Application of minimally invasive treatment for early gastric cancer

Comparable long-term survival outcomes after endoscopic and gastrectomy treatment of pT1acN0M0 gastric adenocarcinoma in patients who met the expanded criteria

BACKGROUND

Whether the Western pT1acN0M0 gastric cancer (GC) patients who met the Japanese expanded criteria could be the candidates for endoscopic treatment (ET) remains unclear because of unknown long-term survival outcomes.

METHODS

A retrospective cohort study using data from the Surveillance, Epidemiology, and End Results (SEER) program was performed. The survival differences between pT1acN0M0 gastric adenocarcinoma patients who received ET or gastrectomy treatment (GT) were evaluated using multivariate survival analysis.

RESULTS

A total of 314 pT1acN0M0 gastric adenocarcinoma patients who met the expanded criteria were included, 46 patients received ET and 268 patients received GT. pT1acN0M0 gastric adenocarcinoma patients met the expanded criteria underwent ET experienced a similar hazard of cancer-specific death compared with those underwent GT both in the multivariate Cox survival analysis (adjusted hazard ratio [HR]; 1.18, 95% confidence interval [CI] 0.40-3.49; P = 0.766) and the multivariate competing risk model (subdistribution HR [SHR], 1.12, 95% CI 0.38-3.29; P = 0.845). The result that pT1acN0M0 gastric adenocarcinoma patients met the expanded criteria underwent ET experienced comparable survival outcomes to those who underwent GT did not change even compared with those who underwent GT with > 15 lymph nodes examined (adjusted HR, 1.55, 95% CI 0.44-5.49; P = 0.499; SHR, 1.47, 95% CI 0.44-4.88; P = 0.532).

CONCLUSIONS

The ET can be considered in Western pT1acN0M0 gastric adenocarcinoma patients who met the Japanese expanded criteria. However, a prospective study should be warranted.

Computed tomography-based deep-learning prediction of lymph node metastasis risk in locally advanced gastric cancer

Purpose

Preoperative evaluation of lymph node metastasis (LNM) is the basis of personalized treatment of locally advanced gastric cancer (LAGC). We aim to develop and evaluate CT-based model using deep learning features to preoperatively predict LNM in LAGC.

Methods

A combined size of 523 patients who had pathologically confirmed LAGC were retrospectively collected between August 2012 and July 2019 from our hospital. Five pre-trained convolutional neural networks were exploited to extract deep learning features from pretreatment CT images. And the support vector machine (SVM) was employed as the classifier. We assessed the performance using the area under the receiver operating characteristics curve (AUC) and selected an optimal model, which was compared with a radiomics model developed from the training cohort. A clinical model was built with clinical factors only for baseline comparison.

Results

The optimal model with features extracted from ResNet yielded better performance with AUC of 0.796 [95% confidence interval (95% CI), 0.715-0.865] and accuracy of 75.2% (95% CI, 67.2%-81.5%) in the testing cohort, compared with 0.704 (0.625-0.783) and 61.8% (54.5%-69.9%) for the radiomics model. The predictive performance of all the radiological models were significantly better than the clinical model.

Conclusion

The novel and noninvasive deep learning approach could provide efficient and accurate prediction of lymph node metastasis in LAGC, and benefit clinical decision making of therapeutic strategy.

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

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

Integrated DNA and RNA sequencing reveals early drivers involved in metastasis of gastric cancer

Gastric cancer (GC) is the second cause of cancer-related death and metastasis is an important cause of death. Considering difficulties in searching for metastatic driver mutations, we tried a novel strategy here. We conducted an integrative genomic analysis on GC and identified early drivers lead to metastasis. Whole-exome sequencing (WES), transcriptomes sequencing and targeted-exome sequencing (TES) were performed on tumors and matched normal tissues from 432 Chinese GC patients, especially the comparative analysis between higher metastatic-potential (HMP) group with T1 stage and lymph-node metastasis, and lower metastatic-potential (LMP) group without lymph-nodes or distant metastasis. HMP group presented higher mutation load and heterogeneity, enrichment in immunosuppressive signaling, more immune cell infiltration than LMP group. An integrated mRNA-lncRNA signature based on differentially expressed genes was constructed and its prognostic value was better than traditional TNM stage. We identified 176 candidate prometastatic mutations by WES and selected 8 genes for following TES. Mutated TP53 and MADCAM1 were significantly associated with poor metastasis-free survival. We further demonstrated that mutated MADCAM1 could not only directly promote cancer cells migration, but also could trigger tumor metastasis by establishing immunosuppressive microenvironment, including promoting PD-L1-mediated immune escape and reprogramming tumor-associated macrophages by regulating CCL2 through Akt/mTOR axis. In conclusion, GCs with different metastatic-potential are distinguishable at the genetic level and we revealed a number of potential metastatic driver mutations. Driver mutations in early-onset metastatic GC could promote metastasis by establishing an immunosuppressive microenvironment. This study provided possibility for future target therapy of GC.

Comparable long-term outcomes after endoscopic therapy and gastrectomy of early adenocarcinoma of esophagogastric junction: a population-based study

BACKGROUND AND AIMS

Current guidelines recommend consideration of endoscopic therapy (ET) when treating selected early gastric cancers. However, clinical decision-making on ET versus gastrectomy for early adenocarcinoma of esophagogastric junction (AEGJ) remains challenging because of uncertain long-term outcomes.

METHODS

We performed a retrospective cohort study using the Surveillance, Epidemiology, and End Results database from 2004 to 2017 of early AEGJ patients underwent ET or gastrectomy. Multivariate models were used to compare cancer-specific survival (CSS).

RESULTS

Of 881 included early AEGJ patients, 227 (36.2%) patients underwent ET and 654 (63.8%) patients underwent gastrectomy. Early AEGJ patients who underwent ET experienced a similar hazard of cancer-specific death compared with those underwent gastrectomy in both multivariate Cox regression (HR [hazard ratio], 0.93; 95% CI [confidence interval], 0.55-1.56; P = 0.78) and the multivariate competing risk model (subdistribution HR [SHR], 0.86; 95% CI 0.50-1.45; P = 0.56). Propensity score matching was used, 210 patients underwent ET were matched with 210 patients underwent gastrectomy. Patients underwent ET experienced a similar hazard of cancer-specific death compared with those underwent gastrectomy in both multivariate Cox regression (HR, 0.97; 95% CI 0.53-1.77; P = 0.92) and the multivariate competing risk model (SHR, 0.96; 95% CI 0.52-1.77; P = 0.89).

CONCLUSION

Early AEGJ patients who received ET or gastrectomy had comparable long-term outcomes, which lend support to the role of ET in the treatment of these patients.

New Developments in Gastric Neuroendocrine Neoplasms

Purpose of Review

Gastric neuroendocrine neoplasms (g-NENs) are a rare type of stomach cancer. The three main subtypes have different pathogeneses, biological behaviours and clinical characteristics, so they require different management strategies. This article will provide an overview of g-NENs and highlight recent advances in the field.

Recent Findings

Molecular profiling has revealed differences between indolent and aggressive g-NENs, as well as a new somatic mutation responsible for some familial type I g-NENs. Novel biomarkers have been developed which will hopefully improve diagnosis, treatment, risk stratification and follow-up. Patient treatment is also changing, as evidence supports the use of less aggressive options (e.g. endoscopic surveillance or resection) in some patients with more indolent tumours.

Summary

g-NEN heterogeneity poses challenges in understanding and managing this rare disease. More basic science research is needed to investigate molecular pathogenesis, and future larger clinical studies will hopefully also further improve treatment and patient outcomes.

Meningeal carcinomatosis following a curative endoscopic submucosal dissection of early gastric cancer: a case report

Meningeal carcinomatosis (MC) is reported to occur in 4%-15% of patients with solid tumors. MC is not commonly associated with gastric carcinoma and is extremely rare in patients with early gastric cancer (EGC). MC derived from EGC after curative endoscopic submucosal dissection (ESD) has not been reported before. We present a rare case of a 49-year-old patient who developed MC after curative ESD of EGC. The cancer was an ulcerated lesion approximately 1.0 cm in diameter in endoscopic appearance in the minor curvature of the gastric antrum. The pathological examination after ESD indicated high-grade intraepithelial neoplasia (1.3 × 2.1 cm in size) with localized moderately differentiated adenocarcinoma (0-IIc in tumor stage, intestinal type in Lauren classification), which was confined to the mucosal layer with an intact submucosal layer and muscularis propria. The lesion was removed entirely by curative dissection without vertical and horizontal resection margins involvement in pathology. Two months after ESD, the patient was readmitted for severe headache and vomiting. Cytological examination of the cerebrospinal fluid found malignant tumor cells, which were considered by pathologists to have metastasized from the stomach, further confirming MC derived from EGC. The patient's condition deteriorated dramatically, which prevented him from receiving further therapies, such as chemotherapy, and he died 3 days after the diagnosis of MC. In conclusion, EGC can cause MC, even after curative ESD. New neurological manifestations in patients with EGC can alert physicians to a diagnosis of MC, and more attention needs to be paid to evaluating the nervous system and establishing diagnostic and therapeutic strategies as soon as possible.

Is local excision sufficient in selected grade 1 or 2 type III gastric neuroendocrine neoplasms?

PURPOSE

Type III gastric neuroendocrine neoplasms (g-NENs) have historically been regarded as aggressive tumours, hence current guidelines advocate radical surgery with lymph node dissection. Data on the roles of endoscopic or less extensive surgical resections are more limited. The aim of our study is to evaluate the clinicopathological features and long-term outcomes of patients undergoing endoscopic or limited surgical resection for localised grade 1 or 2 type III g-NENs when compared to radical surgery.

METHODS

Retrospective analysis of all patients diagnosed with a localised grade 1 or 2 type III g-NENs across six tertiary NEN centers between 2006 and 2019.

RESULTS

Forty-five patients were diagnosed with a potentially resectable grade 1 or 2 type III g-NEN of whom 36 underwent either endoscopic or surgical resection. No statistically significant differences were found between the three resection groups in terms of patient age, tumour location, grade or size. Only tumour size was found to be significantly associated with poor clinical outcome (p = 0.012) and ROC curve analysis identified tumour size >10 mm as a negative predictor (AUC:0.8030, p = 0.0021). Tumours >10 mm were also more likely to be associated with lymph node metastases on imaging and histology (p = 0.039 and p = 0.026 respectively).

CONCLUSIONS

Localised grade 1 or 2 type III g-NENs had a good prognosis in this series. Tumour size >10 mm was the most significant prognostic factor affecting patient outcome. Endoscopic resection or limited surgical resection is feasible and safe in small type III g-NENs which demonstrate favourable grade 1/2, well differentiated histology.

A genomic-clinicopathologic Nomogram for the preoperative prediction of lymph node metastasis in gastric cancer

BACKGROUND

Preoperative evaluation of lymph node (LN) state is of pivotal significance for informing therapeutic decisions in gastric cancer (GC) patients. However, there are no non-invasive methods that can be used to preoperatively identify such status. We aimed at developing a genomic biosignature based model to predict the possibility of LN metastasis in GC patients.

METHODS

We used the RNA profile retrieving strategy and performed RNA expression profiling in a large GC cohort (GSE62254, n = 300) from Gene Expression Ominus (GEO). In the exploratory stage, 300 GC patients from GSE62254 were involved and the differentially expressed RNAs (DERs) for LN-status were determined using the R software. GC samples in GSE62254 were randomly allocated into a learning set (n = 210) and a verification set (n = 90). By using the Least absolute shrinkage and selection operator (LASSO) regression approach, a set of 23-RNA signatures were established and the signature based nomogram was subsequently built for distinguishing LN condition. The diagnostic efficiency, as well as the clinical performance of this model were assessed using the decision curve analysis (DCA). Metascape was used for bioinformatic analysis of the DERs.

RESULTS

Based on the genomic signature, we established a nomogram that robustly distinguished LN status in the learning (AUC = 0.916, 95% CI 0.833-0.999) and verification sets (AUC = 0.775, 95% CI 0.647-0.903). DCA demonstrated the clinical value of this nomogram. Functional enrichment analysis of the DERs was performed using bioinformatics methods which revealed that these DERs were involved in several lymphangiogenesis-correlated cascades.

CONCLUSIONS

In this study, we present a genomic signature based nomogram that integrates the 23-RNA biosignature based scores and Lauren classification. This model can be utilized to estimate the probability of LN metastasis with good performance in GC. The functional analysis of the DERs reveals the prospective biogenesis of LN metastasis in GC.

Utility of the gastric window in computed tomography for differentiation of early gastric cancer (T1 stage) from muscularis involvement (T2 stage)

OBJECTIVE

To analyze the diagnostic value of using the gastric window in computed tomography for differentiation of early gastric cancer (T1 stage) from muscularis involvement (T2 stage).

MATERIALS AND METHODS

All patients with pathologically confirmed T1 stage and T2 stage gastric cancer and who underwent endoscopic resection or gastrectomy at our institution from January 2011 to November 2018 were examined. Each patient received an enhanced CT scan of the abdomen before the operation. T staging of tumors based on the CT scans was performed independently by two radiologists using the gastric window (width 150-200 HU, level 80-100 HU) and the abdominal window (width 350-400 HU, level 50 HU).

RESULTS

Use of the gastric window to diagnose stage T1 EGC led to an accuracy of 88.9% for observer1 and 91.5% for observer2; use of the abdominal window led to an accuracy of 53.6% for observer1 and 51.6% (38/106) for observer2. Use of the gastric window to diagnose stage T2 led to an accuracy of 85.6% for observer1 and 82.4% for observer2; use of the abdominal window led to an accuracy of 52.3% for both observer1 and observer2. For observer1, use of the gastric window had a diagnostic accuracy of 69.2% for stage T1a and 62.5% for stage T1b; for observer2, the diagnostic accuracy was 65.1% for stage T1a and 67.0% for stage T1b. A Kappa test indicated moderate and substantial inter-observer agreement for T staging with gastric window (κ = 0.598, P < 0.001) and abdominal window (κ = 0.745, P < 0.001).

CONCLUSION

Use of the gastric window in computed tomography provided more accurate staging for T1 and T2 stages of gastric cancer than the conventional abdominal window.

Machine learning predicts lymph node metastasis of poorly differentiated-type intramucosal gastric cancer

To construct a machine learning algorithm model of lymph node metastasis (LNM) in patients with poorly differentiated-type intramucosal gastric cancer. 1169 patients with postoperative gastric cancer were divided into a training group and a test group at a ratio of 7:3. The model for lymph node metastasis was established with python machine learning. The Gbdt algorithm in the machine learning results finds that number of resected nodes, lymphovascular invasion and tumor size are the primary 3 factors that account for the weight of LNM. Effect of the LNM model of PDC gastric cancer patients in the training group: Among the 7 algorithm models, the highest accuracy rate was that of GBDT (0.955); The AUC values for the 7 algorithms were, from high to low, XGB (0.881), RF (0.802), GBDT (0.798), LR (0.778), XGB + LR (0.739), RF + LR (0.691) and GBDT + LR (0.626). Results of the LNM model of PDC gastric cancer patients in test group : Among the 7 algorithmic models, XGB had the highest accuracy rate (0.952); Among the 7 algorithms, the AUC values, from high to low, were GBDT (0.788), RF (0.765), XGB (0.762), LR (0.750), RF + LR (0.678), GBDT + LR (0.650) and XGB + LR (0.619). Single machine learning algorithm can predict LNM in poorly differentiated-type intramucosal gastric cancer, but fusion algorithm can not improve the effect of machine learning in predicting LNM.

Current status of robotic gastrectomy for gastric cancer: comparison with laparoscopic gastrectomy

Robotic systems were developed to overcome limitations of laparoscopic surgery with its mechanical advantages. Along with the technical advances, robotic gastrectomy for gastric cancer is increasing. However, the evidence regarding safety and efficacy for robotic gastrectomy for gastric cancer is not mature yet. Although studies are limited, it is evident that robotic gastrectomy has a longer operation and less blood loss compared with laparoscopic gastrectomy. Studies revealed long-term oncological outcomes after robotic gastrectomy was comparable to those after laparoscopic gastrectomy. Taken together, robotic gastrectomy with systemic lymph node dissection is suggested as a safe procedure with equivalent short- and long-term oncologic outcomes to either laparoscopic or open gastrectomy for the surgical treatment of gastric cancer. However, high cost is the most significant barrier to justify robotic surgery as a routine and standard treatment for patients with gastric cancer. In the meanwhile, robotic surgery will be expansively used as long as technologic developments continue.

Influence of Tumor Location on Lymph Node Metastasis and Survival for Early Gastric Cancer: a Population-Based Study

BACKGROUND

The question that whether the criteria for endoscopic resection of early gastric non-cardia cancer (GNCC) is appropriate for early gastric cardia cancer (GCC) remains unclear. Thus, our aim was to evaluate the influence of tumor location on lymph node metastasis (LNM) and overall survival (OS) for early gastric cancer (GC).

METHODS

A total of 5440 early GC patients in the Surveillance, Epidemiology, and End Results (SEER) database were identified. Multivariable analysis was performed to evaluate the influence of tumor location on LNM and OS for early GC.

RESULTS

The rate of LNM was 17.48% for early GCC patients (232/1327) and 18.62% for early GNCC patients (766/4113). The early GCC patients experienced no significantly different risk of LNM compared with the early GNCC patients (adjusted OR 0.92, 95% CI 0.76-1.12, P = 0.405). The early GC patients were further stratified by node status. Tumor location was not a predictor of OS for node-negative early GC patients (adjusted HR 1.07, 95% CI 0.96-1.21, P = 0.225) but a predictor of OS for node-positive early GC patients (adjusted HR 1.80, 95% CI 1.48-2.20, P < 0.001).

CONCLUSIONS

Tumor location was not a predictor of LNM for early GC patients. Moreover, tumor location was not a predictor of OS for node-negative early GC patients. Thus, the criteria for endoscopic resection of early GNCC might be appropriate for the treatment of early GCC.

Combination of endoscopic submucosal dissection and laparoscopic sentinel lymph node dissection in early mucinous gastric cancer: Role of lymph node metastasis

BACKGROUND

Recent evidence showed that combining endoscopic submucosal dissection (ESD) and laparoscopic sentinel lymph node dissection may avoid unnecessary gastrectomy in treating early mucinous gastric cancer (EMGC) patients with risks of positive lymph node metastasis (pLNM).

AIM

To explore the predictive factors for pLNM in EMGC, and to optimize the clinical application of combing ESD and sentinel lymph node dissection in a proper subgroup of patients with EMGC.

METHODS

Thirty-one patients with EMGC who had undergone gastrectomy with lymph node dissection were consecutively enrolled from January 1988 to December 2016. Univariate and multivariate logistic regression analyses were used to estimate the association between the rates of pLNM and clinicopathological factors, providing odds ratio (OR) with 95% confidence interval. And the association between the number of predictors and the pLNM rate was also investigated.

RESULTS

Depth of invasion (OR = 7.342, 1.127-33.256, P = 0.039), tumor diameter (OR = 9.158, 1.348-29.133, P = 0.044), and lymphatic vessel involvement (OR = 27.749, 1.821-33.143, P = 0.019) turned out to be significant and might be the independent risk factors for predicating pLNM in the multivariate analysis. For patients with 1, 2, and 3 risk factors, the pLNM rates were 9.1%, 33.3%, and 75.0%, respectively. pLNM was not detected in seven patients without any of these risk factors.

CONCLUSION

ESD might serve as a safe and sufficient treatment for intramucosal EMGC if tumor size ≤ 2 cm, and when lymphatic vessel involvement is absent by postoperative histological examination. Combining ESD and sentinel lymph node dissection could be recommended as a safe and effective treatment for EMGC patients with a potential risk of pLNM.

Association between surgical approach and survival following resection of abdominopelvic malignancies

BACKGROUND AND OBJECTIVES

Recent studies demonstrating decreased survival following minimally invasive surgery (MIS) for cervical cancer have generated concern regarding oncologic efficacy of MIS. Our objective was to evaluate the association between surgical approach and 5-year survival following resection of abdominopelvic malignancies.

METHODS

Patients with stage I or II adenocarcinoma of the prostate, colon, rectum, and stage IA2 or IB1 cervical cancer from 2010-2015 were identified from the National Cancer Data Base. The association between surgical approach and 5-year survival was assessed using propensity-score-matched cohorts. Distributions were compared using logistic regression. Hazard ratio for death was estimated using Cox proportional-hazard models.

RESULTS

The rate of deaths at 5 years was 3.4% following radical prostatectomy, 22.9% following colectomy, 18.6% following proctectomy, and 6.8% following radical hysterectomy. Open surgery was associated with worse survival following radical prostatectomy (HR, 1.18; 95% CI, 1.05-1.33; P = .005), colectomy (HR, 1.45; 95% CI, 1.39-1.51; P < .001), and proctectomy (HR, 1.28; 95% CI, 1.10-1.50; P = .002); however, open surgery was associated with improved survival following radical hysterectomy (HR, 0.61; 95% CI, 0.44-0.82; P = .003).

CONCLUSIONS

These results suggest that MIS is an acceptable approach in selected patients with prostate, colon, and rectal cancers, while concerns regarding MIS resection of cervical cancer appear warranted.

Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: Influence of output energy delivery

PURPOSE

The purpose of this study was to quantitatively analyze tissue deformation during radiofrequency (RF) and microwave ablation for varying output energy levels.

METHODS

A total of 46 fiducial markers which were classified into outer, middle, and inner lines were positioned into a single plane around an RF or microwave ablation applicator in each ex vivo bovine liver sample (8 cm × 6 cm × 4 cm, n = 18). Radiofrequency (500 kHz; ~35 W average) or microwave (2.4 GHz; 50-100 W output, ~35-70 W delivered) ablation was performed for 10 min (n = 4-6 each setting). CT images were acquired over the entire liver volume every 15 s. Principle strain magnitude and direction were determined from fiducial marker displacement. Normal and shear strain were then calculated such that negative strain denoted contraction and positive strain denoted expansion. Temporal variations, the final magnitudes, and angles of the strain were compared across energy delivery settings, using one-way ANOVA with post hoc Tukey's tests.

RESULTS

On average, tissue strain rates peak at around 1 min and decayed exponentially over time. No evidence of tissue expansion was observed. The tissue strains from RF and 50 W, 75 W, and 100 W microwave ablation at 10 min were -8.5%, -38.9%, -54.4%, and -65.7%, respectively, from the inner region and -3.6%, -23.7%, -41.8%, and -44.3%, respectively, from the outer region. Negative strain magnitude was positively correlated to energy delivery in the inner region (Spearman's ρ  = -0.99). Microwaves at higher powers (75-100 W) induced significantly more strain than at lower power (50 W) or after RF ablation (P < 0.01). Principal strain angles ranged from 0.8° to -8.1°, indicating that tissue deformed more in the direction transverse to the applicator than along the direction of the applicator.

CONCLUSIONS

The influence of output energy on tissue deformation during RF and microwave ablation was analyzed. Microwave ablation created significantly greater contraction than RF ablation with similar energy delivery. During microwave ablation, more contraction was noted at higher power levels and in proximity to the antenna. Contraction primarily transverse to the antenna produces ablation zones that are more elongated than the original tissue volume.

Effect of Tailored Perigastric Lymph Node Dissection on Gastric Motility in a Canine Model

BACKGROUND

Combination laparoscopic lymph node (LN) dissection and endoscopic resection is a promising treatment for early gastric cancer. However, LN dissection could cause nerve injury and deterioration of motility in the preserved stomach. This experimental study aims to evaluate changes in gastric motility after tailored perigastric regional lymph node dissection without gastrectomy.

MATERIALS AND METHODS

We identified four most frequently involved LN combinations considering tumor location from retrospective reviews of 4697 gastrectomy patients. We randomly assigned 55 dogs to five groups: control (laparotomy only) and four experimental groups with LN dissection without gastrectomy: group 1 (LNs 3, 7, and 8), group 2 (LNs 3, 4, and 6), group 3 (LNs 1, 3, and 7), and group 4 (LNs 3, 4, and 11). Gastric emptying time (GET) was measured using barium-impregnated polyethylene spheres. GET₅₀ and GET₇₅ were the time points when 50% and 75% of the markers, respectively, had emptied from the stomach.

RESULTS

On postoperative days (PODs) 2 and 3, GET_50, GET_75, and proportion of GET₅₀ <4 h in groups 1 and 2 were comparable with controls. However, group 3 showed delayed GET₅₀ and GET₇₅, and groups 3 and 4 demonstrated significantly smaller proportions of GET₅₀ <4 h compared with controls on PODs 2 and 3. This effect resolved by POD 6 and there were no significant differences in GET_50, GET_75, or proportion of GET₅₀ <4 h between the groups.

CONCLUSIONS

Tailored perigastric LN resection without gastrectomy was feasible and acceptable in terms of postoperative motility in the preserved stomach.

Risk Factors of Lymph Node Metastasis in Patients with Early Pure and Mixed Signet Ring Cell Gastric Carcinomas

Background: Early gastric carcinoma (EGC) with pure signet ring cell carcinoma (pSRCC) has been reported to have favourable prognosis and low risk of lymph node metastasis (LNM). However, risk factors of LNM and clinicopathological features for early gastric mixed signet ring cell carcinoma (mSRCC) remain poorly investigated. The aim of this study was to identify risk factors of LNM and compare clinicopathological characteristics and prognosis of early gastric pSRCC with mSRCC.

Methods: This retrospective study was conducted at our center between 2005 and 2015 in 796 patients underwent radical gastrectomies combined with lymph node dissections, A total of 160 patients with early gastric SRCC underwent gastrectomies with lymph node dissections were reviewed, in which 79 cases were pSRCC and 81 cases were mSRCC. Risk factors of LNM and clinicopathologic features of these two groups were statistically compared, including age, gender, tumor location, gross pattern, size, invasion depth, lymphovascular invasion (LVI), helicobacter pylori (Hp) infection, atrophic gastritis, ulcer finding and LNM. Patients were follow-up for post-resection survival. The 5-year survival and disease-specific survival rate were estimated with the Kaplain-Meier method with a log-rank test and compared between the two groups.

Results: Tumor size (P<0.05), invision depth (P<0.05) and LVI (P < 0.0001) were risk factors of LNM, LVI (P < 0.0001) was independent risk factor of LNM in 160 patients. Univariate analysis reviewed LVI (P < 0.0001) as the risk factor in the pSRCC group, and the risk factors of LNM in the mSRCC included LVI (P < 0.0001) and tumor size (P<0.05). Multivariable analysis revealed two independent risk factors in the mSRCC group: 1) tumor size (P < 0.05), and 2) LVI (P < 0.0001). The significant characteristics in two groups included the male gender (P < 0.0001), gross pattern (P < 0.05), LVI (P < 0.01), and Hp infection (P < 0.01). The difference of LNM rate between expanded indication and out of indication in 160 patients was significant (P=0.03). The overall 5-year survival rate for early gastric SRCC was 96.3%. There was no significant difference in the overall survival and disease-specific survival between the two groups.

Conclusions: Although with similar post-resection survival, the independent risk factors of LNM in the early mSRCC group, compared to those in the early pSRCC group, included large tumor size and LVI. Early gastric mSRCC had more aggressive clinicopathological features than pSRCC.

Outcomes of Endoscopic Submucosal Dissection for Early Gastric Cancer with Undifferentiated-Type Histology: A Clinical Simulation Using a Non-Selected Surgical Cohort

Background/Aims

Outcomes of endoscopic submucosal dissection (ESD) for undifferentiated-type early gastric cancer (EGC) need to be further evaluated. We aimed to simulate the outcomes of ESD for undifferentiated-type EGC from a surgical database.

Methods

Among 802 patients who underwent gastrectomy with endoscopic biopsy for poorly differentiated adenocarcinoma (PD-type) or signet ring cell carcinoma (SRC-type), ESD candidates meeting the expanded indication (n=280) were selected by reviewing the endoscopic images. According to the surgical pathologic results, the outcomes of the ESD simulation were evaluated.

Results

Among the candidates, 104 (37.1%) were PD-type and 176 (62.9%) were SRC-type. The curative resection (CR) rate was 42.1%. Among the patients with CR, three patients (2.5%) showed lymph node metastasis (LNM). Three EGCs with CR and LNM were mucosal cancers ≥1.0 cm in size. The CR rate was higher in the SRC-type than in the PD-type (48.3% vs 31.7%, respectively, p=0.007). In the SRC-type, the CR rate was increased, with a smaller size criterion for the ESD indication, but was similar between the 1.0 cm and 0.6 cm criteria (63.3% and 63.6%, respectively), whereas the CR rate was below 50% in all of the different tumor size criteria (2.0 to 0.6 cm) in the PD-type.

Conclusions

In undifferentiated-type EGC, ESD should be considered in selected patients with tumor sizes ＜1 cm and SRC histology.

Clinical Utility of a STAT3-Regulated miRNA-200 Family Signature with Prognostic Potential in Early Gastric Cancer

Purpose: The majority of gastric cancer patients are diagnosed with late-stage disease, for which distinct molecular subtypes have been identified that are potentially amenable to targeted therapies. However, there exists no molecular classification system with prognostic power for early-stage gastric cancer (EGC) because the molecular events promoting gastric cancer initiation remain ill-defined.Experimental Design: miRNA microarrays were performed on gastric tissue from the gp130^F/F preclinical EGC mouse model, prior to tumor initiation. Computation prediction algorithms were performed on multiple data sets and independent gastric cancer patient cohorts. Quantitative real-time PCR expression profiling was undertaken in gp130^F/F-based mouse strains and human gastric cancer cells genetically engineered for suppressed activation of the oncogenic latent transcription factor STAT3. Human gastric cancer cells with modulated expression of the miR-200 family member miR-429 were also assessed for their proliferative response.Results: Increased expression of miR-200 family members is associated with both tumor initiation in a STAT3-dependent manner in gp130^F/F mice and EGC (i.e., stage IA) in patient cohorts. Overexpression of miR-429 also elicited contrasting pro- and antiproliferative responses in human gastric cancer cells depending on their cellular histologic subtype. We also identified a miR-200 family-regulated 15-gene signature that integrates multiple key current indicators of EGC, namely tumor invasion depth, differentiation, histology, and stage, and provides superior predictive power for overall survival compared with each EGC indicator alone.Conclusions: Collectively, our discovery of a STAT3-regulated, miR-200 family-associated gene signature specific for EGC, with predictive power, provides a molecular rationale to classify and stratify EGC patients for endoscopic treatment. Clin Cancer Res; 24(6); 1459-72. ©2018 AACR.

Evaluation of Slug expression is useful for predicting lymph node metastasis and survival in patients with gastric cancer

BACKGROUND

Slug is a transcription factor that activates the epithelial-mesenchymal transition (EMT) process in cancer progression. The aim of our study was to evaluate the clinical significance of Slug expression in gastric cancer.

METHODS

The expression of Slug in gastric cancer tissues of 456 patients who underwent gastrectomy was evaluated by immunohistochemistry using tissue microarrays. Slug expression level was defined by the composite score determined by multiplying the tumor staining scores for intensity and extent. The associations of Slug expression with clinicopathological characteristics and overall and recurrence-free survival were analyzed.

RESULTS

Patients were divided into three groups according to Slug composite score (≤4, 6, and 9). Low, mid, and high expression of Slug was observed in 104 (22.7%), 130 (28.3%), and 225 (49.0%) of cases, respectively. Overall survival and recurrence-free survival progressively increased from high to low Slug expression. In terms of lymph node metastasis, the rate of positive lymph node metastasis was 38/104 (36.5%), 79/130 (60.8%), and 178/225 (79.1%) in low, mid, and high Slug expression groups, respectively, displaying a tendency to increase with higher Slug expression. In a multivariate analysis adjusting for patient age, tumor size, tumor depth, and histology, high Slug expression was associated with a high rate of positive lymph node metastasis compared with low Slug expression (odds ratio 3.42; 95% confidence interval, 1.74-6.69). In a subgroup analysis of T1 cancer, patients with negative Slug expression (defined as <5% positive tumor cells or no/weak staining) showed no lymph node metastasis (0/13), whereas those with positive Slug expression showed 15.9% (17/107) lymph node metastasis, with a negative predictive value of 100%.

CONCLUSIONS

High expression of Slug in gastric cancer tissue was associated with lymph node metastasis and poor survival. Evaluation of Slug would be useful for discriminating patients at high risk of lymph node metastasis in early gastric cancer.

Clinical application of early gastric carcinoma with lymphoid stroma based on lymph node metastasis status

BACKGROUND

Gastric carcinoma with lymphoid stroma (GCLS) is characterized by undifferentiated carcinoma mixed with prominent lymphoid infiltration. GCLS has unique clinicopathological features and a better prognosis compared to other types of gastric cancer. We analyzed the clinicopathological features of early GCLS in relation to lymph node metastasis (LNM).

METHODS

We performed a retrospective analysis of 241 patients diagnosed with GCLS confined to the mucosa or the submucosa between March 1998 and December 2015. Their data were compared with those from 1219 patients who underwent resection for differentiated early gastric cancer (EGC).

RESULTS

Of the 241 patients analyzed, 33 (13.7%) had intramucosal cancers and 208 (86.3%) had cancers that penetrated the submucosa. Compared to differentiated EGC, early GCLS was more prevalent in younger individuals and in men, tended to be proximally located, was highly associated with Epstein-Barr virus (EBV) infection (89.2%), and had a lower risk of LNM. The 5-year disease-specific survival rate of patients with early GCLS was 98.3% but depended significantly on LNM status (p < 0.001) and EBV infection status (p = 0.039). The risk of LNM from mucosal GCLS and submucosal GCLS was 0% [95% confidence interval (CI) 0-9.1] and 10% (95% CI 6.8-15.2), respectively. On multivariate analysis, LNM was found to be associated with tumor size (p = 0.022) and lymphovascular invasion (p = 0.002) in addition to tumor depth.

CONCLUSIONS

Early GCLS has distinct clinicopathological features depending on age, sex, tumor location, EBV infection status, and LNM status. Tailored therapies, including endoscopic treatment, are needed based on the distinct clinicopathological features of early GCLS.

Predictive factors for lymph node metastasis in early gastric cancer with lymphatic invasion after endoscopic resection

BACKGROUND

Lymph node (LN) metastasis is found in only about 5-10% of the patients who undergo additional surgery after non-curative endoscopic resection. Lymphatic invasion after endoscopic submucosal dissection (ESD) is regarded as non-curative resection due to risk of reginal LN metastasis. This study was aimed to identify clinicopathologic predictive factors for LN metastasis in early gastric cancer (EGC) with lymphatic invasion after endoscopic resection.

METHODS

Among a total of 2036 patients who underwent endoscopic resection for EGC at Samsung Medical Center from April 2000 to May 2011, 146 patients were diagnosed with lymphatic invasion. And 123 patients who had gastrectomy with LN dissection due to presence of lymphatic invasion as one of the non-curative factors were included in this study. Demographics, endoscopic tumor findings, histological findings, surgical findings with pathologic reports, and follow-up data were collected from the patient's medical records. Pathological re-evaluation of resected specimens was performed.

RESULTS

Among a total of 123 patients, LN metastases were found in seven patients (5.7%). The univariate analysis revealed that the LN metastasis was significantly more frequent in patients with certain morphology of lymphatic invasion that shows adhesion to endothelium of lymphatic tumor emboli (p = 0.016), higher number of lymphatic tumor emboli in whole section (p < 0.001) and papillary adenocarcinoma component (p = 0.024). In multivariate analysis, the number of lymphatic tumor emboli [OR 93.5, 95% CI (2.62-3330.81)] and the presence of papillary adenocarcinoma component [OR 552.5, 95% CI (1.20-254871.81)] were identified as independent predictors of LN metastasis in patients with lymphatic invasion after endoscopic resection.

CONCLUSIONS

The number of lymphatic tumor emboli and the presence of papillary adenocarcinoma component were significant predictors for LN metastasis in patients with lymphatic invasion after endoscopic resection.

Prediction of lymph node metastasis and sentinel node navigation surgery for patients with early-stage gastric cancer

Accurate prediction of lymph node (LN) status is crucially important for appropriate treatment planning in patients with early gastric cancer (EGC). However, consensus on patient and tumor characteristics associated with LN metastasis are yet to be reached. Through systematic search, we identified several independent variables associated with LN metastasis in EGC, which should be included in future research to assess which of these variables remain as significant predictors of LN metastasis. On the other hand, even if we use these promising parameters, we should realize the limitation and the difficulty of predicting LN metastasis accurately. The sentinel LN (SLN) is defined as first possible site to receive cancer cells along the route of lymphatic drainage from the primary tumor. The absence of metastasis in SLN is believed to correlate with the absence of metastasis in downstream LNs. In this review, we have attempted to focus on several independent parameters which have close relationship between tumor and LN metastasis in EGC. In addition, we evaluated the history of sentinel node navigation surgery and the usefulness for EGC.

A nomogram for predicting the likelihood of lymph node metastasis in early gastric patients

Background

Early gastric cancer is defined as a lesion confined to the mucosa or submucosa, regardless of the size or lymph node metastasis. Treatment methods include endoscopic mucosal resection or endoscopic submucosal dissection, wedge resection, laparoscopically assisted gastrectomy and open gastrectomy. Lymph node metastasis is strong related with survival and recurrence. Therefore, the likelihood of lymph node metastasis is one of the most important factors when determining the most appropriate treatment.

Methods

We retrospectively analyzed 597 patients who underwent D2 gastrectomy for early gastric cancer. The relationship between lymph node metastasis and clinicopathological features was analyzed. Using multivariate logistic regression analyses, we created a nomogram to predict the lymph node metastasis probability for early gastric cancer. Receiver operating characteristic analyses was performed to assess the predictive value of the model.

Results

In the present study, 58 (9.7 %) early gastric cancer patients were histologically shown to have lymph node metastasis. The multivariate logistic regression analysis demonstrated that the age at diagnosis, differentiation status, the presence of ulcers, lymphovascular invasion and depth of invasion were independent risk factors for lymph node metastasis in early gastric cancer. Additionally, the tumor macroscopic type, size and histology type significantly correlated with these important independent factors. We constructed a predictive nomogram with these factors for lymph node metastasis in early gastric cancer patients, and the discrimination was good with the AUC of 0.860 (95 % CI: 0.809–0.912).

Conclusions

We developed an effective nomogram to predict the incidence of lymph node metastasis for early gastric cancer 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.

Nomogram for predicting lymph node metastasis rate of submucosal gastric cancer by analyzing clinicopathological characteristics associated with lymph node metastasis

BACKGROUND

To combine clinicopathological characteristics associated with lymph node metastasis for submucosal gastric cancer into a nomogram.

METHODS

We retrospectively analyzed 262 patients with submucosal gastric cancer who underwent D2 gastrectomy between 1996 and 2012. The relationship between lymph node metastasis and clinicopathological features was statistically analyzed. With multivariate logistic regression analysis, we made a nomogram to predict the possibility of lymph node metastasis. Receiver operating characteristic (ROC) analysis was also performed to assess the predictive value of the model. Discrimination and calibration were performed using internal validation.

RESULTS

A total number of 48 (18.3%) patients with submucosal gastric cancer have pathologically lymph node metastasis. For submucosal gastric carcinoma, lymph node metastasis was associated with age, tumor location, macroscopic type, size, differentiation, histology, the existence of ulcer and lymphovascular invasion in univariate analysis (all P<0.05). The multivariate logistic regression analysis identified that age ≤50 years old, macroscopic type III or mixed, undifferentiated type, and presence of lymphovascular invasion were independent risk factors of lymph node metastasis in submucosal gastric cancer (all P<0.05). We constructed a predicting nomogram with all these factors for lymph node metastasis in submucosal gastric cancer with good discrimination [area under the curve (AUC) =0.844]. Internal validation demonstrated a good discrimination power that the actual probability corresponds closely with the predicted probability.

CONCLUSIONS

We developed a nomogram to predict the rate of lymph node metastasis for submucosal gastric cancer. With good discrimination and internal validation, the nomogram improved individualized predictions for assisting clinicians to make appropriated treatment decision for submucosal gastric cancer patients.

Is It Reasonable to Treat Early Gastric Cancer with Mucosal Infiltration and Well Differentiation by Endoscopic Submucosal Resection?

BACKGROUND

While limited endoscopic submucosal dissection (ESD) is increasingly applied in the treatment of early gastric cancer, preoperative prediction of lymph node metastasis is very critical for determining treatment strategies preoperatively. Thus, the aim of this study was to accurately assess the prevalence and pattern of lymph node metastasis in early gastric cancer patients and to identify the best candidates for ESD.

METHODS

From September 2008 to December 2013, a total of 539 patients with early gastric cancer were retrospectively analyzed in the present study. Of them, 503 patients underwent radical gastrectomy and 36 patients underwent ESD. The clinicopathological features were collected and correlations with lymph node metastasis were analyzed. The survival rates of patients were also analyzed.

RESULTS

Lymph node metastasis was observed in 80 of 503 patients (15.9 %). Among these, the rate for mucosal cancer was 8.3 %, and 20.1 % for submucosal cancer. By univariate analysis, risk factors for lymph node metastasis were growth pattern, tumor size, pathological type, depth of invasion, lymphatic-vascular invasion, and neural invasion. By multivariate analysis, risk factors for lymph node metastasis were tumor size, pathological type, depth of invasion, and lymphatic-vascular invasion. The incidence of lymph node metastasis was 0 % in the well-differentiated mucosal cancers, irrespective of tumor size. For the well-differentiated mucosal cancers, the overall survival rates were comparable between patients underwent gastrectomy with lymph node dissection and patients underwent ESD (100 vs 100 %).

CONCLUSIONS

The most important factors for predicting lymph node metastasis in early gastric cancer are tumor size, pathological type, depth of invasion, and lymphatic-vascular invasion. Well-differentiated mucosal gastric cancers could be candidates for ESD.

Defining a Subgroup Treatable for Laparoscopic and Endoscopic Cooperative Surgery in Undifferentiated Early Gastric Cancer: the Role of Lymph Node Metastasis

BACKGROUND

Recently, the use of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) and the development of laparoscopic and endoscopic cooperative surgery (LECS) have enabled either the preservation of the stomach or the minimization of the extent of partial resection. ESD has recently been practiced on a differentiated type of EGC. However, there is no clear evidence for endoscopic treatments of undifferentiated EGC. The purposes of this study are to investigate predictive factors of lymph node metastasis (LNM) in undifferentiated EGC and expand the possibility of using LECS for the treatment of undifferentiated EGC.

METHODS

Data from 116 patients with undifferentiated EGC and surgically treated were collected, and the association between the clinicopathological factors and the presence of LNM was retrospectively analyzed by univariate and multivariate logistic regression analyses. Odds ratios (OR) with 95 % confidence interval (95 % CI) were calculated.

RESULTS

The tumor size (OR = 11.748, 95 % CI 2.034-62.213, P = 0.008), depth of invasion (OR = 13.928, 95 % CI 1.971-92.434, P = 0.016), and lymphatic vessel involvement (OR = 11.522, 95 % CI 2.645-59.172, P = 0.021) that were significantly associated with LNM by univariate analysis were found to be significant and independent risk factors for LNM by multivariate analysis. The LNM rate was 5.9 % (4/68) and 29.2 % (14/48) with intramucosal and submucosal undifferentiated EGC, respectively. LNM was observed in 66.7 % (2/3) of patients with both risk factors (tumor larger than or equal to 2.0 cm and the presence of lymphatic vessel involvement (LVI)), but in none of 36 patients without the two risk factors in intramucosal undifferentiated EGC. The 5-year survival rates were 88.9, 72.4, and 33.3 %, respectively, in cases with none, one, and two of the risk factors, respectively, in intramucosal undifferentiated EGC (P < 0.05).

CONCLUSIONS

ESD alone may be a sufficient treatment for intramucosal undifferentiated EGC if the tumor is less than 2.0 cm in size and when LVI is absent upon postoperative histological examination. LECS is feasible and safe for patients with undifferentiated EGC.

Differences in Clinicopathology of Early Gastric Carcinoma between Proximal and Distal Location in 438 Chinese Patients

Early gastric carcinoma (EGC) in Chinese patients remains poorly understood and endoscopic therapy has not been well established. Here, we compared endoscopic and clinicopathologic features between early proximal gastric carcinoma (PGC, n = 131) and distal gastric carcinoma (DGC, n = 307) in consecutive 438 EGCs diagnosed with the WHO criteria. By endoscopy, PGCs showed protruding and elevated patterns in 61.9%, while depressed and excavated patterns in 33.6%, which were significantly different from those (32.6% and 64.5%) in DGCs. PGCs were significantly smaller (1.9 cm in average, versus 2.2 cm in DGCs), invaded deeper (22.9% into SM2, versus 13% in DGCs), but had fewer (2.9%, versus 16.7% in DGCs) lymph node metastases. Papillary adenocarcinoma was significantly more frequent (32.1%, versus 12.1% in DGCs), as were mucinous and neuroendocrine carcinomas, carcinoma with lymphoid stroma (6.9%, versus 1.6% in DGCs); but poorly cohesive carcinoma was significantly less frequent (5.3%, versus 35.8% in DGCs). The overall 5-year survival rate was 92.9% in EGCs, and PGC patients showed shorter (42.4 months, versus 48.3 in DGCs) survival. Papillary and micropapillary adenocarcinomas and nodal metastasis were independent risk factors for worse survival in EGCs. EGCs in Chinese were heterogeneous with significant differences in endoscopy and clinicopathology between PGC and DGC.

A multicenter study of using carbon nanoparticles to show sentinel lymph nodes in early gastric cancer

BACKGROUND

Lymph node metastasis occurs in approximately 10% of early gastric cancer. Preoperative or intra-operative identification of lymph node metastasis in early gastric cancer is crucial for surgical planning. The purpose of this study was to evaluate the feasibility of using carbon nanoparticles to show sentinel lymph nodes (SLNs) in early gastric cancer.

METHODS

A multicenter study was performed between July 2012 and November 2014. Ninety-one patients with early gastric cancer identified by preoperative endoscopic ultrasonography were recruited. One milliliter carbon nanoparticles suspension, which is approved by Chinese Food and Drug Administration, was endoscopically injected into the submucosal layer at four points around the site of the primary tumor 6-12 h before surgery. Laparoscopic radical resection with D2 lymphadenectomy was performed. SLNs were defined as nodes that were black-dyed by carbon nanoparticles in greater omentum and lesser omentum near gastric cancer. Lymph node status and SLNs accuracy were confirmed by pathological analysis.

RESULTS

All patients had black-dyed SLNs lying in greater omentum and/or lesser omentum. SLNs were easily found under laparoscopy. The mean number of SLNs was 4 (range 1-9). Carbon nanoparticles were around cancer in specimen. After pathological analysis, 10 patients (10.99%) had lymph node metastasis in 91 patients with early gastric cancer. SLNs were positive in 9 cases and negative in 82 cases. In pathology, carbon nanoparticles were seen in lymphatic vessels, lymphoid sinus, and macrophages in SLNs. When SLNs were positive, cancer cells were seen in lymph nodes. The sensitivity, specificity, and accuracy of black-dyed SLNs in early gastric cancers were 90, 100, and 98.9 %, respectively. No patient had any side effects of carbon nanoparticles in this study.

CONCLUSIONS

It is feasible to use carbon nanoparticles to show SLNs in early gastric cancer. Carbon nanoparticles suspension is safe for submucosal injection.

Endoscopic submucosal dissection for undifferentiated-type early gastric cancer: do we have enough data to support this?

Although endoscopic submucosal dissection (ESD) is now accepted for treatment of early gastric cancers (EGC) with negligible risk of lymph node (LN) metastasis, ESD for intramucosal undifferentiated type EGC without ulceration and with diameter ≤ 2 cm is regarded as an investigational treatment according to the Japanese gastric cancer treatment guidelines. This consideration was largely based on the analysis of surgically resected EGCs that contained undifferentiated type EGCs; however, results from several institutes showed some discrepancies in sample size and incidence of LN metastasis. Recently, some reports about the safety and efficacy of ESD for undifferentiated type EGC meeting the expanded criteria have been published. Nonetheless, only limited data are available regarding long-term outcomes of ESD for EGC with undifferentiated histology so far. At the same time, endoscopists cannot ignore the patients' desire to guarantee quality of life after the relatively non-invasive endoscopic treatment when compared to conventional surgery. To satisfy the needs of patients and provide solid evidence to support ESD for undifferentiated EGC, we need more delicate tools to predict undetected LN metastasis and more data that can reveal predictive factors for LN metastasis.

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.

[Synopsis on clinical practice guideline of gastric cancer in Korea: an evidence-based approach]

Although, gastric cancer is quite common in Korea, the treatment outcome is relatively favorable compared to that of Western countries. However, there is no Korean multidisciplinary guideline for gastric cancer and thus, a guideline adequate for domestic circumstances is required. Experts from related societies developed 22 recommendation statements for the diagnosis (n=9) and treatment (n=13) based on relevant key questions. Evidence levels based on systematic review of literatures were classified as five levels from A to E, and recommendation grades were classified as either strong or weak. The topics of this guideline cover diagnostic modalities (endoscopy, endoscopic ultrasound, radiologic diagnosis), treatment modalities (surgery, therapeutic endoscopy, chemotherapy, radiotherapy) and pathologic evaluation. External review of the guideline was conducted at the finalization phase.

Clinical practice guidelines for gastric cancer in Korea: an evidence-based approach

Although gastric cancer is quite common in Korea, the treatment outcome is relatively favorable compared to those in western countries. However, there are currently no Korean multidisciplinary guidelines for gastric cancer. Experts from related societies developed guidelines de novo to meet Korean circumstances and requirements, including 23 recommendation statements for diagnosis (n=9) and treatment (n=14) based on relevant key questions. The quality of the evidence was rated according to the GRADE evidence evaluation framework: the evidence levels were based on a systematic review of the literature, and the recommendation grades were classified as either strong or weak. The applicability of the guidelines was considered to meet patients' view and preferences in the context of Korea. The topics of the guidelines cover diagnostic modalities (endoscopy, endoscopic ultrasound, and radiologic diagnosis), treatment modalities (surgery, therapeutic endoscopy, chemotherapy, and radiotherapy), and pathologic evaluation. An external review of the guidelines was conducted during the finalization phase.

State-of-the-art preoperative staging of gastric cancer by MDCT and magnetic resonance imaging

Gastric cancer is one of the most common and fatal cancers. The importance of accurate staging for gastric cancer has become more critical due to the recent introduction of less invasive treatment options, such as endoscopic mucosal resection or laparoscopic surgery. The tumor-node-metastasis staging system is the generally accepted staging system for predicting the prognosis of patients with gastric cancer. Multidetector row computed tomography (MDCT) is a widely accepted imaging modality for the preoperative staging of gastric cancer that can simultaneously assess locoregional staging, including the gastric mass, regional lymph nodes, and distant metastasis. The diagnostic performance of MDCT for T- and N-staging has been improved by the technical development of isotropic imaging and 3D reformation. Although magnetic resonance imaging (MRI) was not previously used to evaluate gastric cancer due to the modality’s limitations, the development of high-speed sequences has made MRI a feasible tool for the staging of gastric cancer.

Endoscopic submucosal dissection for undifferentiated-type early gastric cancer: Do we have enough data to support this?

Although endoscopic submucosal dissection (ESD) is now accepted for treatment of early gastric cancers (EGC) with negligible risk of lymph node (LN) metastasis, ESD for intramucosal undifferentiated type EGC without ulceration and with diameter ≤ 2 cm is regarded as an investigational treatment according to the Japanese gastric cancer treatment guidelines. This consideration was largely based on the analysis of surgically resected EGCs that contained undifferentiated type EGCs; however, results from several institutes showed some discrepancies in sample size and incidence of LN metastasis. Recently, some reports about the safety and efficacy of ESD for undifferentiated type EGC meeting the expanded criteria have been published. Nonetheless, only limited data are available regarding long-term outcomes of ESD for EGC with undifferentiated histology so far. At the same time, endoscopists cannot ignore the patients’ desire to guarantee quality of life after the relatively non-invasive endoscopic treatment when compared to conventional surgery. To satisfy the needs of patients and provide solid evidence to support ESD for undifferentiated EGC, we need more delicate tools to predict undetected LN metastasis and more data that can reveal predictive factors for LN metastasis.

Temporal evolution of multidetector CT findings after endoscopic submucosal dissection in patients with early gastric cancer: correlation with endoscopy

OBJECTIVE

To assess changes over time in imaging findings retrospectively by multidetector CT (MDCT) with two-dimensional (2D) multiplanar reconstruction and three-dimensional (3D) CT gastrography (CTG), after endoscopic submucosal dissection (ESD) in patients with early gastric cancer (EGC), and to correlate 3D CT images with endoscopic appearance.

MATERIALS AND METHODS

In this retrospective study, a total of 84 patients underwent ESD and were followed up with MDCT. Fifteen patients underwent CT twice, and 3 patients underwent CT 3 times. A total of 105 CTs were included in this study and 43 CTs contained 3D CTGs. Two radiologists in consensus interpreted CT images for lesion detectability, presence and characteristics of ulcer, focal wall thickening, perigastric fat infiltration, and overlying enhancing layer in 2D images. The presence of ulcer or subtle mucosal nodularity, ulcer mound, and fold convergence were analysed in 3D CT images. We also assessed the time interval between ESD and CT and analysed the temporal evolution of CT findings. The sensitivity, specificity, and overall accuracy of 3D CTG were assessed regarding endoscopic features as the gold standard.

RESULTS

The mean interval between ESD and follow up CT was 76.9 days (median, 62; range, 2-223). No tumour recurrence in any lesion was found on follow-up endoscopic biopsy and also lymph node or distant metastasis was not observed on CT exams in the follow-up period. The lesion detectability in a total of 105 post-ESD 2D CT images was 42.0% (44/105), and 93.2% (41/44) of the detected lesions were visualizable 2 months after ESD. Focal wall thickening was observed during the entire follow-up period in all patients. Perigastric fat infiltration was observed in 4 lesions within 1 week of ESD. Overlying enhancing layer appeared in 27 lesions without temporal evolution. On a total of 43 post-ESD 3D CTG, lesion detectability was 76.7% (33/43), and lesions could be visualized for a longer period than by 2D CT images (223 days versus 99 days). Three-dimensional imaging features revealed ulcer, ulcer mound, and fold convergence. Ulcer mounds disappeared first (median, 12.5 days; range, 2-14 days after ESD), ulcers appeared up to 4 months after ESD (median, 14 days; range, 2-174 days after ESD) and fold convergence continued to the end of the study (median, 74 days; range, 2-223 days after ESD). We found that sensitivity, specificity, and overall accuracy of 3D CTG were 70.0%, 92.9%, 83.3% for ulcer, 28.6%, 100%, 71.4% for ulcer mound, and 71.4%, 100%, 75% for fold convergence regarding endoscopy, respectively.

CONCLUSION

On follow-up 2D or 3D CT images after ESD, early findings were of perigastric fat infiltration, ulcer, and surrounding oedema. Focal wall thickening and fold convergence continued to be observed late in the study. The overlying enhancing layer did not show temporal evolution.

Usefulness of magnifying endoscopy with narrow-band imaging for diagnosis of depressed gastric lesions

The usefulness of magnifying endoscopy with narrow-band imaging (ME-NBI) for the diagnosis of early gastric cancer is well known, however, there are no evaluation criteria. The aim of this study was to devise and evaluate a novel diagnostic algorithm for ME-NBI in depressed early gastric cancer. Between August, 2007 and May, 2011, 90 patients with a total of 110 depressed gastric lesions were enrolled in the study. A diagnostic algorithm was devised based on ME-NBI microvascular findings: microvascular irregularity and abnormal microvascular patterns (fine network, corkscrew and unclassified patterns). The diagnostic efficiency of the algorithm for gastric cancer and histological grade was assessed by measuring its mean sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. Furthermore, inter- and intra-observer variation were measured. In the differential diagnosis of gastric cancer from non-cancerous lesions, the mean sensitivity, specificity, PPV, NPV, and accuracy of the diagnostic algorithm were 86.7, 48.0, 94.4, 26.7, and 83.2%, respectively. Furthermore, in the differential diagnosis of undifferentiated adenocarcinoma from differentiated adenocarcinoma, the mean sensitivity, specificity, PPV, NPV, and accuracy of the diagnostic algorithm were 61.6, 86.3, 69.0, 84.8, and 79.1%, respectively. For the ME-NBI final diagnosis using this algorithm, the mean κ values for inter- and intra-observer agreement were 0.50 and 0.77, respectively. In conclusion, the diagnostic algorithm based on ME-NBI microvascular findings was convenient and had high diagnostic accuracy, reliability and reproducibility in the differential diagnosis of depressed gastric lesions.

Minimally invasive surgery for serosa-positive gastric cancer (pT4a) in patients with preoperative diagnosis of cancer without serosal invasion

BACKGROUND

Although surgeons normally use minimally invasive surgery (MIS) for patients with early gastric cancer, in Korea and Japan the procedure is also indicated for serosa-negative tumors. Serosal invasion is regarded to be a potential risk factor for peritoneal dissemination as a result of the effect of pneumoperitoneum and tumor manipulation during the operation. We compared operative outcomes between MIS and conventional open surgery for serosa-involved advanced gastric cancer patients who had a preoperative diagnosis of cancer without serosal invasion.

METHODS

A total of 61 patients (39 patients treated by MIS and 22 by open surgery) treated between 2003 and 2009 who were first diagnosed preoperatively as serosa negative on the basis of computed tomography, endoscopy, and endoscopic ultrasound but then diagnosed as serosa positive upon final pathology were studied. We retrospectively compared recurrence and survival between the two treatment groups.

RESULTS

Clinicopathologic characteristics, clinical stage, extent of surgery, and short-term operative outcome did not differ between the groups. 5-year overall survival (73.5 vs. 67.5 %, p = 0.518, respectively) and disease-free survival (67.8 vs. 54.2 %, p = 0.296, respectively) were comparable between the MIS and open surgery groups. There were recurrences in 12 patients in the MIS group and 11 patients in the open surgery group, with a median follow-up period of 64 months. Recurrence patterns did not differ between the groups; moreover, MIS did not increase peritoneal recurrences compared to open surgery (42.0 vs. 54.5 %, p = 0.537, respectively). In multivariate analyses, the type of surgery was not an independent prognostic factor.

CONCLUSIONS

Similar survival and recurrence patterns were observed in advanced gastric cancer patients preoperatively diagnosed as serosa negative who were treated either by MIS or open surgery. MIS may be safely applied in patients with serosa-positive tumors.

The role of 2-[f-18] fluoro 2-deoxy d-glucose positron emission tomography in the preoperative staging of gastric cancer

OBJECTIVE

FDG-PET can contribute significantly to the preoperative period of patients with planned curative resections or with isolated liver or lung metastasis. In this study, we analyze the importance and diagnostic value of FDG-PET in the preoperative evaluation of gastric cancers by correlating its value with computerized tomography (CT).

MATERIALS AND METHODS

A prospective study was conducted. Abdominal and pelvic CTs were obtained for preoperative staging in each patient. Separate stagings were performed according to the findings of conventional methods and PET scans, and the results were compared with the operative and histological findings.

RESULTS

When the patients were evaluated according to the pathological stage, eight patients were Stage 1 (26.7%), five were Stage 2 (16.7%), eight were Stage 3 (26.7%), and nine were Stage 4 (30%). FDG-PET and CT down-staged the disease in eight (26.7%) and twelve (40%) patients, respectively. FDG-PET and CT up-staged the disease in two (6.7%) and five patients (16.7%), respectively. FDG-PET accurately staged the disease in eighteen patients (60%) (p= 0.182).

CONCLUSION

To develop highly sensitive radioactive tests that show invasive local lymph node and peritoneal metastases, more studies in the preoperative staging of gastric cancer are needed. FDG-PET indicates a high specificity in the staging of gastric cancer. In patients who are planned for curative surgery, FDG-PET provides better staging when used with CT.

Assessment of vascular invasion in gastric cancer: A comparative study

AIM: To evaluate and compare detection of lymphatic and blood vessel invasion (LVI and BVI) by hematoxylin-eosin (HE) and immunohistochemistry (IHC) in gastric cancer specimens, and to correlate with lymph node status.

METHODS: IHC using D2-40 (a lymphatic endothelial marker) and CD34 (a pan-endothelial marker) was performed to study LVI and BVI in surgical specimens from a consecutive series of 95 primary gastric cancer cases. The results of the IHC study were compared with the detection by HE using McNemar test and kappa index. The morphologic features of the tumors and the presence of LVI and BVI were related to the presence of lymph node metastasis. A χ² test was performed to obtain associations between LVI and BVI and other prognostic factors for gastric cancer.

RESULTS: The detection rate of LVI was considerably higher than that of BVI. The IHC study identified eight false-positive cases and 13 false-negative cases for LVI, and 24 false-positive cases and 10 false-negative cases for BVI. The average Kappa value determined was moderate for LVI (κ = 0.50) and low for BVI (κ = 0.20). Both LVI and BVI were statistically associated with the presence of lymph node metastasis (HE: P = 0.001, P = 0.013, and IHC: P = 0.001, P = 0.019). The morphologic features associated with LVI were location of the tumor in the distal third of the stomach (P = 0.039), Borrmann’s macroscopic type (P = 0.001), organ invasion (P = 0.03) and the depth of tumor invasion (P = 0.001). The presence of BVI was related only to the depth of tumor invasion (P = 0.003).

CONCLUSION: The immunohistochemical identification of lymphatic and blood vessels is useful for increasing the accuracy of the diagnosis of vessel invasion and for predicting lymph node metastasis.

Prediction of risk factors for lymph node metastasis in early gastric cancer

AIM: To explore risk factors for lymph node metastases in early gastric cancer (EGC) and to confirm the appropriate range of lymph node dissection.

METHODS: A total of 202 patients with EGC who underwent curative gastrectomy with lymphadenectomy in the Department of Surgery, Xinhua Hospital and Ruijin Hospital of Shanghai Jiaotong University Medical School between November 2003 and July 2009, were retrospectively reviewed. Both the surgical procedure and the extent of lymph node dissection were based on the recommendations of the Japanese gastric cancer treatment guidelines. The macroscopic type was classified as elevated (type I or IIa), flat (IIb), or depressed (IIc or III). Histopathologically, papillary and tubular adenocarcinomas were grouped together as differentiated adenocarcinomas, and poorly differentiated and signet-ring cell adenocarcinomas were regarded as undifferentiated adenocarcinomas. Univariate and multivariate analyses of lymph node metastases and patient and tumor characteristics were undertaken.

RESULTS: The lymph node metastases rate in patients with EGC was 14.4%. Among these, the rate for mucosal cancer was 5.4%, and 8.9% for submucosal cancer. Univariate analysis showed an obvious correlation between lymph node metastases and tumor location, depth of invasion, morphological classification and venous invasion (χ² = 122.901, P = 0.001; χ² = 7.14, P = 0.008; χ² = 79.523, P = 0.001; χ² = 8.687, P = 0.003, respectively). In patients with submucosal cancers, the lymph node metastases rate in patients with venous invasion (60%, 3/5) was higher than in those without invasion (20%, 15/75) (χ² = 4.301, P = 0.038). Multivariate logistic regression analysis revealed that the depth of invasion was the only independent risk factor for lymph node metastases in EGC [P = 0.018, Exp (B) = 2.744]. Among the patients with lymph node metastases, 29 cases (14.4%) were at N1, seven cases were at N2 (3.5%), and two cases were at N3 (1.0%). Univariate analysis of variance revealed a close relationship between the depth of invasion and lymph node metastases at pN₁ (P = 0.008).

CONCLUSION: The depth of invasion was the only independent risk factor for lymph node metastases. Risk factors for metastases should be considered when choosing surgery for EGC.

Clinical implication of endoscopic gross appearance in early gastric cancer: revisited

BACKGROUND

The macroscopic appearance of early gastric cancer (EGC) is known to reflect its growth patterns. The purpose of this study was to investigate the role of the endoscopic appearance as a predictor of clinical behavior in EGC.

METHODS

Between January 2005 and December 2008, 1,845 patients were diagnosed with EGC and underwent surgery. The clinicopathologic characteristics were retrospectively analyzed according to gross appearance. Endoscopic findings were classified by predominant type as elevated, flat, or depressed. Flat and depressed types were categorized together as nonelevated type.

RESULTS

The proportions of elevated, flat, and depressed types were 16.6, 28.6, and 54.8 %. The gross appearance of the elevated type predominantly showed well/moderate differentiation, whereas the flat and depressed types showed signet-ring cells and poor differentiation, respectively. When the elevated and nonelevated types were compared, submucosal invasion, lymphovascular invasion (LVI), and lymph-node metastasis (LNM) were higher in elevated than in nonelevated type. In differentiated EGC, submucosal invasion, LVI, LNM, and multiplicity were significantly higher in the elevated than the nonelevated type. These patterns were significantly common in the order elevated, depressed, and flat types. In undifferentiated EGC, submucosal invasion, LVI, and perineural invasion were significantly higher in elevated than in nonelevated type. These patterns were significantly common in the order elevated, depressed, and flat types. However, LNM was not significantly different based on gross appearance in undifferentiated EGC.

CONCLUSIONS

Clinical behavior differs according to endoscopic appearance in EGC. The endoscopic appearance of EGC may facilitate prediction of clinical behavior, particularly in differentiated EGC.

The risk factors for lymph node metastasis in early gastric cancer patients who underwent endoscopic resection: is the minimal lymph node dissection applicable? A retrospective study

PURPOSE

The purpose of this study was to identify risk factors associated with lymph node (LN) metastasis in early gastric cancer patients who underwent endoscopic resection (ER) and to evaluate the feasibility of minimal LN dissection in these patients.

METHODS

From January 2001 to March 2011, patients who underwent gastrectomy with lymphadenectomy due to the potential risk of LN metastasis after ER were enrolled at National Cancer Center, Korea. The incidence, risk factors, and distribution of LN metastasis were evaluated.

RESULTS

Of the 147 enrolled patients, the LN metastasis was identified in 12 patients (8.2%). The incidence of LN metastasis was not significantly increased in patients with submucosal invasion, lymphovascular invasion, and mixed undifferentiated histology [odds ratio (OR), 5.55, 1.349, and 0.387; 95% confidence interval (CI), 0.688-43.943, 0.405-4.494, and 0.081-1.84, respectively]. Tumor size more than 2 cm was significantly associated with LN metastasis (OR, 14.056; 95% CI, 1.76-112.267). The incidence of LN metastasis gradually increased from 3.2 to 20%, as number of risk factors increased (P = 0.019). LN metastasis was present primarily along the perigastric area in all except two patients (1.4%) with skip metastasis to extragastric area.

CONCLUSIONS

Standard surgery with at least D1 + LN dissection must be recommended for patients who proved to have risk factors for LN metastasis after ER, because the potential of skip metastasis is not negligible. Nevertheless, the minimal LN dissection, such as sentinel basin dissection, might be applied cautiously in patients with small-sized tumors after ER.

Endoscopic holmium:YAG laser ablation of early gastrointestinal intramucosal cancer

Various endoscopic techniques are being increasingly used in early gastrointestinal (GI) cancer. The holmium: yttrium-aluminum-garnet (Ho:YAG) laser has precise tissue cutting ability and good hemostatic properties and has been widely applicated to soft tissue, but the use of endoscopic Ho:YAG laser ablation for early gastrointestinal cancer has not been reported. Twenty patients with biopsy-proven early GI cancer who had a high surgical risk or refused surgery were treated by endoscopic Ho:YAG laser ablation. The tumors of all patients were confined to the mucosal layer without ulceration and without lymph node metastasis. The tumor diameter was not more than 2.5 cm. Endoscopy, endoscopic ultrasound, and computed tomography scan were performed 1-3 months after the treatment, and a biopsy was performed to evaluate the effects of the therapy. Long-term endoscopic follow-up was maintained. Complete eradication was achieved in all the 20 patients, including four patients with high-grade dysplasia associated with focal canceration, seven patients with well-differentiated squamous cell cancer, and nine patients with well-differentiated adenocarcinoma, resulting in a complete response rate of 100% at 1-3 months after treatment. No recurrence was found during 36-73 months of follow-up in all 20 patients. No operative or delayed complications were observed in any of the 20 patients. Preliminary study shows that endoscopic Ho:YAG laser ablation may be an effective, safe, and minimally invasive method for selected patients with early GI intramucosal cancer. Further research is required to confirm the safety and efficacy of this technique compared to its alternative techniques in a multicenter randomized controlled trial.

Risk clinicopathological factors for lymph node metastasis in poorly differentiated early gastric cancer and their impact on laparoscopic wedge resection

AIM: To investigate the predictive factors of lymph node metastasis (LNM) in poorly differentiated early gastric cancer (EGC), and enlarge the possibility of using laparoscopic wedge resection (LWR).

METHODS: We retrospectively analyzed 85 patients with poorly differentiated EGC who underwent surgical resection between January 1992 and December 2010. The association between the clinicopathological factors and the presence of LNM was retrospectively analyzed by univariate and multivariate logistic regression analyses. Odds ratios (OR) with 95%CI were calculated. We further examined the relationship between the positive number of the three significant predictive factors and the LNM rate.

RESULTS: In the univariate analysis, tumor size (P = 0.011), depth of invasion (P = 0.007) and lymphatic vessel involvement (P < 0.001) were significantly associated with a higher rate of LNM. In the multivariate model, tumor size (OR = 7.125, 95%CI: 1.251-38.218, P = 0.041), depth of invasion (OR = 16.624, 95%CI: 1.571-82.134, P = 0.036) and lymphatic vessel involvement (OR = 39.112, 95%CI: 1.745-123.671, P = 0.011) were found to be independently risk clinicopathological factors for LNM. Of the 85 patients diagnosed with poorly differentiated EGC, 12 (14.1%) had LNM. The LNM rates were 5.7%, 42.9% and 57.1%, respectively in cases with one, two and three of the risk factors respectively in poorly differentiated EGC. There was no LNM in 29 patients without the three risk clinicopathological factors.

CONCLUSION: LWR alone may be sufficient treatment for intramucosal poorly differentiated EGC if the tumor is less than or equal to 2.0 cm in size, and when lymphatic vessel involvement is absent at postoperative histological examination.

Predictive factors for lymph node metastasis in patients with poorly differentiated early gastric cancer

BACKGROUND

Endoscopic submucosal dissection is gaining popularity in the treatment of early gastric cancer. This study aimed to identify clinicopathological factors predictive of lymph node metastasis in patients with the poorly differentiated early gastric cancer to assess the feasibility of using endoscopic submucosal dissection for these cancers.

METHODS

The records of patients with poorly differentiated early gastric cancer who had undergone gastric cancer surgery between January 2002 and December 2009 were reviewed. Associations between clinicopathological factors and the presence of lymph node metastasis were analysed by univariable and multivariable logistic regression analysis.

RESULTS

Some 1005 patients were included in the analysis. Univariable analysis indicated that lymph node metastasis was associated with sex, ulceration, tumour size, depth of invasion, macroscopic type, lymphatic invasion and venous invasion. Logistic regression revealed that lymph node metastasis was significantly associated with sex, tumour size, depth of tumour invasion and lymphatic involvement. In the group with none of these risk factors (men with mucosal tumour no larger than 2 cm in size, with no lymphatic involvement), lymph node metastasis was present in four (3·2 per cent) of 124 patients.

CONCLUSION

In the present study 3·2 per cent of patients who were negative for all identified risk factors had lymph node metastasis. The use of endoscopic submucosal dissection should be considered carefully in the treatment of poorly differentiated early gastric cancer.

A case of metastatic leptomeningeal carcinomatosis from early gastric carcinoma

Metastatic leptomeningeal carcinomatosis is estimated to occur in 3% to 8% of solid carcinomas. The most common causes of leptomeningeal carcinomatosis are breast cancer, lung cancer and malignant melanoma. Leptomeningeal carcinomatosis associated with gastric cancer, especially in its early stages, is exceedingly rare. Its presenting symptoms include headache, nauseaand seizures. In this report, we describe a case of leptomeningeal metastasis that presented with early-stage gastric cancer. A 67-year-old woman with a history of early-stage gastric cancer in remission was admitted to our hospital with 3 days of headache and nausea. Her gastric cancer had been treated 29 months prior to presentation by a radical subtotal gastrectomy with a Billroth I anastomosis. She had an uneventful recovery until she was diagnosed with metastases to the left axilla and neck 26 months after surgery. Her presenting symptoms of headache and nausea prompted cytologic examination of the cerebrospinal fluid and measurement of tumor markers, which revealed metastatic leptomeningeal carcinomatosis from her gastric cancer. This report aims to raise awareness of the possibility that even early-stage gastric cancer can lead to leptomeningeal carcinomatosis.