, and End Results summary stage were analyzed.

RESULTS

A total of 1,335 (65.7%) patients had mucosal gastric SRC, and 1,189 (89.1%) patients had surgery and 134 (10%) had endoscopic treatment. Of them, 1,283 (96.1%) patients did not have regional LNM, and 52 (3.9%) patients had regional LNM and 6 (0.4%) had distant metastasis. The hazard ratios of LNM and distant metastasis were 14.98 (95% CI: 4.18-53.2) and 10.09 (95% CI: 2.30-44.17).

CONCLUSIONS

Reginal LNM and distant metastasis occur very less in mucosal gastric SRC, but they are associated with an increased risk of cancer-related death. Even in early stage, surgery should be considered as a standard treatment of mucosal gastric SRC.

Laparoscopic Prophylactic Total Gastrectomy for Hereditary Diffuse Gastric Cancer in CDH1 Mutation Carriers

Background: Patients with hereditary diffuse gastric cancer (HDGC) and germline mutations in the E-cadherin gene, CDH1, have a very high cumulative lifetime risk of developing diffuse gastric cancer. In these patients, it is formally recommended to perform a prophylactic total gastrectomy (PTG). Materials and Methods: We analyzed the course of patients with HDGC who have undergone PTG in our institution. Pedigree analysis, preoperative screening results, operative course, postoperative data, and complete stomach pathologic examination were performed in all patients. Results: Seven patients with confirmed CDH1 mutation underwent PTG, five were women, and average age was 27 years (range 17-42). Signet ring cell carcinoma was found in 1 patient in the preoperative surveillance endoscopic biopsies. Laparoscopic PTG was performed in all patients. There were two complications, an intestinal obstruction that required reintervention and an asymptomatic esophagojejunal anastomosis leak that resolved with conservative treatment. In all gastrectomy specimens, intramucosal signet ring cell carcinoma foci limited to the lamina propria were found (range 1-31), 83.5% were in the body-fundus region. The mean follow-up was 28.5 months (range 8-72). The mean weight loss was 9% (range 2-18). Postoperative symptoms associated with Dumping syndrome were the most frequent. All the patients reported of being very satisfied with the procedure and of having a better quality of life than expected before the procedure. Conclusion: Laparoscopic PTG is an excellent resource to prevent the development of advanced diffuse gastric cancer (DGC) in patients with HDGC with CDH1 mutation. The procedure was well tolerated with a high satisfaction rate and very good functional results. It should be considered in these patients due to the high risk of developing advanced DGC and the lack of effective and reliable surveillance studies.

Gastric Signet Ring Cell Carcinoma: Current Management and Future Challenges

Recent advances in the epidemiology, pathology, molecular mechanisms, and combined modality therapy (CMT) fields have shown that gastric signet ring cell carcinoma (GSRC) should be considered a distinct cancerous entity. Clinical management of this cancer is challenging, with chemoradioresistance and poor outcomes in advanced stages. Pathological and molecular sets of GSRC demonstrate different features of poor cohesion and differentiation according to the WHO, Japanese Gastric Cancer Association, and Laurén classifications. These features also result in poor response to adjuvant and neoadjuvant chemoradiotherapy. Certain studies of GSRC showed the disputed effectiveness of hyperthermic intraperitoneal chemotherapy and immunotherapy. Our aim was to discuss how an improved understanding of these therapeutic benefits may provide better treatment selection for patients, and therefore improve survival. The challenges in the new understanding of GSRC in routine practice and pathology, and the current limitations of treatment will also be discussed.

Predictive Factors for Lymph Node Metastasis and the Effect on Survival in Early Gastric Cancer Patients with Radical Gastric Resection

Objectives

Selected patients with early gastric cancer (GC) are treated endoscopically. Lymph node metastasis (LNM) in the T1 stage may also be detected during surgical resection for early GC. The aim of this study was to determine factors associated with LNM and the effect on survival.

Methods

A total of 63 patients with tumor invasion stage T1a or T1b who were operated on for early GC between 2010 and 2018 were included in the study. Parameters were investigated retrospectively to identify predictive factors for LNM and overall survival. Significance was defined with a 2-sided p-value of <0.05.

Results

Among the 63 patients, 21 (33.3%) had LNM. Lymphovascular invasion (LVI) (p=0.02) and a high-grade tumor (p=0.02) were significantly associated with LNM. The overall survival rate was 73.0%. The number of patients with LNM was greater among the deceased patients compared with the censored group (p=0.03). The median follow-up time of the entire group was 28 months (range: 12-55 months) while it was 23 months (range: 7-39 months) in the deceased group and 33.5 months (15.5-60 months) in the censored group (p=0.06). The mean survival was 62.36 months in patients with LNM and 71.99 months in those without LNM (p=0.09). The cut-off value determined for the neutrophil-to-lymphocyte ratio (NLR) was 2.33 and it was an effective value in survival analysis (p<0.05).

Conclusion

Surgical treatment should be considered for early GC patients with high-grade tumors and cases demonstrating LVI. The overall survival was shorter in patients with a high NLR value and LNM.

Feasibility of endoscopic treatment and predictors of lymph node metastasis in early gastric cancer

BACKGROUND

Endoscopic submucosal dissection (ESD) has been routinely performed in applicable early gastric cancer (EGC) patients as an alternative to conventional surgical operations that involve lymph node dissection. The indications for ESD have been recently expanded to include larger, ulcerated, and undifferentiated mucosal lesions, and differentiated lesions with slight submucosal invasion. The risk of lymph node metastasis (LNM) is the most important consideration when deciding on a treatment strategy for EGC. Despite the advantages over surgical procedures, lymph nodes cannot be removed by ESD. In addition, whether patients who meet the expanded indications for ESD can be managed safely remains controversial.

AIM

To determine whether the ESD indications are applicable to Chinese patients and to investigate the predictors of LNM in EGC.

METHODS

We retrospectively analyzed 12552 patients who underwent surgery for gastric cancer between June 2007 and December 2018 at the Affiliated Hospital of Qingdao University. A total of 1262 (10.1%) EGC patients were eligible for inclusion in this study. Data on the patients’ clinical, endoscopic, and histopathological characteristics were collected. The absolute and expanded indications for ESD were validated by regrouping the enrolled patients and determining the positive LNM results in each subgroup. Predictors of LNM in patients were evaluated by univariate and multivariate analyses.

RESULTS

LNM was observed in 182 (14.4%) patients. No LNM was detected in the patients who met the absolute indications (0/90). LNM occurred in 4/311 (1.3%) patients who met the expanded indications. According to univariate analysis, LNM was significantly associated with positive tumor marker status, medium (20-30 mm) and large (>30 mm) lesion sizes, excavated macroscopic-type tumors, ulcer presence, submucosal invasion (SM1 and SM2), poor differentiation, lymphovascular invasion (LVI), perineural invasion, and diffuse and mixed Lauren’s types. Multivariate analysis demonstrated SM1 invasion (odds ration [OR] = 2.285, P = 0.03), SM2 invasion (OR = 3.230, P < 0.001), LVI (OR = 15.702, P < 0.001), mucinous adenocarcinoma (OR = 2.823, P = 0.015), and large lesion size (OR = 1.900, P = 0.006) to be independent risk factors.

CONCLUSION

The absolute indications for ESD are reasonable, and the feasibility of expanding the indications for ESD requires further investigation. The predictors of LNM include invasion depth, LVI, mucinous adenocarcinoma, and lesion size.

Cellular magnetic resonance imaging: in vivo tracking of gastric cancer cells and detecting of lymph node metastases using microparticles of iron oxide in mice

Background

Monitoring the fate of implanted cells over time in an experimental animal may provide a new way to track the metastatic process. Lymph node metastase is of extremely importance for the prognostic prediction of gastric carcinoma. The aim of this study was to assess the feasibility of magnetic resonance imaging (MRI), using micron-sized superparamagnetic iron oxide particles (MPIO), for monitoring of the fate of gastric cancer cells and detecting the migration of gastric cancer cells through the lymphatic system in a mouse model.

Methods

SGC-7901 gastric cancer cells were labeled with green fluorescent MPIO. The cells were monitored in vitro at multiple time points by staining for iron-labeled cells and by flow cytometric detection of the fluorescent MPIO. MPIO-labeled cells were implanted subcutaneously into nude mice, and cellular MRI was performed at different time points until 35 days postinjection.

Results

The potential for retention of the iron particles in vitro was evaluated. Our results showed that the labeling and uptake efficiency of MPIO reached 90.0% after 24 hrs of incubation, and a small percentage of cells that retained MPIO could be examined until 16 days after labeling. In vivo MRI-based tracking over several weeks in mice revealed regions of signal loss in the primary tumors for up to 5 weeks. Furthermore, small regions of signal void were detected in images of the inguinal lymph nodes in three mice at day 28 postinjection or later, and histological assays confirmed the presence of iron-labeled cancer cells.

Conclusion

This study supports MPIO-based cell tracking is a useful tool for monitoring the fate of gastric cancer cells in mice over time, which may facilitate progress in understanding the mechanisms of early regional lymph node micrometastases.

Serum miR-126 level combined with multi- detector computed tomography in the preoperative prediction of lymph node metastasis of gastric cancer

BACKGROUND

Predicting lymph node metastasis (LNM) accurately is vital to design optimal treatment strategies preoperatively for gastric cancer (GC) patients. However, conventional tumor biomarkers and imaging techniques are not sufficient to predict LNM before surgery. miR-126 has been reported to play important roles in tumor metastasis which may represent a novel tumor biomarker.

OBJECTIVE

To assess the utility of the combination of serum miR-126 and multi-detector computed tomography (MDCT) in predicting LNM preoperatively in GC.

METHODS

Quantitative real-time polymerase chain reaction was performed to examine the serum miR-126 expression levels in 338 GC patients. MDCT was also performed. The cut-off value of preoperative serum miR-126 level for LNM was determined by receiver characteristic curve (ROC) analysis. Logistic regression analysis was used to determine independent predictors for LNM.

RESULTS

The serum miR-126 levels of GC patients with LNM were significantly lower compared with those without LNM (p< 0.05). In addition, the later the N stage was, the lower the serum miR-126 level was in GC patients (p< 0.05). With a cut-off value of 63.4, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of serum miR-126 for predicating LNM were 83.2%, 79.0%, 81.9%, 90.4% and 66.4%, respectively. The combination of serum miR-126 level and MDCT increased the accuracy of MDCT prediction for LNM from 69.2% to 86.7%. Serum miR-126 was an independent predictor for LNM.

CONCLUSIONS

These results indicate for the first time that the combination of serum miR-126 and MDCT is useful for the prediction of LNM in GC.

Tailored treatment for signet ring cell gastric cancer

Gastric cancer with Laurèn diffuse types is increasing in the West. The raising trend is more evident when considering signet ring cells (SRC) histology. However, to control the biologic potential of this GC subtype, some hypotheses of tailored therapeutic strategies for SRC cancers have been made. A review of the literature was performed using the key words "signet ring cells" AND "gastric cancer". Results of literature review were descriptively reported. Endoscopic submucosal dissection (ESD), according to the Japanese extended criteria, could be a therapeutic option for early SRC tumours. However, according to the evidences from more recent studies, indications for ESD to these tumours types should be carefully considered. Concerning the optimal surgical treatment, considering the high lymphotropism and infiltrating behaviour of SRC histotype, the extension of gastric resection should be wider than for intestinal type cancer and laparoscopic surgery should be performed carefully. Moreover, D3 lymphadenectomy could provide a benefit in diffuse-type and SRC histology. The role of surgery in gastric cancer with peritoneal carcinomatosis is still debated and studies on this topic should stratify the good results according to GC histotype. Finally, despite the evidences of chemoresistance in SRC, ongoing randomized trials suggest that multimodal therapy could be the best treatment. Based on the assumption that SRC tumours have specific features, they deserve a specific multimodal treatment. However, a preliminary step to generate strong evidences in this field is the standardization of terminology used to define signet ring cells carcinoma.

Incidence, Survival, and Predictors of Lymph Node Involvement in Early-Stage Gastric Signet Ring Cell Carcinoma in the US

INTRODUCTION

The incidence, survival, and propensity for nodal metastasis in early-stage gastric signet ring cell carcinoma have not been defined in the United States. These data are critical determinants for treatment allocation.

METHODS

Cases of gastric signet ring cell carcinoma were extracted from the national SEER database for the years 2004-2013. Age-standardized incidence was derived. Survival was calculated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to identify predictors of nodal metastasis. Exclusion criteria included neoadjuvant radiotherapy and lack of histologic or nodal data.

RESULTS

A total of 10,624 cases were initially identified. The analysis cohort included 506 cases with early T-stage N0M0 disease following exclusions. The incidence was 0.094 per 100,000 person-years. The 5-year survival rate was 82.8%. Tumor stage (p < 0.001) and size (p < 0.001) were independent predictors of nodal metastasis. The incidence of nodal involvement for T1a tumors <2 cm was 5.4% (p < 0.004).

CONCLUSION

The incidence of potentially resectable signet ring gastric carcinoma has not changed significantly over the past decade. While presenting with predominantly high-grade histology, early T-stage disease has a high survival rate. Small T1a tumors have low rates of nodal metastasis, suggesting that an endoscopic resection could be considered in this subset.

Clinicopathology and Survival in Patients with Gastroesophageal Reflux After Radical Surgery of Proximal Gastric Cancer

BACKGROUND

Gastroesophageal reflux (GR) after radical resection of proximal gastric cancer (PGC) may influence survival; however, few studies have investigated survival in PGC patients who develop GR following radical resection. This study aimed to correlate the occurrence of GR after proximal gastrectomy (PG) and total gastrectomy (TG) with clinicopathological factors and long-term survival.

METHODS

The PGC patient cohort was retrospectively grouped as follows: postoperative patients with and without GR (NGR). Clinicopathological characteristics and survival data were compared between the two groups.

RESULTS

A total of 88 patients who underwent PG (53%) experienced postoperative GR; however, only 30 patients who underwent TG (14%) experienced GR (P = 0.000). The incidence of GR was significantly associated with surgical procedure (P < 0.01), tumor size (P < 0.01), infiltration depth (P < 0.01), lymph node metastasis (P = 0.018), postoperative distant metastasis (P < 0.01) and recurrence (P = 0.001). The 5-year overall survival of the GR group was significantly worse than that of the NGR group (39.3 vs. 46.5%, respectively; P = 0.046). The PG and TG groups had significantly different 5-year overall survival (45.2 vs. 50.9%, respectively; P = 0.047), and multivariate analysis revealed GR as an independent risk factor associated with poor overall survival.

CONCLUSIONS

Patients who experienced GR after radical resection for PGC were more likely to develop recurrence and metastasis, leading to shorter survival. TG for PGC was associated with a more favorable 5-year overall survival than was PG. Thus, TG should be performed for PGC patients with tumors larger than 5 cm, T3/T4 disease or lymph node metastasis to improve their long-term survival.

Associations between mutations of the cell cycle checkpoint kinase 2 gene and gastric carcinogenesis

Gastric cancer is the most common malignant tumor of the digestive system. The etiology of gastric cancer is complex, and susceptibility at the genetic level remains to be fully elucidated in genetic investigations. In the present study, mutations of the cell cycle checkpoint kinase 2 (CHEK2) gene and its association with gastric cancer were examined. Reverse transcription‑quantitative polymerase chain reaction technology was used to detect the expression of CHEK2 and it was found that the expression of CHEK2 was low in gastric cancer. Using sequencing analysis, it was found that the low expression level of CHEK2 was associated with expression of its mutation. The present study also established a CHEK2‑overexpressing mutant and confirmed that CHEK2 promoted gastric cancer cell proliferation. Overexpression of the CHEK2 mutation was confirmed to promote cancer cell migration and invasion. Furthermore, western blot analysis results revealed that overexpression of the CHEK2 mutation downregulated E‑cadherin and upregulated vimentin expression, indicating the mechanism underlying the altered biological behavior. These results suggested that there was a correlation between mutation of the CHEK2 gene and gastric cancer, and provided an experimental basis for antitumor drug investigation and development according to its mutation target.

Predictive factors for lymph node metastasis in early gastric cancer with signet ring cell histology: a meta-analysis

BACKGROUND

Less invasive surgery is widely used in the treatment of early gastric cancer; however, no definite guidelines exist regarding indications for less invasive surgery to treat early gastric cancer with signet ring cell histology. The aim of this study was to identify risk factors for lymph node metastasis (LNM) in early signet ring cell carcinoma (SRC). An extensive search of PubMed, Embase and the Cochrane library was performed for pertinent articles involving early SRC and LNM.

METHODS

Eligible data (gender, depth of invasion, lymphovascular invasion, size, ulceration, macroscopic type and location) were extracted from the included studies and systematically reviewed via a meta-analysis. Review Manager version 5.3 was used to perform the data processing. The Newcastle-Ottawa Scale was utilized to evaluate the quality of the included articles.

RESULTS

Fourteen studies were included in the final analysis. After meta-analysis, female gender, submucosal invasion, lymphovascular invasion and size >20 mm were associated with LNM in early SRC.

CONCLUSION

Four variables were identified as risk factors for LNM in early SRC. The significance of the results of the present study should be further confirmed in more early SRC patients for future clinical use.

Predictive Factors for Lymph Node Metastasis in Undifferentiated Early Gastric Cancer: a Systematic Review and Meta-analysis

OBJECTIVES

Less invasive surgery is gaining popularity for the treatment of early gastric cancer (EGC), but there are no definitive guidelines for the use of less invasive surgery for the treatment of undifferentiated EGC. The aims of this meta-analysis were to identify potential predictive factors for lymph node metastasis (LNM) in undifferentiated EGC and to guide the personalized therapeutic modality for patients with undifferentiated EGC.

METHODS

An extensive search of the PubMed, Embase, and Cochrane Library databases was performed to identify relevant articles involving undifferentiated EGC and LNM. Eligible data were systematically reviewed through a meta-analysis using Review Manager 5.3.

RESULTS

In total, 23 studies were included in this analysis. The meta-analysis found that the variables sex (female), age (greater than 60 years), tumor size (greater than 20 mm), depth of invasion (submucosal invasion), presence of lymphovascular involvement, presence of ulcer findings, histology type (non-signet ring carcinoma), and tumor location (not in the middle part of the stomach) were significantly associated with LNM.

CONCLUSIONS

Eight variables were identified as predictive factors for LNM in undifferentiated EGC. The significance of these variables should be further confirmed during the process of LNM in undifferentiated EGC patients for future clinical application.

Clinicopathology of Early Gastric Carcinoma: An Update for Pathologists and Gastroenterologists

BACKGROUND

The WHO defines early gastric carcinoma (EGC) as invasive carcinoma up to the submucosal layer, regardless of nodal metastasis. The recent study results indicate that EGC varies in location, histology, nodal metastasis, and prognosis.

SUMMARY

The heterogeneity in EGC may be related to various types of epithelial stem cells. The most important stem cells include Lgr5+ cells at the base of a gastric unit in the antrum-pylorus-cardia, Mist1+ cells at the isthmus/Troy+ cells at the base in the corpus-fundus, and Sox2+ cells at the base in almost all regions. Dysregulation of these cells along with environmental factors transform stem cells in different regions into malignancy in genetically susceptible populations.

KEY MESSAGE

The 2 most vulnerable regions for EGC have been found along the lesser curvature: the cardia in elderly patients and antrum-angularis in mid-aged and elderly patients. Most hereditary early-onset gastric carcinomas are concentrated in the corpus-fundus of young women. By histology, the most common EGC type is tubular adenocarcinoma in many growth patterns, starting in the neck of a gastric unit. Worse prognosis has been found in early papillary, compared to tubular, adenocarcinoma, related to deeper penetration, more lymphovascular invasion, and more liver and nodal metastases. Contrary to the common belief, intramucosal signet ring cell carcinoma demonstrates low risk of nodal metastasis, comparable to early intestinal-type EGC.

PRACTICAL IMPLICATIONS

The overall risk for nodal metastasis in EGC is low but significant. It is urgent to organize multicenter studies on risk of nodal metastasis in EGC in order to establish more reliable clinical practice guidelines to treat EGC patients.

Upgrading the definition of early gastric cancer: better staging means more appropriate treatment

Since Murakami defined early gastric cancer (EGC) as a "carcinoma limited to the gastric mucosa and/or submucosa regardless of the lymph node status", several authors have focused on the most influential histopathological parameters for predicting the development of lymph node metastases by considering the lymph node status as an important prognostic factor. A few authors have also considered the depth of invasion as one of the keys to explaining the existence of subgroups of patients affected by EGC with poor prognoses. In any case, EGC is still considered an initial phase of tumor progression with good prognosis. The introduction of modern endoscopic devices has allowed a precise diagnosis of early lesions, which can lead to improved definitions of tumors that can be radically treated with endoscopic mucosal resection or endoscopic submucosal dissection (ESD). Given the widespread use of these techniques, the Japanese Gastric Cancer Association (JGCA) identified in 2011 the standard criteria that should exclude the presence of lymph node metastases. At that time, EGCs with nodal involvement should have been asserted as no longer fitting the definition of an early tumor. Some authors have also demonstrated that the morphological growth pattern of a tumor, according to Kodama's classification, is one of the most important prognostic factors, thereby suggesting the need to report it in histopathological drafts. Notwithstanding the acquired knowledge regarding the clinical behavior of EGC, Murakami's definition is still being used. This definition needs to be upgraded according to the modern staging of the disease so that the appropriate treatment would be selected.

Redefining early gastric cancer

BACKGROUND

The problem is that current definitions of early gastric cancer allow the inclusion of regional lymph node metastases. The increasing use of endoscopic submucosal dissection to treat early gastric cancer is a concern because regional lymph nodes are not addressed. The aim of the study was thus to critically evaluate current evidence with regard to tumour-specific factors associated with lymph node metastases in "early gastric cancer" to develop a more precise definition and improve clinical management.

METHODS

A systematic and comprehensive search of major reference databases (MEDLINE, EMBASE, PubMed and the Cochrane Library) was undertaken using a combination of text words "early gastric cancer", "lymph node metastasis", "factors", "endoscopy", "surgery", "lymphadenectomy" "mucosa", "submucosa", "lymphovascular invasion", "differentiated", "undifferentiated" and "ulcer". All available publications that described tumour-related factors associated with lymph node metastases in early gastric cancer were included.

RESULTS

The initial search yielded 1494 studies, of which 42 studies were included in the final analysis. Over time, the definition of early gastric cancer has broadened and the indications for endoscopic treatment have widened. The mean frequency of lymph node metastases increased on the basis of depth of infiltration (mucosa 6% vs. submucosa 28%), presence of lymphovascular invasion (absence 9% vs. presence 53%), tumour differentiation (differentiated 13% vs. undifferentiated 34%) and macroscopic type (elevated 13% vs. flat 26%) and tumour diameter (≤2 cm 8% vs. >2 cm 25%).

CONCLUSION

There is a need to re-examine the diagnosis and staging of early gastric cancer to ensure that patients with one or more identifiable risk factor for lymph node metastases are not denied appropriate chemotherapy and surgical resection.