Early gastric carcinoma with special reference to macroscopic classification

Application of machine learning algorithm in predicting distant metastasis of T1 gastric cancer

Distant metastasis (DM) is relatively uncommon in T1 stage gastric cancer (GC). The aim of this study was to develop and validate a predictive model for DM in stage T1 GC using machine learning (ML) algorithms. Patients with stage T1 GC from 2010 to 2017 were screened from the public Surveillance, Epidemiology and End Results (SEER) database. Meanwhile, we collected patients with stage T1 GC admitted to the Department of Gastrointestinal Surgery of the Second Affiliated Hospital of Nanchang University from 2015 to 2017. We applied seven ML algorithms: logistic regression, random forest (RF), LASSO, support vector machine, k-Nearest Neighbor, Naive Bayesian Model, Artificial Neural Network. Finally, a RF model for DM of T1 GC was developed. The AUC, sensitivity, specificity, F1-score and accuracy were used to evaluate and compare the predictive performance of the RF model with other models. Finally, we performed a prognostic analysis of patients who developed distant metastases. Independent risk factors for prognosis were analysed by univariate and multifactorial regression. K-M curves were used to express differences in survival prognosis for each variable and subvariable. A total of 2698 cases were included in the SEER dataset, 314 with DM, and 107 hospital patients were included, 14 with DM. Age, T-stage, N-stage, tumour size, grade and tumour location were independent risk factors for the development of DM in stage T1 GC. A combined analysis of seven ML algorithms in the training and test sets found that the RF prediction model had the best prediction performance (AUC: 0.941, Accuracy: 0.917, Recall: 0.841, Specificity: 0.927, F1-score: 0.877). The external validation set ROCAUC was 0.750. Meanwhile, survival prognostic analysis showed that surgery (HR = 3.620, 95% CI 2.164-6.065) and adjuvant chemotherapy (HR = 2.637, 95% CI 2.067-3.365) were independent risk factors for survival prognosis in patients with DM from stage T1 GC. Age, T-stage, N-stage, tumour size, grade and tumour location were independent risk factors for the development of DM in stage T1 GC. ML algorithms had shown that RF prediction models had the best predictive efficacy to accurately screen at-risk populations for further clinical screening for metastases. At the same time, aggressive surgery and adjuvant chemotherapy can improve the survival rate of patients with DM.

Fifty years of digestive endoscopy: Successes, setbacks, solutions and the future

Flexible endoscopes became generally available 50 years ago and created a revolution in the practice of gastroenterology. They improved diagnosis enormously, enabled quicker, less invasive, and more cost-effective surgical treatment, while endoscopic screening has prevented many cancer deaths. The new technology stimulated research leading to a better understanding of gastrointestinal pathology, identifying new diseases and clarifying the etiology of others. Better-controlled clinical trials accelerated the use of newer and more effective drugs. National and international endoscopy societies supported nursing input, encouraged research, stimulated specialist journals, and devised guidelines that encouraged audit and quality assurance. Advances in instrument design and the manufacture of new accessories enhanced endoscopic technique, diagnostic ability, patient comfort, and safety. The risk of cross-infection inherent in the use of complex labile equipment that cannot be autoclaved remains a challenge. Endoscopy societies working closely with industry have established rigid protocols for high-level disinfection that minimize the risks, but strict adherence to guidelines and continued vigilance is essential, especially with the increasing prevalence of antibiotic-resistant commensals that can give rise to opportunistic infection. Government health departments have a responsibility to encourage and support research in this area by endoscopists, instrument manufacturers, and the pharmaceutical industry. Current trends suggest that in the future, artificial intelligence will greatly improve endoscopic diagnosis, and that therapeutic endoscopy will expand, encouraging endoscopists to subspecialize.

Expression of Oncostatin M in Early Gastric Cancer and Precancerous Lesions

Objective

To detect the expression of the Oncostatin M (OSM) gene and encoded protein in the mucosal epithelium of chronic gastritis, intestinal metaplasia (IM), low-grade intraepithelial neoplasia (LGIN), high-grade intraepithelial neoplasia (HGIN), early gastric cancer (EGC), and advanced gastric cancer (AGC) samples and to explore the correlation and clinicopathological significance of OSM expression in the process of gastric carcinogenesis.

Methods

The expression levels of OSM in chronic gastritis, IM, LGIN, HGIN, EGC, and AGC samples were detected by gene chip, real-time quantitative PCR, and immunohistochemical methods. The expression levels of OSM in the gastric mucosa were analyzed, and its correlation with clinical pathology was studied.

Results

The expression level of OSM in gastric HGIN and EGC tissues was significantly higher than that in LGIN tissues based on expression profiling (P < 0.001). The expression of the OSM gene in EGC was higher than that in HGIN (unpaired t test, P < 0.05) and LGIN (unpaired t test, P < 0.01) by qPCR. The expression of OSM in LGIN was significantly lower than that in HGIN (P = 0.008) and EGC (P = 0.044) by immunohistochemical staining. The expression of OSM in HGIN tissues was significantly higher than that in AGC (P = 0.007).

Conclusion

Alterations in the expression of the OSM gene may be involved in the malignant transformation of the gastric mucosal epithelium. Because of the significant difference in the cancerization rate and clinical management between LGIN and HGIN, the difference in the staining intensity of OSM between LGIN and HGIN may be one of the early markers of gastric intraepithelial neoplasia.

Validation of classic and expanded criteria for endoscopic submucosal dissection of early gastric cancer: 7 years of experience in a Western tertiary cancer center

OBJECTIVE

Our aim was to evaluate the Japan Gastroenterological Endoscopy Society criteria for endoscopic submucosal resection of early gastric cancer (EGC) based on the experience in a Brazilian cancer center.

METHODS

We included all patients who underwent endoscopic submucosal resection for gastric lesions between February 2009 and October 2016. Demographic data and information regarding the endoscopic resection, pathological report and follow-up were obtained. Statistical calculations were performed with Fisher's exact test and chi-square tests, with 95% confidence intervals.

RESULTS

In total, 76% of the 51 lesions were adenocarcinomas, 16% were adenomas, and 8% had other diagnoses. The average size was 19.9 mm (±11.7). The average procedure length was 113.9 minutes (±71.4). The complication rate was 21.3%, with only one patient who needed surgical treatment (transmural perforation). Among the adenocarcinomas, 39.5% met the classic criteria for curability, 31.6% met the expanded criteria and 28.9% met the criteria for noncurative resection. Analysis of the indication criteria and curability revealed differences among cases with "only-by-size" expanded criteria (64.28%), other expanded criteria (40%) and classic criteria (89.47%), with a p-value of 0.049. During follow-up (15.8 months; ±14.3), 86.1% of the EGC patients had no recurrence. When well-differentiated and poorly differentiated lesions or lesions included in the classic and expanded criteria were compared, there were no differences in recurrence. The noncurative group presented a higher recurrence rate than the classic group (p=0.014).

CONCLUSION

These results suggest that the Japanese endoscopic submucosal resection criteria might be useful for endoscopic treatment of EGC in Western countries.

An aggressive early gastric cancer: Kodama's PenA type

BACKGROUND

To investigate the role of Kodama PenA subtype in influencing survival in patients with early gastric cancer (EGC).

METHODS

All patients surgically treated for EGC at 7 Italian centers (Forlì, Varese, Siena, Verona, Milan, Rome and Perugia) belonging to the Italian Research Group for Gastric Cancer (GIRCG) from January 1982 and December 2009 were included.

RESULTS

PenA patients were 230 (21.5%) while other types were 839 (78.5%). Nodal metastases were more common in PenA (30.7%) than non-PenA (10.4%) EGCs. Among preoperative variables, only age (OR 1.02; 95% CI 1.00-1.03, p = 0.009) and macrotype III (OR 1.95; 95% CI 1.39-2.75, p = 0.0001) were significantly associated with Pen A type. Survival analysis performed on N0 patients demonstrated that only size >2 cm (HR 1.85; 95% CI 1.12-3.05, p = 0.017) and age (HR 1.06; 95% CI 1.03-1.08, p < 0.0001) were independent poor prognostic factor. Among N+ patients age (HR 1.04; 95% CI 1.00-1.07, p = 0.048), number of positive lymph nodes (HR 1.13; 95% CI 1.05-1.20, p = 0.0002) and PenA (HR 4.23; 95% CI 1.70-10.55, p = 0.002) were significantly correlated with poor prognosis at multivariate analysis.

CONCLUSIONS

Kodama PenA subtype was the most powerful independent prognostic factor in patients with nodal metastases. Its status should always be investigated in EGCs patients.

A non-randomized confirmatory trial of an expanded indication for endoscopic submucosal dissection for intestinal-type gastric cancer (cT1a): the Japan Clinical Oncology Group study (JCOG0607)

BACKGROUND

Endoscopic resection has been limited to intestinal-type gastric cancer (cT1a) with a low risk of lymph node metastasis (T1a ≤2 cm, without ulcers). This single-arm confirmatory trial evaluated the efficacy and safety of endoscopic submucosal dissection (ESD) for >2 cm ulcer-negative and ≤3 cm ulcer-positive intestinal-type gastric cancer (cT1a).

METHODS

The eligibility criteria included endoscopically diagnosed cT1a, a single primary intestinal-type gastric adenocarcinoma, an ulcer-negative lesion of any size or a ≤3 cm ulcer-positive lesion, cN0M0, and no prior treatment. If ESD resulted in noncurative resection, surgical resection was added. The primary endpoint was the 5-year overall survival (OS) (planned sample size was 470, with a one-sided alpha level of 2.5%). The threshold 5-year OS was 86.1%.

RESULTS

We enrolled 470 early gastric cancer patients [median tumor size, 25 (5-130) mm] from 29 institutions between June 2007 and October 2010. These patients had 152 ulcer-negative lesions (>2 and ≤3 cm), 111 ulcer-negative lesions (>3 cm), and 207 ulcer-positive lesions (≤3 cm). The success rate for en block resection was 99.1% (466/470). Additional gastrectomy was conducted in 131 patients (28%) who did not fulfill the curative resection criteria. The 5-year OS of all patients was 97.0% (95% confidence interval, 95.0-98.2%), which was higher than the threshold 5-year OS (86.1%). The 317 patients who satisfied the curative resection criteria had no recurrence. There were no ESD-related grade 4 adverse events.

CONCLUSION

ESD for early gastric cancers that met the expanded criteria for intestinal-type gastric cancer (cT1a) was acceptable and should be the standard treatment instead of gastrectomy.

Quantitative proteomic analysis of gastric cancer tissue reveals novel proteins in platelet-derived growth factor b signaling pathway

Gastric cancer is one of the most common cancers in Asian countries. Searching for reliable biomarkers involving the development of gastric cancer is important for clinical practice. Quantitative proteomics has become an important method contributed to the discovery of novel diagnostic or therapeutic targets for the management of cancer. Here, we identified differently expressed proteins in gastric cancer and normal gastric tissues by using the high resolution mass spectrometer. Among the total of 2280 identified proteins, 87 were differentially expressed between gastric cancer and normal gastric tissues. Notably, several significant proteins are in the PDGF-B signaling pathway, including peroxiredoxin5 (PRDX5), S100A6, calreticulin (CALR) and cathepsin D (CTSD), which were validated by western blot. Furthermore, upstream regulators including PDGF-B, PDGFR-β, Akt, eIF4E and p70s6K were found significantly increased in the gastric cancer tissues. In addition, silencing of PRDX5 and PDGF-B suppressed the proliferation of gastric cancer cells in vitro. The administration of exogenous PDGF-BB recovered the reduced expression of PDGF-B signaling pathway in PDGF-B knockdown cells. Taken together, our findings suggested that PDGF-B signaling pathway plays an important role in the regulation of gastric cancer proliferation and the inhibition of this pathway may be a potential approach for treatment of gastric cancer.

Long-Term Outcome of Endoscopic Resection vs. Surgery for Early Gastric Cancer: A Non-inferiority-Matched Cohort Study

OBJECTIVES

Few studies have compared the long-term outcomes of endoscopic resection and surgery. The aim of this study was to compare the long-term outcomes of endoscopic resection with those of surgery for early gastric cancer (EGC).

METHODS

We reviewed prospectively collected data of patients who had undergone endoscopic resection (1,290 patients) or surgery (1,273 patients) for EGC. To reduce the effect of selection bias, we performed a propensity score-matching analysis between the two groups. The primary outcome was overall survival (OS). The secondary outcomes were disease-specific survival, disease-free survival (DFS), recurrence-free survival (RFS), occurrence of metachronous gastric cancer, treatment-related complications, length of hospital stay, and 30-day outcomes. The study was designed as a non-inferiority study and tested in an intention-to-treat analysis.

RESULTS

In a propensity-matched analysis of 611 pairs, the 10-year OS proportion was 96.7% in the endoscopic resection group and 94.9% in the surgery group (P=0.120) (risk difference -1.8%, 95% confidence interval (CI) -4.04-0.44, Pnon-inferiority=0.014), which met the non-inferiority criterion. In contrast, the 10-year RFS proportion was 93.5% in the endoscopic resection group and 98.2% in the surgery group (P<0.001) (risk difference 4.7%, 95% CI 2.50-6.97, Pnon-inferiority=0.820), which did not meet the non-inferiority criterion, mainly because of metachronous recurrence in the endoscopic resection group. The rate of early complications was higher in the endoscopic resection group than in the surgery group (9.0 vs. 6.6%, P=0.024), whereas the rate of late complications was higher in the surgery group than in the endoscopic resection group (0.5 vs. 2.9%, P<0.001). In the multiple Cox regression analysis, patient's age, the comorbidity index, the performance index, sex, tumor morphology, and depth of invasion were predictors of OS in patients with EGC.

CONCLUSIONS

Endoscopic resection might not be inferior to surgery with respect to OS in patients with EGC lesions that meet the absolute or expanded criteria. However, DFS, RFS, and metachronous RFS might be lower after endoscopic resection than after surgery.

Long-term outcomes after D2 gastrectomy for early gastric cancer: survival analysis of a single-center experience in China

BACKGROUND

Early gastric cancer (EGC) is well accepted as having a favorable prognosis, but some patients experience an ominous outcome after curative resection. This study was aimed at evaluating predictive factors associated with prognosis of D2 gastrectomies in patients with early gastric cancer.

MATERIALS AND METHODS

A total of 518 patients with early gastric cancer who underwent D2 gastrectomies were reviewed in this study. The clinicopathological features and surgical outcomes were analyzed. The survival rate was estimated using the Kaplan-Meier method and compared by log rank test. Prognostic factors were analyzed using a multivariate Cox proportional hazards model.

RESULTS

The 5-year survival rate was 90.3%. Tumor infiltration, lymph node metastasis and lymphovascular invasion were significant prognostic factors for survival. Gender, age, tumor size, tumor location, macroscopic type and histological type were not significant prognostic factors. Multivariate analysis indicated that lymph node metastasis was an independent poor prognosis factor.

CONCLUSIONS

Early gastric cancers with lymph node metastasis have a relatively poor prognosis after standard surgery. Even after curative resection, patients with EGC with positive lymph nodes should be closely followed and be considered as candidates for comprehensive therapies.

Risk of lymph node metastases from early gastric cancer in relation to depth of invasion: experience in a single institution

BACKGROUND

An accurate assessment of potential lymph node metastasis is important for the appropriate treatment of early gastric cancers. Therefore, this study analyzed predictive factors associated with lymph node metastasis and identified differences between mucosal and submucosal gastric cancers.

MATERIALS AND METHODS

A total of 518 early gastric cancer patients who underwent radical gastrectomy were reviewed in this study. Clinicopathological features were analyzed to identify predictive factors for lymph node metastasis.

RESULTS

The rate of lymph node metastasis in early gastric cancer was 15.3% overall, 3.3% for mucosal cancer, and 23.5% for submucosal cancer. Using univariate analysis, risk factors for lymph node metastasis were identified as tumor location, tumor size, depth of tumor invasion, histological type and lymphovascular invasion. Multivariate analysis revealed that tumor size >2 cm, submucosal invasion, undifferentiated tumors and lymphovascular invasion were independent risk factors for lymph node metastasis. When the carcinomas were confined to the mucosal layer, tumor size showed a significant correlation with lymph node metastasis. On the other hand, histological type and lymphovascular invasion were associated with lymph node metastasis in submucosal carcinomas.

CONCLUSIONS

Tumor size >2 cm, submucosal tumor, undifferentiated tumor and lymphovascular invasion are predictive factors for lymph node metastasis in early gastric cancer. Risk factors are quite different depending on depth of tumor invasion. Endoscopic treatment might be possible in highly selective cases.

The Serum Immunoglobulin G Glycosylation Signature of Gastric Cancer

Biomarkers may facilitate detection of gastric cancer at an earlier stage and reduce mortality. Here we sought to determine if the glycosylation profile of serum immunoglobulin G (IgG) could distinguish patients with non-atrophic gastritis (NAG), duodenal ulcer (DU) and gastric cancer (GC). Serum IgG was released and analyzed using nano-LC-TOF mass spectrometry. Statistically significant false discovery rate (FDR)-adjusted p-values were observed for 18 glycans, eight that differed significantly between NAG and GC, three that distinguished NAG from DU, and eight that differed between DU and GC. The IgG glycosylation signature may be useful as a predictive marker for gastric cancer.

Future perspective of gastric cancer endotherapy

Endoscopic resection of early gastric cancer (EGC) has proven safety and efficacy, and is the established standard of care in Japan. In the past decade, it is increasingly established worldwide. The endoscopic submucosal dissection (ESD) is superior to endoscopic mucosal resection (EMR) technique as it is designed to provide adequate staging and long-term curative therapy-based on the en bloc R0 specimen irrespective of the size and/or location of the tumor coupled with the reliable pathological specimen. However, ESD is still requiring skilled and experienced endoscopist to perform because of complex procedures, higher complication and causing long-time consuming. The learning and application of these relatively complex endoscopic techniques for EGC has been shown across the world. Thus, a standardized ESD training system is urgently needed to disseminate safe and effective ESD technique to practices with limited ESD experience. In recent years, several innovations providing solutions to easier and safer performance of ESD have emerged. Those increase control of surgical effectors manipulating the target tissue, and enhance performance in complex surgical tasks. Very recently, the use of the laparoscopic and endoscopic cooperative surgery (LECS) procedure is indicated for EGC that would be difficult to treat with ESD. As an ultimate gastric cancer endotherapy with a reasonable surgical time, LECS might be promising method at this stage. The indications for LECS for EGC could be expanded in the future, which could result in increasingly successful gastric cancer treatment.

[Search for potential gastric cancer biomarkers using low molecular weight blood plasma proteome profiling by mass spectrometry]

Gastric cancer, one of the most widespread malignant tumors, still lacks reliable serum/plasma biomarkers of its early detection. In this study we have developed, unified, and tested a new methodology for search of gastric cancer biomarkers based on profiling of low molecular weight proteome (LMWP) (1-17 kDa). This approach included three main components: sample pre-fractionation, matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS), data analysis by a bioinformatics software package. Applicability and perspectives of the developed approach for detection of potential gastric cancer markers during LMWP analysis have been demonstrated using 69 plasma samples from patients with gastric cancer (stages I-IV) and 238 control samples. The study revealed peptides/polypeptides, which may be potentially used for detection of this pathology.

Gastric ESD: current status and future directions of devices and training

Endoscopic mucosal resection (EMR) of early gastric cancer, which has been proved to be safe and effective and is the established standard of care in Japan, has become increasingly established worldwide in the past decade. Endoscopic submucosal dissection (ESD) is superior to EMR, as it is designed to provide precise pathologic staging and long-term curative therapy based on an en bloc R0 specimen irrespective of the size and/or location of the tumor. However, ESD requires highly skilled and experienced endoscopists. The introduction of ESD to the Western world necessitates collaborations between Eastern and Western endoscopists, pathologists, and surgeons.

Converting a microarray signature into a diagnostic test: a trial of custom 74 gene array for clarification and prediction the prognosis of gastric cancer

Background

Gastric cancer (GC) is associated with high mortality rates and an unfavorable prognosis at advanced stages. In addition, there are no effective methods for diagnosing gastric cancer at an early stage or for predicting the outcome for the purpose of selecting patient-specific treatment options. Therefore, it is important to investigate new methods for GC diagnosis.

Methodology/Principal Findings

To facilitate its use in a diagnostic setting, a group of 74 genes with diagnostic and prognostic information was translated into a customized microarray containing a reduced set of 1,042 probes suitable for high throughput processing. In this report, we demonstrate for the first time that the custom mini-array can be used as a reliable diagnostic tool in gastric cancer. With an AUC value of 0.565 (95% CI 0.305-0.825) indicating a perfect test, the sensitivity and specificity of diagnosis from the ROC curve were calculated to be 70% and 80%, respectively.

Conclusions/Significance

The data clearly demonstrate the reproducibility and robustness of the small custom-made microarray. The array is an excellent tool for classifying and predicting the outcome of disease in gastric cancer patients.

A case of early gastric cancer with solitary metastasis to the pleura

The incidence of early gastric cancer (EGC) has increased to >50% in Korea owing to a higher detection rate caused by rapid advances in diagnostic instrumentation. EGC with distant metastasis has been rarely reported. Here, we report the case of a 76-year-old woman in whom general EGC was initially diagnosed by endoscopy and endoscopic ultrasonography. She subsequently underwent endoscopic submucosal dissection (ESD). Histological examination of the ESD specimen revealed that neoplastic cells were located predominantly in the submucosal layer and submucosal lymphatic channels. Metastatic cancer cells were also found in the pleural effusion. After conducting all analyses, including immunohistochemical staining, we concluded that the patient had primary EGC with pleural metastasis.

Biomarkers of Helicobacter pylori-associated gastric cancer

Helicobacter pylori-associated gastric cancer is a major cause of morbidity and mortality worldwide, and is predicted to become even more common in developing countries as the population ages. Since gastric cancer develops slowly over years to decades, and typically progresses though a series of well-defined histologic stages, cancer biomarkers have potential to identify asymptomatic individuals in whom surgery might be curative, or even those for whom antibiotics to eradicate H. pylori could prevent neoplastic transformation. Here we describe some of the challenges of biomarker discovery, summarize current approaches to biomarkers of gastric cancer, and explore some recent novel strategies.

Early gastric cancer: diagnosis, staging, and clinical impact. Evaluation of 530 patients. New elements for an updated definition and classification

BACKGROUND

The prevention and early diagnosis of gastric cancer permit clinicians to discover the tumor in the initial phase, during which time it can be completely eradicated, endoscopically or surgically. Since Murakami gave the definition of early gastric cancer (EGC) in 1971, many authors have identified various subtypes of EGC with different morphological characteristics and clinical behaviour.

METHODS

We evaluated retrospectively 530 patients: the median follow-up time was 10.4 months (range 0.3-29.2). All tumors were classified according to the macroscopic and microscopic criteria proposed by the Japanese Society of Gastroenterology and Endoscopy and Lauren, respectively. The infiltrative growth pattern was evaluated according to Kodama's classification. Only tumor-related death was considered as an endpoint of interest for the survival analysis.

RESULTS

The overall survival rates of our patients were 94 % (95 % CI, 92-96) and 90 % (95 % CI, 87-93) at 5 and 10 years, respectively. Only 44 patients (8.3 %) died of the disease. Kodama's type (p < 0.0001), lymph node status, both for number and pathological stage according to the 7th Edition of TNM (p < 0.0001), and depth of infiltration (p = 0.0006) were significant prognostic factors in univariate analysis. The multivariate analysis identified Kodama's PENA type (HR, 3.91; 95 % CI, 2.08-7.33; p < 0.0001) and lymph node status for more than three positive nodes versus negative nodes (HR, 12.78; 95 % CI, 5.37-30.43; p < 0.0001) as the only independent prognostic factors in our series.

CONCLUSION

Lymph node status, especially when more than three lymph nodes are involved, is the most important prognostic factor in EGC. However, it is also important to evaluate the infiltrative growth pattern of the cancers in their early phase according to Kodama's classification, considering PEN A type lesions to be more aggressive than the other EGC types. Then, we propose new elements for an updated definition and classification of EGC, with an important clinical impact on the treatment of patients.

Endoscopic resection (endoscopic mucosal resection/ endoscopic submucosal dissection) for early gastric cancer

Endoscopic resection of early gastric cancer is a well-established standard therapy in Japan and Korea, and is increasingly used in other countries. Endoscopic resection should be curative for patients, and safe, easy and effective not only for patients, but also for endoscopists. Endoscopic submucosal dissection (ESD) is superior to standard endoscopic mucosal resection (EMR) as it is designed to provide en bloc R0 resection regardless of size and/or location. Correct pathological assessment of en bloc resected specimens is crucial for accurate diagnosis and patient stratification for the risk of metastasis. Outcome studies in Japan and Korea, countries with the highest incidence of gastric cancer, have shown that ESD is efficacious in leading to a good long-term outcome; however, ESD requires an experienced endoscopist with a high skill level. Expanded indications for endoscopic resection have been proposed, especially after large en bloc resection have been accomplished using ESD. The use of ESD could be of huge benefit for the management of gastrointestinal superficial neoplasms. However, for ESD to become a viable therapeutic option, it requires close and supportive working relationships between endoscopists, pathologists and surgeons.

Depressed type of intramucosal differentiated-type gastric cancer has high cell proliferation and reduced apoptosis compared with the elevated type

BACKGROUND

The depressed type of early gastric cancer, in comparison to the elevated type, tends to invade the submucosal layer and metastasize to the lymph nodes. This study compared the differences in tumor cell proliferation and apoptosis between the elevated and depressed types of intramucosal differentiated gastric cancer.

METHODS

A total of 57 intramucosal differentiated gastric cancers were studied. Twenty samples were the elevated type and 37 were the depressed type. The tumor cells were analyzed by immunohistochemistry for Ki-67, Bcl-2, and Bax, and terminal deoxynucleotidyl transferase 2´-deoxyuridine, 5´-triphosphate (dUTP)-biotin nick end labeling was carried out to detect apoptotic cells.

RESULTS

(1) The Ki-67 labeling index (KI) was higher in the depressed type (median: 38.6) than in the elevated type (median: 21.2). (2) Immunopositivity for Bax and the apoptosis index (AI) were lower in the depressed type (median AI: 0.20) than the elevated type (median AI: 1.05). (3) The AI/KI was lower in the depressed type (median: 0.17) than in the elevated type (median: 5.57). (4) The AI in the tumors with a Bcl-2-negative and Bax-positive pattern (median: 2.0) was higher than that in the tumors with a Bcl-2-positive and Bax-negative pattern (median: 0.2).

CONCLUSION

These results show that, regarding cell proliferation and apoptosis, the depressed type of intramucosal differentiated-type gastric cancer has high malignant potential in comparison to the elevated type.

Discovery of biomarkers for gastric cancer: a proteomics approach

Gastric cancer is the second leading cause of cancer-related deaths worldwide. Although many treatment options exist for patients with gastric tumors, the incidence and mortality rate of gastric cancer are on the rise. The early stages of gastric cancer are non-symptomatic, and the treatment response is unpredictable. This situation is further aggravated by a lack of diagnostic biomarkers that can aid in the early detection and prognosis of gastric cancer and in the prediction of chemoresistance. Moreover, clinical surgical specimens are rarely obtained, and traditional biomarkers of gastric cancer are not very effective. Many studies in the field of proteomics have contributed to the discovery and establishment of powerful diagnostic tools (e.g., ProteinChip array) in the management of cancer. The evolution in proteomic technologies has not only enabled the screening of a large number of samples but also enabled the identification of pathologically significant proteins, such as phosphoproteins, and the quantitation of difference in protein expression under different conditions. Multiplexed assays are used widely to accurately fractionate various complex samples such as blood, tissue, cells, and Helicobacter pylori-infected specimens to identify differentially expressed proteins. Biomarker detection studies have substantially contributed to the areas of secretome, metabolome, and phosphoproteome. Here, we review the development of potential biomarkers in the natural history of gastric cancer, with specific emphasis on the characteristics of target protein convergence.

Influential factors in procedure time of endoscopic submucosal dissection for gastric cancer with fibrotic change

BACKGROUND

Factors correlating with the technical difficulty of endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) are still unclear. EGC coexisting with fibrosis inside lesions has been a common therapeutic indication for ESD. The aim of this study was to clarify the most important factor related to difficult ESD for EGC.

PATIENTS AND METHODS

Fifty-six patients (49 male and seven female, median age 66 years) who received ESD at a single institute for EGC with fibrosis in the resected lesion were selected. Various clinicopathological factors, including the histological findings of fibrotic changes within the cancer area in the resected specimen, were evaluated statistically for correlation with ESD procedure time.

RESULTS

  Univariate linear regression analysis with logarithmic ESD procedure time revealed the upper-third portion of lesion in the stomach (P = 0.02), histological classification of dense fibrosis (ulcer/ulcer scar-III/IV) within EGC (P < 0.001), and presence of peptic ulcer other than EGC (P = 0.04). Areas of the resected specimen (P < 0.001) and fibrosis (P < 0.001) were significant factors related to prolonged operation times. Multivariate analysis demonstrated that the upper-third portion of lesion (P = 0.007), ulcer/ulcer scar-III/IV findings (P = 0.006), and area of resected specimen (P = 0.006) were significant independent factors influencing ESD procedure time.

CONCLUSION

Histological findings of fibrotic changes coexisting with EGC are closely related to technical difficulty in ESD as well as the location of tumors. Preoperative precise evaluation of fibrotic changes within EGC may be helpful to predict a technical difficulty in ESD.

Histopathological phenotypes of early gastric cancer and its background mucosa

Recent advances in endoscopic submucosal dissection (ESD) techniques contribute to endoscopic treatment of early gastric cancer (EGC). Recognition of chronic atrophic gastritis as the background is important for high-quality detection and diagnosis of EGC. But, relationships between EGC and atrophy of the background gastric mucosa caused by Helicobacter pylori are not well understood. The present study demonstrated histopathological phenotypes of EGC, as well as chronic atrophic gastritis as background mucosa of EGC. We evaluated mucosal heights, number of glands, and degree of intestinal metaplasia (IM) of the background gastric mucosa, using 81 cases of EGC resected by ESD. Gastric phenotype cancer cases showed IM of the background gastric mucosa less frequently, compared with intestinal phenotype cancer cases (score of IM, 1.15 vs. 1.65, P = 0.012). The average mucosal heights around EGC were lower in moderately to poorly differentiated adenocarcinoma cases than well differentiated adenocarcinoma cases (442.6 µm vs. 500.2 µm, P = 0.011). The mucosal atrophy indicated by average heights of background mucosa was low in the gastric phenotype cancer cases, compared with the intestinal phenotype cancercases (452.8 µm vs. 505.6 µm, P = 0.018). In the fundic gland area, the mucosal heights were low in the gastric phenotype cancer cases, compared with the intestinal phenotype cancer cases (413.2 µm vs. 495.5 µm, P = 0.015). Our results using EGC specimens indicated that gastric phenotype cancer and moderately to poorly differentiated adenocarcinoma had atrophic background mucosa with lower mucosal heights and less IM. The atrophic gastric mucosa with less IM is thought to play an important role in gastric carcinogenesis, especially tumoriogenesis of gastricphenotype cancer.

Targeting miR-375 in gastric cancer

INTRODUCTION

Gastric cancer remains a major cancer burden in the world, with a poor 5-year survival rate. It is necessary to develop new effective therapeutic strategies to improve the long-term clinical outcome. MicroRNA (miRNA), a class of small non-coding RNA, has been identified as a key regulator of gene expression, and is implicated in the pathogenesis of gastric cancer.

AREAS COVERED

This review summarizes the role of miRNAs in gastric carcinogenesis, with an emphasis on the expression and function of miR-375 in gastric cancer and beyond. It also discusses the opportunities and challenges of miR-375 as a potential therapeutic target for gastric cancer. The genes targeted by miR-375, including JAK2 and 3'-phosphoinositide dependent protein kinase-1 (PDK1), are also candidates for gastric cancer therapy.

EXPERT OPINION

Although radical surgery and rational chemotherapy are still the main treatment for gastric cancer, targeting miRNAs, in combination with other conventional therapies, may serve as a promising therapy strategy to improve the clinical outcome.

Lymph node metastasis of gastric cancer

Despite a decrease in incidence in recent decades, gastric cancer is still one of the most common causes of cancer death worldwide [1]. In areas without screening for gastric cancer, it is diagnosed late and has a high frequency of nodal involvement [1]. Even in early gastric cancer (EGC), the incidence of lymph node (LN) metastasis exceeds 10%; it was reported to be 14.1% overall and was 4.8 to 23.6% depending on cancer depth [2]. It is important to evaluate LN status preoperatively for proper treatment strategy; however, sufficient results are not being obtained using various modalities. Surgery is the only effective intervention for cure or long-term survival. It is possible to cure local disease without distant metastasis by gastrectomy and LN dissection. However, there is no survival benefit from surgery for systemic disease with distant metastasis such as para-aortic lymph node metastasis [3]. Therefore, whether the disease is local or systemic is an important prognostic indicator for gastric cancer, and the debate continues over the importance of extended lymphadenectomy for gastric cancer. The concept of micro-metastasis has been described as a prognostic factor [4-9], and the biological mechanisms of LN metastasis are currently under study [10-12]. In this article, we review the status of LN metastasis including its molecular mechanisms and evaluate LN dissection for the treatment of gastric cancer.

A potential role of collagens expression in distinguishing between premalignant and malignant lesions in stomach

Lack of clinical biomarkers for early gastric cancer without specific early symptoms leads to delayed diagnosis, which contributes to high mortality of gastric cancer. Here, we used oligonucleotide microarray to systematically examine differential gene expression among 33 samples from normal, premalignant, and malignant lesions in stomach. A focal adhesion pathway mainly composed of collagen genes was found to have a significantly different expression profile in gastric cancers compared to premalignant lesions. A subset of collagen genes efficiently separated malignant from premalignant tissues, and two representative genes COL11A1 and COL1A1 were validated in 42 tissue samples with quantitative reverse transcription-PCR and in situ hybridization. The data above suggest that focal adhesion pathway may have a role in the pathogenesis of gastric cancer, and the expression profile of collagen genes may be a potential biomarker to distinguish malignant from premalignant lesions in stomach.

Predictive factors for local recurrence and incomplete resection of early gastric cancer treated by endoscopic resection: a Western experience

BACKGROUND

Early gastric cancer (EGC) is defined as adenocarcinoma limited to the mucosa or submucosa regardless of lymph node involvement. Local EGC recurrence rates have been described in up to 6% of cases.

OBJECTIVES

To evaluate predictive factors for incomplete resection and local recurrence of EGC treated by endoscopic mucosal resection (EMR) that was followed up for at least one year.

METHODS

From June 1994 to December 2005, 46 patients with EGC underwent EMR. Possible predictive factors for incomplete endoscopic resection and local recurrence were identified by medical chart analysis. Demographic, endoscopic and histopathological data were retrospectively evaluated. EMR was considered complete or incomplete. Patients from the complete resection group were divided into subgroups (with and without local EGC recurrence).

RESULTS

Complete resection was possible in 36 cases (76.6%). Predictive factors for incomplete resection were tumour location (P=0.035), histological type (P=0.021), lesion size (P=0.022) and number of resected fragments (P=0.013). On multivariate analysis, undifferentiated histological type (OR 0.8; 95% CI 0.036 to 0.897) and number of resected fragments (OR 7.34; 95% CI 1.266 to 42.629) were independent predictive factors for incomplete resection. In the complete resection group, a larger lesion size was associated with a higher the number of resected fragments (P=0.018). Local recurrence occurred in nine cases (25%). Use of the cap technique was the only predictive factor for local recurrence in five of seven cases (71.4%) (P=0.006).

CONCLUSIONS

A larger lesion size was associated with a higher number of resected fragments. Undifferentiated adenocarcinoma and piecemeal resection were predictive factors for incomplete resection. Technique type was a predictive factor for local EGC recurrence.

Tripartite motif-containing 29 (TRIM29) is a novel marker for lymph node metastasis in gastric cancer

BACKGROUND

Tripartite motif-containing 29 (TRIM29) belongs to the TRIM protein family, which has unique structural characteristics, including multiple zinc finger motifs and a leucine zipper motif. TRIM29, also known as ataxia telangiectasia group D complementing gene, possesses radiosensitivity suppressor functions. Although TRIM29 has been reported to be underexpressed in prostate and breast cancer, its expression in gastrointestinal cancer has not been studied.

METHODS

By use of real-time reverse transcriptase-polymerase chain reaction, we analyzed TRIM29 mRNA expression status with respect to various clinicopathological parameters in 124 patients with gastric cancer. An immunohistochemical study was also conducted.

RESULTS

The expression of TRIM29 was far higher in gastric cancer tumor tissue. Increased TRIM29 mRNA expression was markedly associated with such parameters as histological grade, large tumor size, extent of tumor invasion, and lymph node metastasis. In the TRIM29 high-expression group, it was an independent predictor for lymph node metastasis. Furthermore, patients with high TRIM29 mRNA expression showed a far poorer survival rate than those with low TRIM29 mRNA expression.

CONCLUSIONS

TRIM29 expression may serve as a good marker of lymph node metastasis in gastric cancer.

Endoscopic resection of early gastric cancer

The purpose of this review is to examine recent advances in the techniques and technologies of endoscopic resection of early gastric cancer (EGC). Endoscopic mucosal resection (EMR) of EGC, with negligible risk of lymph node metastasis, is a standard technique in Japan and is increasingly becoming accepted and regularly used in Western countries. EMR is a minimally invasive technique which is safe, convenient, and efficacious; however, it is insufficient when treating larger lesions. The evidence suggests that difficulties with the correct assessment of depth of tumor invasion lead to an increase in local recurrence with standard EMR when lesions are larger than 15 mm. A major factor contributing to this increase in local recurrence relates to lesions being excised piecemeal due to the technical limitations of standard EMR. A new development in endoscopic techniques is to dissect directly along the submucosal layer -- a procedure called endoscopic submucosal dissection (ESD). This allows the en-bloc resection of larger lesions. ESD is not necessarily limited by lesion size and it is predicted to replace conventional surgery in dealing with certain stages of ECG. However, it still has a higher complication rate when compared to standard EMR, and it requires high levels of endoscopic skill and experience. Endoscopic techniques, indications, pathological assessment, and methods of endoscopic resection of EGC need to be established for carrying out appropriate treatment and for the collation of long-term outcome data.

Endoscopic resection of early gastric cancer

The purpose of this review is to examine recent advances in the techniques and technologies of endoscopic resection of early gastric cancer (EGC). Endoscopic mucosal resection (EMR) of EGC, with negligible risk of lymph node metastasis, is a standard technique in Japan and is increasingly becoming accepted and regularly used in Western countries. EMR is a minimally invasive technique which is safe, convenient, and efficacious; however, it is insufficient when treating larger lesions. The evidence suggests that difficulties with the correct assessment of depth of tumor invasion lead to an increase in local recurrence with standard EMR when lesions are larger than 15 mm. A major factor contributing to this increase in local recurrence relates to lesions being excised piecemeal due to the technical limitations of standard EMR. A new development in endoscopic techniques is to dissect directly along the submucosal layer -- a procedure called endoscopic submucosal dissection (ESD). This allows the en-bloc resection of larger lesions. ESD is not necessarily limited by lesion size and it is predicted to replace conventional surgery in dealing with certain stages of ECG. However, it still has a higher complication rate when compared to standard EMR, and it requires high levels of endoscopic skill and experience. Endoscopic techniques, indications, pathological assessment, and methods of endoscopic resection of EGC need to be established for carrying out appropriate treatment and for the collation of long-term outcome data.

Endoscopic submucosal dissection of early gastric cancer

The purpose of this review was to examine a remarkable technical advance regarding the indications for and the technique of endoscopic resection of early gastric cancer. Endoscopic mucosal resection (EMR) of early gastric cancer with no risk of lymph node metastasis has been a standard technique in Japan, probably owing to the high incidence of gastric cancer in Japan and the fact that more than half of Japanese gastric cancer cases are diagnosed at an early stage. Very recently, several EMR techniques have become increasingly accepted and regularly used in Western countries. Although these minimally invasive techniques are safe, convenient, and efficacious, they are unsuitable for large lesions in particular. Difficulty in correctly assessing the depth of tumor invasion and an increase in local recurrence when standard EMR procedures are used have been reported in cases of large lesions, because such lesions are often resected piecemeal owing to the technical limitations of standard EMR. A new development in therapeutic endoscopy, called endoscopic submucosal dissection (ESD), allows the direct dissection of the submucosa, and large lesions can be resected en bloc. ESD is not limited by resection size and is expected to replace surgical resection. However, it is still associated with a higher incidence of complications than standard EMR procedures and requires a high level of endoscopic skill. The endoscopic indications, techniques, and management of complications of ESD for early gastric cancer for properly carrying out established therapeutic endoscopy are described.

Clinical outcome of high segmental gastrectomy for early gastric cancer in the upper third of the stomach

BACKGROUND

Reflux oesophagitis is commonly encountered in the surgical treatment of cancer of the upper third of the stomach. The aim of this study was to describe a novel surgical technique and evaluate the clinical outcome of high segmental gastrectomy for early-stage proximal gastric cancer.

METHODS

Thirty consecutive patients with early gastric cancer located in the upper third of the stomach were included, of whom 12 underwent high segmental gastrectomy and 18 underwent proximal gastrectomy with jejunal interposition. The incidence of reflux oesophagitis and nutritional parameters were compared between the two groups at 1 year after operation.

RESULTS

One patient had mild reflux symptoms and two had endoscopic evidence of oesophagitis 1 year after high segmental gastrectomy. Half of the patients who had proximal gastrectomy had reflux symptoms of varying severity and 14 had endoscopic evidence of oesophageal changes at 1 year after surgery. There were significant differences between groups in the incidence of reflux symptoms (P = 0.016) and endoscopically detected gastro-oesophagitis (P < 0.001). There were no adverse events in either group, and the survival rate after high segmental gastrectomy appeared favourable.

CONCLUSION

Selected patients with early-stage proximal gastric cancer benefit from high segmental gastrectomy in terms of reduced reflex oesophagitis, without jeopardizing curability.

Endoscopic resection of early gastric cancer: the Japanese perspective

PURPOSE OF REVIEW

To examine recent advances in the techniques and technologies of endoscopic resection of early gastric cancer.

RECENT FINDINGS

Endoscopic mucosal resection of early gastric cancer with no risk of lymph node metastasis has been a standard technique in Japan and is increasingly becoming accepted and regularly used in Western countries. Though this minimally invasive technique is a safe, convenient and efficacious method, it is insufficient for larger lesions. Difficulties in correctly assessing the depth of tumour invasion and increases in local recurrence by standard endoscopic mucosal resection have been reported in lesions larger than 15 mm. This is because such lesions are often resected piecemeal due to the technical limitation of standard endoscopic mucosal resection. New developments in endoscopic resection techniques to dissect the submucosa directly, called endoscopic submucosal dissection, allows resections of larger lesions en bloc. There are no limitations in resection size in endoscopic submucosal dissection, which is expected to replace surgery. This technique, however, still has higher complications rates than standard endoscopic mucosal resection and requires highly skilled endoscopists.

SUMMARY

The techniques, indications, and pathological assessment methods of endoscopic resection of early gastric cancer are described so that proper treatment guidelines can be established and long-term outcome data can be assessed.

Clinical outcomes of EMR for gastric tumors: historical pilot evaluation between endoscopic submucosal dissection and conventional mucosal resection

BACKGROUND

EMR is currently a standard treatment for mucosal gastric tumors. Endoscopic submucosal dissection (ESD) has been developed for en bloc resection.

OBJECTIVE

We evaluated the clinical outcomes of ESD compared with conventional EMR.

DESIGN

Not applicable.

SETTING

A historical control study was performed between EMR and ESD.

PATIENTS

EMR of 245 gastric tumors was performed in 229 patients. Lesions were divided into two groups. Conventional EMR was performed in group A from February 1999 to June 2001, and ESD was performed in group B from July 2001 to March 2004. Group B was divided into subgroups: subgroup B-1 underwent ESD from July 2001 to March 2003 and subgroup B-2 from April 2003 to March 2004.

INTERVENTIONS

All lesions were resected with conventional EMR or with ESD.

MAIN OUTCOME MEASUREMENTS

En bloc resection rate, rate in completeness of resection, required time, remnant ratio, and complications were evaluated.

RESULTS

With regard to lesions >10 mm in size, the en bloc resection rate and the rate in completeness of resection of group B was significantly higher than that of group A (p < 0.01). Although the required time was longer in group B than A (p < 0.01), it was shorter in subgroup B-2 compared with B-1 (p < 0.05) with lesions < or =10 mm in size. The remnant ratio and perforation rate were not different between groups.

LIMITATIONS

Not applicable.

CONCLUSIONS

The en bloc resection rate was better with ESD than with conventional EMR. The required time was longer in ESD, but this disadvantage might be improved with experience.

Original communications recurrence in early gastric cancer

In a retrospective study of 503 cases of early gastric cancer, 17 of the patients had died of a recurrence of the gastric cancer and 72 had died of unrelated causes. The cumulative recurrence mortality rates were 2.2% at 9 years for mucosal cancer and 8.4% at 8 years for submucosal cancer. The recurrence patterns of early gastric cancer were hematogenic metastasis to the liver, lung, or bone (nine cases), recurrence from lymph nodes (three cases), and recurrence in the residual stomach (five cases). Submucosal cancers with a macroscopically elevated appearance, lymph node metastasis, and evidence of vessel invasion were the high-risk cancers for hematogenic recurrence, and adjuvant chemotherapy should be prescribed. Two cases of lymph node recurrence were attributed to inadequacy of lymph node dissection. Because metastasis to the group 2 lymph nodes was noted in 1.5% of cases of early gastric cancer and a macroscopic diagnosis of nodal status was inaccurate, complete dissection should be performed regardless of identification of metastasis. Five cases of recurrence in the residual stomach were attributed to overlooked lesions of multiple carcinoma and were detected at an advanced stage. Careful and regular postoperative follow-up is required to detect these recurrences at an early stage. (SURGERY 1990;107:489–95).

Distribution of the deepest penetrating point of minute submucosal gastric cancer

BACKGROUND

Accurate assessment of depth of invasion is critical in decision-making for additional surgery after endoscopic resection of early gastric cancer (EGC). Although this depth of invasion is determined at the deepest point of submucosal invasion (DPSI), there is no literature describing the distribution of deepest invasion point.

OBJECTIVE

To describe the location of the DPSI, and to determine whether it is possible to predict this point by clinicopathological features before treatment.

METHODS

One hundred and ninety-five lesions of EGC with minute submucosal invasion, which had been resected en bloc between 1991 and 2003, were reviewed. For each lesion, we recorded the location of the DPSI as being in one of three areas demarcated by three concentric equal distance rings. We also examined the correlation between the location of the deepest penetration and the clinicopathological characteristics.

RESULTS

The DPSI was located most often (53%) in the central, less often (31%) in the middle and least often (16%) in the outermost area. There was no significant correlation between the distribution of the deepest point and any clinicopathological features.

CONCLUSIONS

The DPSI was not always in the central area, and it was impossible to predict its location by clinicopathological features alone. To obtain an accurate measure of depth of tumor invasion, we must histologically assess the entire lesion by thin sections.

Characteristics of submucosal gastric carcinoma with lymph node metastatic disease

AIM

To study the correlation between lymph node metastatic disease and various pathological parameters. Lymph node metastasis is the most important factor in determining the prognosis of patients with early gastric cancer and is significantly associated with the submucosal invasion of neoplastic cells. However, the depth of submucosal layer as well as the depth of submucosal tumour invasion varies among different cases.

METHODS AND RESULTS

We studied various pathological parameters including the macroscopic appearance, location, size, area, differentiation, invasion depth, vascularity and fibrosis of submucosal gastric carcinomas (SMGC), using 248 age- and sex-matched tissue samples. The presence of lymphatic emboli, a larger area, greater size, a non-flat gross type and an increased vascularity of the tumour were significantly associated with node-positive SMGC. Among the three depth-related parameters, the ocular scale measurement, the sm3 method and the sm2 method, only the ocular scale measurement showed a significant correlation with node-positive SMGC. Using multivariate analysis, the incidence of lymph node metastasis increased in the lymphatic tumour emboli and in the tumours that invaded more than half of the submucosal layer.

CONCLUSIONS

These histological indicators seem to be a feasible and easy way to predict lymph node metastatic disease from limited surgery specimens. Pathologists should carefully investigate the lymphatic invasion of tumour cells and measure the invasion depth of the tumour.

Gastric MALT lymphomas are divided into three groups based on responsiveness to Helicobacter Pylori eradication and detection of API2-MALT1 fusion

Gastric MALT lymphoma shows unique features including regression by Helicobacter pylori eradication and API2-MALT1 fusion. We performed a molecular and clinicopathologic study for 115 cases. All eradication-responsive cases were devoid of API2-MALT1 fusion. All tumors positive for the fusion and all negative for H. pylori infection were nonresponsive to the eradication. Consequently, gastric MALT lymphomas were divided into three groups: Eradication-responsive and fusion-negative (group A, n = 72), eradication-nonresponsive and fusion-negative (group B, n = 22), and eradication-nonresponsive and fusion-positive (group C, n = 21). Group A tumors were characterized by low clinical stage and superficial gastric wall involvement, and group C tumors by low H. pylori infection rate, advanced clinical stage, and nuclear BCL10 expression. All group C tumors showed exclusively low-grade histology. Group B tumors, which have not been well recognized, frequently showed nodal involvement, deep gastric wall involvement, and advanced clinical stage, and sometimes an increased large cell component. A multivariate discriminant analysis revealed that responsiveness to the eradication could be predicted accurately by negative API2-MALT1 fusion, positive H. pylori infection, low clinical stage, and superficial gastric wall invasion, the former being the most important factor for the prediction. This 3-group categorization may be helpful for a comprehensive understanding of gastric MALT lymphoma.

Characteristics of gastric carcinoma invading the muscularis propria

BACKGROUND

Although gastric carcinomas invading the muscularis propria (mp) are classified among advanced-stage cancers in Japan, postoperative survival has been reported to approximate that in early gastric carcinoma. Characteristics of gastric carcinomas invading the mp, therefore, were compared to carcinomas invading only the mucosa (m) or submucosa (sm), and to those invading the subserosa (ss) or serosa (se).

METHODS

We retrospectively compared clinicopathologic findings, prognosis, and cause of death in patients with gastric carcinoma invading mp to those showing the other levels of invasion.

RESULTS

Patients with carcinomas invading the mp had larger tumors and more frequent lymph node and hematogenous metastases than those with carcinomas invading only m or sm. Yet they had smaller tumors and less frequent lymph node or peritoneal metastasis than those with carcinomas invading ss or se. Postoperative survival with tumors invading the mp was intermediate between that with carcinoma invading only m or sm and that with subserosal or serosal invasion. Causes of death with tumors invading muscularis were similar to those with carcinomas invading only m or sm.

CONCLUSIONS

Characteristics of gastric carcinoma invading the mp are intermediate between those of early and advanced carcinoma.

Characteristics of intramucosal gastric carcinoma with lymph node metastatic disease

AIM

Recent trends in treatment strategy for early gastric cancer (EGC) are towards minimal surgical procedures, such as endoscopic mucosal resection and laparoscopic partial resection. There is a possibility of incomplete removal of regional lymph nodes in minimal procedures, which may subsequently decrease the chance of a cure. Therefore, it is essential to be able to predict lymph node status and to make careful selection of candidates for mucosal resection.

METHODS AND RESULTS

We studied the relationship between lymph node status and various pathological parameters including macroscopic appearance, location, size, differentiation, presence of ulceration, vascularity, presence of gastritis cystica profunda-like glandular proliferation, disruption of the muscularis mucosae and invasion into the muscularis mucosae, using age- and sex-matched samples of 40 node-positive and 80 node-negative tumours to define the characteristics of intramucosal EGCs. Histological differentiation (P < 0.001), increased submucosal vascularity (P < 0.05), breakdown of the muscularis mucosae (P < 0.05), and invasion of tumour cells into the muscularis mucosae (P < 0.05) were correlated with the lymph node status of intramucosal gastric carcinoma. Furthermore, diffuse type histology (P < 0.001) and deep invasion into the muscularis mucosae (P < 0.05) were indicators of node-positive intramucosal EGCs.

CONCLUSIONS

These histological indicators are easily accessible and seem to predict lymph node metastatic disease in limited surgical specimens. Patients should be carefully selected despite the recent trend toward less invasive resection of EGCs, especially for those apparently confined to the mucosa.

Predictive factors for lymph node metastasis of differentiated submucosally invasive gastric cancer

BACKGROUND

For early gastric cancer, submucosal invasion may be unrecognized until histopathologic examination of the specimen obtained by EMR. Gastrectomy with lymphadenectomy is the standard treatment for such submucosal cancers. However, approximately 80% of submucosal cancers do not have lymph node metastasis. Unnecessary surgery could be avoided if a subgroup of patients with submucosal cancer with negligible risk of lymph node metastasis can be defined. This study was conducted to define such a subgroup.

METHODS

Data from 104 patients surgically treated for differentiated submucosal cancers were retrospectively collected. A multivariate analysis of clinicopathologic factors was performed to identify predictive factors for lymph node metastasis.

RESULTS

Three independent risk factors, namely, female gender (p=0.0174), deep invasion (> or =500 microm) into the submucosal layer (p=0.001), and presence of lymphatic involvement (p < 0.0001) were associated with lymph node metastasis. Lymph node metastasis was not observed in any patient who had limited submucosal invasion and absence of lymphatic involvement. The rate of lymph node metastasis was calculated to be 80% in patients who had both deep submucosal invasion and lymphatic involvement.

CONCLUSIONS

If endoscopic resection specimens exhibit no deep penetration (<500 microm) into the submucosal layer and lymphatic involvement is absent, EMR may be sufficient treatment for submucosal well-differentiated early gastric cancers. A long-term follow-up study of patients with such lesions treated by EMR alone is required.

MR imaging of gastric cancer in vitro: accuracy of invasion depth diagnosis

The purpose of this study was to evaluate the accuracy of grading cancerous invasion of the gastric wall in vitro using magnetic resonance (MR) imaging. Twelve specimens of gastric carcinoma were examined at 1.5-T using a small, loop surface coil. They were imaged within 2 days of fixation in formalin. The field of view was 30 mm; the matrix size was 256x256, and the section thickness was 2 mm. T1-weighted, T2-weighted and short inversion time inversion recovery (STIR) images were obtained. Two radiologists evaluated the MR images independently, and in discrepant cases, consensus was obtained through discussion. Findings on MR images were compared with histopathologic findings. All T1-weighted, T2-weighted and STIR images depicted the normal gastric wall as consisting of six layers. STIR images depicted normal six layers most clearly. Histologically, the cancerous invasion was found to extend into the mucosa in 4 of the 12 specimens, the submucosa in 3, the muscularis propria in 2, the subserosa in 2 and the serosa in 1. The grading by MR imaging matched the histopathologic findings for all 12 tumors. The overall accuracy was 100%. Thus, MR imaging in vitro was sufficiently accurate for grading cancerous invasion of the gastric wall.

Prognostic factors for early gastric cancer in France: Cox regression analysis of 332 cases

Early gastric cancer (EGC) is defined as a lesion in which the depth of invasion is limited to the mucosa, submucosa, or both regardless of lymph node status; moreover, it has an excellent prognosis, with a 5-year survival rate of more than 90%. We aimed to determine the prognostic factors for EGC in a large Western series. Over a 10-year period from January 1979 to December 1988 a series of 332 patients (mean age 64 years) with EGC were operated on in 23 centers (two French Associations for Surgical Research). The clinicopathologic data retrospectively and screened it for prognostic effect. The mean follow-up for the 332 EGC patients was 80 months. Postoperative mortality was 4% among 243 partial and 89 total gastric resections. The overall 5- and 7-year survival rates were 82% and 72%, respectively. The cumulative 5- and 7-year survival rates (mean follow-up 80 months) were 92.0% and 87.5%, respectively, excluding both operative and unrelated mortality. There was no significant difference in survival between partial and total gastric resection for lesions located in the lower third of the stomach ( p > 0.6). When survival data (excluding postoperative deaths) were analyzed using univariate analysis and Cox's proportional hazards model, lymphatic involvement ( p = 0.01), the site of the tumor in the upper two-thirds of the stomach ( p = 0.02), and submucosal lesions ( p = 0.049) showed a significant effect on predicting a poor prognosis. These results suggest that because of its prognostic value lymphadenectomy should be performed in addition to gastric resection for adequate classification of EGCs. Follow-up might be required only for patients with at least one poor prognostic factor.

Appropriate gastric resection with lymph node dissection for early gastric cancer

BACKGROUND

The extent of lymphadenectomy (limited vs. extended) and that of gastric resection (partial vs. total) remain controversial issues in the management of early gastric cancer (EGC). A multicentric study was performed to elucidate the appropriate gastric resection with lymph node dissection for early gastric cancer.

METHODS

From 1979 to 1988, 332 patients with EGC underwent surgery in 23 French centers. Clinicopathological data, the extent of resection, and the number of lymph nodes retrieved were reviewed retrospectively and screened for prognostic effect. The mean follow-up for the 332 EGC patients was 80 months.

RESULTS

Postoperative mortality was correlated to age (odds ratio [OR], 1.1) and extent of gastric resection (OR,10.3). Examination of survival data (excluding postoperative deaths) with univariate analysis and the Cox proportional hazards model showed that the independent factors for excellent prognosis included no lymphatic involvement (P =.005), 10 or more lymph nodes retrieved (P =.003), site of the tumor in the lower third of the stomach (P =.01), and mucosal lesions (P =.04). The extent of resection did not influence long-term survival.

CONCLUSIONS

Our results suggest that because of the associated good prognosis, the appropriate surgical treatment for EGC is partial gastrectomy with lymphadenectomy retrieving 10 or more lymph nodes.

Treatment and prognosis of early multiple gastric cancer

AIM

Early gastric cancer (EGC) may have a 5-year survival rate of over 90% following surgery. Early multifocal gastric cancer (EMGC) accounts for between 8.3 and 17% of all EGCs. A multicenter retrospective study is reported of prevalence, characteristics, prognosis and type of resection for EMGC patients.

METHOD

333 patients with EGC were operated on, between January 1979 and December 1988, and followed to June 1996.

RESULTS

33 EGC patients had EMGC. There was no significant difference in clinico-pathological features between EGC and EMGC. 21 cases of EMGC underwent a subtotal gastrectomy and 12 underwent a total gastrectomy. Recurrences after subtotal gastrectomy were, respectively, 10 and 18% for EGC and EMGC patients (p=0.2). The cumulative 5 years specific survival rate for 298 EGC and 34 EMGC were 94 and 90%, respectively (p=0.9). Five-year survival rates after subtotal gastrectomy were 92 and 90% for EGC and EMGC patients, respectively (p=0.8).

CONCLUSION

EGC and EMGC had the same clinico-pathological features and prognosis. A careful follow up of the stomach remnant is essential.