Gastric high-grade dysplasia can be associated with submucosal invasion: evaluation of its prevalence in a series of 121 endoscopically resected specimens

Unravelling interobserver variability in gastrointestinal glandular neoplasia: a contemporary study of US and Korean pathologists

AIMS

Interobserver variability in the assessment of gastric neoplasia biopsies between most Western and Eastern (predominantly represented by Japanese in the literature) pathologists has been documented. It is unknown if such variability exists between the US and Korean pathologists in the current era.

METHODS

Ten gastrointestinal (GI) pathologists from the USA (n=5) and South Korea (n=5) evaluated 100 scanned images of gastric (n=50) and colorectal (n=50) neoplasia biopsies and answered multiple questionnaires. Consensus was defined as the answer chosen by the majority. Cohen's (κc) and Fleiss' kappa (κf) values were calculated between the consensus of the two groups and among the raters, respectively.

RESULTS

Both groups reached a consensus in the majority of cases (74%-100%) with slight to perfect intergroup (κc=0.049-1.000) and no to substantial intragroup (κf=-0.083 to 0.660) agreements. For gastric neoplasia, Korean pathologists relied heavily on cytoarchitectural atypia, whereas the US pathologists focused on stromal invasion when diagnosing adenocarcinoma. For colorectal neoplasia, the Korean pathologists identified concurrent intramucosal carcinoma when diagnosing invasive adenocarcinoma, while the presence of desmoplasia was a prerequisite for the diagnosis of invasive adenocarcinoma for the US pathologists.

CONCLUSIONS

For GI neoplasia biopsy interpretation, the diagnostic approach of Korean pathologists is similar to that of Eastern/Japanese pathologists. Consensus outperformed kappa statistics in capturing the magnitude of inter-rater and intergroup reliability, highlighting the potential benefit of consensus meetings to decrease the gap between Western and Eastern diagnostic approaches.

Magnifying endoscopy with narrow-band imaging is useful in differentiating gastric cancer from matched adenoma in white light imaging

This study assessed the effect of magnifying endoscopy with narrow-band imaging (M-NBI) on the endoscopic differential diagnosis between intramucosal gastric carcinomas and adenomas with matched characteristics. Associations between magnified endoscopic findings and pathological high-grade cellular and architectural atypia were also investigated. In total, the records of 50 adenomas and 50 intramucosal well-differentiated adenocarcinomas matched by tumor size (≥ 20 mm or < 20 mm), shape (depression or non-depression), and color (red or non-red) were extracted. Fourteen endoscopists diagnosed adenoma or cancer in the 100 cases with conventional white light imaging (C-WLI), then did the same with C-WLI + M-NBI.The cancer diagnostic sensitivity, specificity, and accuracy were assessed. The sensitivity of C-WLI + M-NBI for cancer diagnosis was 79.9% compared to 71.6% with C-WLI (p < 0.001). There were no significant differences in specificity (40.1% vs. 36.3%, p = 0.296) and accuracy (55.9% vs. 58.1%, p = 0.163). High-grade cytological or architectural atypia was diagnosed more often with irregular microvascular pattern (IMVP) or microsurface pattern (IMSP), respectively, than the low-grade forms. In conclusion, IMVP and IMSP correlate with high-grade cytological and architectural atypia. M-NBI is useful in differentiating intramucosal carcinoma from adenoma and can reduce underdiagnosis of cancer.

Risk factor-based optimal endoscopic surveillance intervals after endoscopic submucosal dissection for gastric adenoma

To date, there exists no established endoscopic surveillance interval strategy after endoscopic submucosal dissection (ESD) for gastric adenoma. In this study, we suggest a risk factor-based statistical model for optimal surveillance intervals for gastric adenoma after ESD with curative resection. A cox proportional hazard model was applied to identify risk factors for recurrence after ESD. Patients (n = 698) were categorized into groups based on the identified risk factors. The cumulative density of recurrence over time was computed using a cubic splined baseline hazard function, and the customized surveillance interval was modeled for each risk group. The overall cumulative incidence of recurrence was 7.3% (n = 51). Risk factors associated with recurrence were male (hazard ratio [HR], 2.60, P = 0.030), protruded scar (HR, 3.18, P < 0.001), and age ≥ 59 years (HR, 1.05, P < 0.001). The surveillance interval for each group was developed by using the recurrence limit for the generated risk groups. According to the developed schedule, high-risk patients would have a maximum of seven surveillance visits for 5 years, whereas low-risk patients would have biennial surveillance for cancer screening. We proposed a simple and promising strategy for determining a better endoscopic surveillance interval by parameterizing diverse and group-specific recurrence risk factors into a well-known survival model.

The potential diagnostic significance of crypt differentiation in gastric dysplasia

AIMS

This study investigated the relationship between the differentiation of tumour cells into crypts, which is determined by cell differentiation into Paneth and neuroendocrine cells, and tumour infiltration in gastric dysplasia.

METHODS AND RESULTS

The lesions were endoscopically biopsied low-grade dysplasia (LGD), endoscopically resected high-grade dysplasia (HGD), or cancer with submucosal invasion. LGD (n = 32) displayed crypt differentiation across the entire width of the tumour in all cases. Crypt differentiation was identified as a characteristic of tumours with low biological malignancy. HGD (n = 40) included tumours with a mixture of areas with and without crypt differentiation (n = 25) and tumours with crypt differentiation throughout the entire width (n = 15). Of the cancers with submucosal invasion (n = 30), the morphological progression of HGD area with crypt differentiation, HGD area without crypt differentiation and invasive cancer without crypt differentiation was confirmed for 23 samples. In two lesions, invasive cancer without crypt differentiation developed from HGD without crypt differentiation throughout the tumour width. In five samples, well-differentiated tubular adenocarcinoma with crypt differentiation developed from HGD with crypt differentiation and invaded with lamina propria-like stroma.

CONCLUSIONS

Loss of crypt differentiation could be an objective indicator of infiltration in the progression of HGD to invasive cancer. The invasive potential of dysplasia depends on the presence or absence of crypt differentiation.

Efficacy of Endoscopic Submucosal Dissection for Superficial Gastric Neoplasia in a Large Cohort in North America

BACKGROUND & AIMS

Endoscopic submucosal dissection (ESD) is a widely accepted treatment option for superficial gastric neoplasia in Asia, but there are few data on outcomes of gastric ESD from North America. We aimed to evaluate the safety and efficacy of gastric ESD in North America.

METHODS

We analyzed data from 347 patients who underwent gastric ESD at 25 centers, from 2010 through 2019. We collected data on patient demographics, lesion characteristics, procedure details and related adverse events, treatment outcomes, local recurrence, and vital status at the last follow up. For the 277 patients with available follow-up data, the median interval between initial ESD and last clinical or endoscopic evaluation was 364 days. The primary endpoint was the rate of en bloc and R0 resection. Secondary outcomes included curative resection, rates of adverse events and recurrence, and gastric cancer-related death.

RESULTS

Ninety patients (26%) had low-grade adenomas or dysplasia, 82 patients (24%) had high-grade dysplasia, 139 patients (40%) had early gastric cancer, and 36 patients (10%) had neuroendocrine tumors. Proportions of en bloc and R0 resection for all lesions were 92%/82%, for early gastric cancers were 94%/75%, for adenomas and low-grade dysplasia were 93%/ 92%, for high-grade dysplasia were 89%/ 87%, and for neuroendocrine tumors were 92%/75%. Intraprocedural perforation occurred in 6.6% of patients; 82% of these were treated successfully with endoscopic therapy. Delayed bleeding occurred in 2.6% of patients. No delayed perforation or procedure-related deaths were observed. There were local recurrences in 3.9% of cases; all occurred after non-curative ESD resection. Metachronous lesions were identified in 14 patients (6.9%). One of 277 patients with clinical follow up died of metachronous gastric cancer that occurred 2.5 years after the initial ESD.

CONCLUSIONS

ESD is a highly effective treatment for superficial gastric neoplasia and should be considered as a viable option for patients in North America. The risk of local recurrence is low and occurs exclusively after non-curative resection. Careful endoscopic surveillance is necessary to identify and treat metachronous lesions.

Clinicopathological characteristics of Epstein-Barr virus and microsatellite instability subtypes of early gastric neoplasms classified by the Japanese and the World Health Organization criteria

Gastric cancer is a heterogenous disease with different phenotypes, genotypes, and clinical outcomes, including sensitivity to treatments and prognoses. Recent medical advances have enabled the classification of this heterogenous disease into several groups and the consequent analysis of their clinicopathological characteristics. Gastric cancer associated with Epstein–Barr virus (EBV) and microsatellite‐unstable tumors are considered to be the two major subtypes as they are clearly defined by well‐established methodologies, such as in situ hybridization and polymerase chain reaction‐based analyses, respectively. However, discrepancies in the histological diagnosis of gastric neoplasms remain problematic, and international harmonization should be performed to improve our understanding of gastric carcinogenesis. We re‐evaluated Japanese cases of early gastric cancer according to the current World Health Organization (WHO) criteria and classified them into genomic subtypes based on microsatellite instability (MSI) and EBV positivity to determine the initial genetic events in gastric carcinogenesis. A total of 113 Japanese early gastric cancers (including low‐ and high‐grade dysplasias) treated with endoscopic resection over 5 years were archived in our hospital. A histological re‐evaluation according to the WHO criteria revealed 54 adenocarcinomas, which were divided into 6 EBV‐positive (11.1%), 7 MSI‐high (MSI‐H, 13.0%), and 41 microsatellite stable cases (75.9%). MSI‐H adenocarcinoma was confirmed by an immunohistochemistry assay of mismatch repair proteins. Programmed death‐ligand 1 immunostaining with two antibodies (E1L3N and SP263) was positive in tumor cells of one MSI‐H adenocarcinoma case (1/7, 14.3%). The proportion of stained cells was higher with clone SP263 than with E1L3N. Histologically, EBV‐positive carcinomas were poorly differentiated (83.8%), and MSI‐H cancers were frequent in well to moderately differentiated adenocarcinoma (85.7%), indicating that the EBV‐positive subtype presented with high‐grade morphology even when an early lesion. Our study indicates that the WHO criteria are useful for subdividing Japanese early gastric cancers, and this subdivision may be useful for comparative analysis of precursor lesions and early carcinoma.

Cell polarity (the 'four lines') distinguishes gastric dysplasia from epithelial changes in reactive gastropathy

AIMS

Gastric dysplasia is a risk factor for synchronous and subsequent gastric carcinoma. Distinguishing gastric dysplasia from reactive changes is subject to interobserver disagreement and is a frequent reason for expert consultation. We previously used assessment of surface cell polarity (the 'four lines') as a key feature to decrease equivocal diagnoses in Barrett oesophagus. In the current study, we examined for the presence or absence of the four lines in gastric dysplasia and reactive gastropathy.

MATERIALS AND METHODS

The study includes all (n = 91) in-house biopsies with at least gastric dysplasia from the surgical pathology archives of two academic institutions during a 5-year period from 2008 to 2012. A reactive gastropathy group (n = 60) was created for comparison.

RESULTS

The dysplasia/neoplasia group was comprised of 14 biopsies of gastric foveolar-type dysplasia, 59 of intestinal-type dysplasia, 14 with dysplasia in fundic gland polyps, three pyloric gland adenomas and one oxyntic gland adenoma. Loss of surface cell polarity was seen in all 88 dysplasia cases with evaluable surface epithelium. All 57 reactive gastropathy cases with evaluable surface epithelium showed intact surface cell polarity except in focal areas directly adjacent to erosions in 17 cases, where the thin wisp of residual surface mucin could not be appreciated on haematoxylin and eosin.

CONCLUSION

Surface cell polarity (the four lines) was lost in all gastric dysplasia biopsies with evaluable surface epithelium and maintained in all biopsies of reactive gastropathy. Caution should be taken in using this feature adjacent to erosions in reactive gastropathy.

Analysis of clinicopathological and molecular features of crawling-type gastric adenocarcinoma

BACKGROUND

Crawling-type adenocarcinoma (CRA) is an important gastric cancer (GC) subtype that exhibits a specific histological pattern and has characteristic clinicopathological findings. Despite its characteristic histology, little is known about the molecular characteristics of CRA.

METHODS

We examined 177 GC cases, including 51 cases of CRA and 126 cases having conventional differentiated adenocarcinomas (CDAs). Results for immunohistochemistry (mucin phenotype; Muc5AC, Muc6, Muc2 and CD10, CDX-2, MLH-1, p53 and β-catenin), mutation analysis (TP53, KRAS and BRAF), microsatellite instability (BAT25, BAT26, D2S123, D5S346 and D17S250), DNA methylation status by a two-panel method (RUNX3, MINT31, LOX, NEUROG1, ELMO1 and THBD), MLH-1 promoter methylation, and allelic imbalance (AI; 1p, 3p, 4p, 5q, 8p, 9p, 13q, TP53, 18q and 22q) were examined.

RESULTS

CRAs were more likely to occur in the middle third of the stomach, in younger patients and to be macroscopically depressed. Nuclear accumulation of β-catenin and loss of MLH-1 expression were less frequent among CRA cases compared to CDA cases. At a molecular level, CRA is often characterized by the deletion mutation c.529_546 (18-base pair deletion at codon 177-182 in exon 5) in the TP53 gene (10 cases). Although the low methylation epigenotype was significantly more frequent for CRAs compared to CDAs, multiple AIs were more often seen in CRAs relative to CDAs.

CONCLUSIONS

The results demonstrated that TP53 mutations, particularly c.529_546del, and multiple AIs are closely associated with CRA carcinogenesis. Our results suggest that CRA is an independent entity of GC in terms of clinicopathologic and molecular findings.

Increased incidence of metachronous gastric neoplasm after endoscopic resection in patients with synchronous gastric neoplasm

Background

Recurrence risk is a major concern after endoscopic resection (ER) of gastric neoplasms. This study was to compare metachronous risk in patients with and without synchronous neoplasms after complete ER.

Methods

After ER for gastric neoplasms, patients were divided into those with and without synchronous neoplasm. The metachronous risk of gastric neoplasms was compared between the two groups.

Results

After ER of 678 cancers and 891 adenomas, synchronous neoplasm was found in 11.8% of cancers and 11.4% of adenomas. In the multiple (n = 182) and the single group (n = 1387), metachronous neoplasms occurred in 18.1 and 8.6%, respectively (HR 2.40; 95% CI, 1.62–3.34). When the pathology of the recurred lesion was limited to cancer, metachronous risk was also significantly higher in the multiple than in the single group (HR, 2.2; 95% CI, 1.17–3.85). In the recurred pathology of the multiple group, cancer development was frequently observed in patients with cancer compared to those with only adenomas in the synchronous lesion (67.0% vs. 13.0%, respectively; P = 0.023).

Conclusions

This study demonstrated that metachronous risk was significantly higher in patients with synchronous gastric neoplasms after ER. Therefore, meticulous examination is important in patients with synchronous neoplasm.

Long-term outcomes of patients with gastric adenoma in Korea: A retrospective observational study

New endoscopic resection techniques are constantly being developed for gastric adenoma, which can be classified as low or high grade according to the Vienna classification. However, long-term data on gastric adenoma (e.g., removal or follow-up after resection via endoscopy) remain lacking.We retrospectively analyzed 133 cases with gastric adenoma that underwent endoscopic resection from January 2010 to November 2018. We analyzed the risk factors and frequency of patients with synchronous and metachronous lesions after endoscopic resection for gastric adenoma and followed them for more than 2 years.One hundred six (79.7%) and 27 patients (20.3%) received endoscopic resection (ER) once and more than twice, respectively. Compared with the initial endoscopic biopsy pathological results, the upgraded and downgraded histological discrepancy rates were 10.5% (n = 14) and 3.0% (n = 4) after resection, respectively. The mean time to synchronous/metachronous recurrence was 2.23 years. The average lesion size at first procedure was larger in the multiple ER group than in the single ER group (2.00 vs 1.10 cm; P = .040). Eleven (8.3%) and 16 patients (12.0%) had recurred synchronous and metachronous lesions, respectively. In the multivariate Cox analysis of the recurrence group, intestinal metaplasia (hazard ratio, 2.761; 95% confidence interval, 1.117-6.820; P = .028) and lesion size (hazard ratio, 1.607; 95% confidence interval, 1.082-2.385; P = .019) were independent factors for receiving endoscopic resection more than twice.If patients have severe intestinal metaplasia or large size of lesion at endoscopic resection for gastric adenoma, periodic observation is necessary.

Low Frequency of Lymph Node Metastases in Patients in the United States With Early-stage Gastric Cancers That Fulfill Japanese Endoscopic Resection Criteria

BACKGROUND & AIMS

In the West, early gastric cancer is increasingly managed with endoscopic resection (ER). This is, however, based on the assumption that the low prevalence and risk of lymph node metastases observed in Asian patients is applicable to patients in the United States. We sought to evaluate the frequency of and factors associated with metastasis of early gastric cancers to lymph nodes, and whether the Japanese ER criteria are applicable to patients in the US.

METHODS

We performed a retrospective study of 176 patients (mean age 68.5 years; 59.1% male; 58.5% white) who underwent surgical resection with lymph node dissection of T1 and Tis gastric adenocarcinomas, staged by pathologists, at 7 tertiary care centers in the US from January 1, 1999, through December 31, 2016. The frequency of lymph node metastases and associated risk factors were determined.

RESULTS

The mean size of gastric adenocarcinomas was 23.0 ± 16.6 mm-most were located in the lower-third of the stomach (67.0%), invading the submucosa (55.1%), and moderately differentiated (31.3%). Lymphovascular invasion was observed in 18.2% of lesions. Overall, 20.5% of patients had lymph node metastases. Submucosal invasion (odds ratio, 3.9; 95% CI, 1.4-10.7) and lymphovascular invasion (odds ratio, 4.6; 95% CI, 1.8-12.0) were independently associated with increased risk of metastasis to lymph nodes. The frequency of lymph node metastases among patients fulfilling standard and expanded Japanese criteria for ER were 0 and 7.5%, respectively.

CONCLUSIONS

The frequency of lymph node metastases among patients with early gastric cancer in a US population is higher than that of published Asian series. However, early gastric cancer lesions that meet the Japanese standard criteria for ER are associated with negligible risk of metastasis to lymph nodes, so ER can be recommended for definitive therapy. Expanded criteria cancers appear to have a higher risk of metastasis to lymph nodes, so ER may be considered for select cases.

RHOA mutations and CLDN18-ARHGAP fusions in intestinal-type adenocarcinoma with anastomosing glands of the stomach

A subtype of intestinal-type adenocarcinoma of the stomach, characterized by low-grade cytological atypia and anastomosing glands, has been described in several reports under different names. One of the remarkable features of these lesions, herein referred to as intestinal-type adenocarcinoma with anastomosing glands, is the frequent association of poorly differentiated adenocarcinoma components. Here we analyzed 44 intestinal-type adenocarcinomas with anastomosing glands focusing on the molecular abnormalities that are common in diffuse-type gastric cancers. Next-generation sequencing identified RHOA and CDH1 mutations in 22 (50%) and one lesion (2%), respectively. Reverse transcription-PCR detected CLDN18-ARHGAP fusions in three lesions (7%). Immunohistochemically, none of the lesions showed abnormal p53 expression patterns whereas focal and diffuse loss of ARID1A was observed in four and one lesion, respectively. Examination of 37 lesions of dysplasia and 26 usual-type intramucosal adenocarcinomas identified one RHOA mutation in adenocarcinoma and no CLDN18-ARHGAP fusions, indicating that these genetic alterations are highly specific to intestinal-type adenocarcinomas with anastomosing glands among differentiated-type intramucosal neoplasms. The present study showed that intestinal-type adenocarcinoma with anastomosing glands represents a genetically distinct group of tumors with the frequent presence of RHOA mutations and CLDN18-ARHGAP fusions, which are thought to be specific to diffuse-type gastric cancers.

Calcium Carbonate Nanoparticles Can Activate the Epithelial⁻Mesenchymal Transition in an Experimental Gastric Cancer Model

Previously, we have shown the possibility of intramucosal gastric carcinoma induction by the intragastric administration of a mixture of formaldehyde and hydrogen peroxide in rats. In this study, we report a sizable increase in carcinogenic properties of the mixture when a suspension containing calcium carbonate nanoparticles was added to it. This technique allowed us to reduce both the number of the carcinogen administrations from twelve to two and the time to the cancer induction from six to four months. Although the induced tumors were represented by the intramucosal carcinomas, they were characterized by the extensive invasion of individual tumor cells and their clusters into the muscle layer and serosa as well as into the omentum and blood vessels. Considering that the invasive tumor cells were positive for vimentin, Snail and TGF-β2, we concluded that their invasion was the result of the activation of epithelial–mesenchymal transition (EMT) mechanisms. Thus, taking into account the data obtained, it can be assumed that under the conditions of inflammation or carcinogenesis, the calcium carbonate nanoparticles may affect the activation of EMT mechanisms.

Endoscopic and clinicopathological features of intramucosal, histologically mixed-type, low-grade, well-differentiated gastric tubular adenocarcinoma with the potential for late-onset lymph node metastasis

BACKGROUND

Intramucosal, histologically mixed-type, low-grade (LG), well-differentiated gastric tubular adenocarcinomas (tub1s; LG-tub1s) have larger mean diameters and exhibit a higher frequency of the gastric mucin phenotype (G-phenotype) than pure LG-tub1s. In proportion to their increases in diameter, G-phenotype differentiated-type early gastric cancer (EGC) tumours reportedly grow to eventually contain (an) undifferentiated-type component(s) and LG-tub1s, which are included in differentiated-type EGCs, reportedly exhibit changes in their glandular architectural and cytological atypia grades from LG to high-grade (HG) and can grow to contain a moderately differentiated tubular adenocarcinoma (tub2) component and undifferentiated components. Because they generally show a higher frequency of malignancy relative to tumours with a higher atypia grade and lower differentiation degree, it is suggested that, among mixed-type LG-tub1s, G-phenotype LG-tub1s containing an HG-tub2 component (LG-tub1s > HG-tub2) with undifferentiated components might lead to late-onset metastasis to lymph nodes even after a successful endoscopic submucosal dissection (ESD). We aimed to clarify the endoscopic and clinicopathological features of these G-phenotype LG-tub1s > HG-tub2.

METHODS

Of the 13,217 oesophagogastroduodenoscopies performed at our institutions between September 2008 and March 2016, 185 EGC lesions were evaluated in this retrospective observational study. Among these EGC lesions, 60 intramucosal LG-tub1s were divided into 53 tub1 (44 pure LG-tub1s and nine LG-tub1s containing HG-tub1) lesions and seven LG-tub1 > tub2 (LG-tub1 containing LG- and HG-tub2) lesions.

RESULTS

The frequencies of the superficial depressed type (P = 0.026), reddish colour (P = 0.006), HG of contained tub2s (P = 0.006), and G-phenotype (P = 0.028) were significantly higher in the LG-tub1 > tub2 group than those in the tub1 group. However, the largest lesion of the LG-tub1 > tub2 group had a superficial flat appearance, an isochromatic colour, an HG-tub2 and an undifferentiated component, and a large diameter greater than 30 mm, and it exhibited a G-phenotype.

CONCLUSIONS

Intramucosal G-phenotype LG-tub1s > HG-tub2 are potential premalignant stomach neoplasms that may have specific endoscopic and clinicopathological features. However, G-phenotype LG-tub1s > HG-tub2 with undifferentiated component, which potentially show higher malignancy than those without undifferentiated components might change from a reddish to isochromatic colour. Accurately diagnosing, treating, and following-up G-phenotype LG-tub1s > HG-tub2 might decrease the number of patients who experience late-onset metastasis after ESD.

Molecular profiling and comprehensive genome-wide analysis of somatic copy number alterations in gastric intramucosal neoplasias based on microsatellite status

BACKGROUND

We attempted to identify the molecular profiles of gastric intramucosal neoplasia (IMN; low-grade dysplasia, LGD; high-grade dysplasia, HGD; intramucosal cancer, IMC) by assessing somatic copy number alterations (SCNAs) stratified by microsatellite status (microsatellite stable, MSS; microsatellite instable, MSI). Thus, microsatellite status was determined in 84 tumors with MSS status and 16 tumors with MSI status.

METHODS

One hundred differentiated type IMNs were examined using SCNAs. In addition, genetic mutations (KRAS, BRAF, PIK3CA, and TP53) and DNA methylation status (low, intermediate and high) were also analyzed. Finally, we attempted to identify molecular profiles using a hierarchical clustering analysis.

RESULTS

Three patterns could be categorized according to SCNAs in IMNs with the MSS phenotype: subgroups 1 and 2 showing a high frequency of SCNAs, and subgroup 3 displaying a low frequency of SCNAs (subgroup 1 > 2 > 3 for SCNA). Subgroup 1 could be distinguished from subgroup 2 by the numbers of total SCNAs (gains and losses) and SCN gains (subgroup 1 > 2). The SCNA pattern of LGD was different from that of HGD and IMC. Moreover, IMNs with the MSI phenotype could be categorized into two subtypes: high frequency of SCNAs and low frequency of SCNAs. Genetic mutations and DNA methylation status did not differ among subgroups in IMNs.

CONCLUSION

Molecular profiles stratified by SCNAs based on microsatellite status may be useful for elucidation of the mechanisms of early gastric carcinogenesis.

Differences in Prevalence of Lymphovascular Invasion among Early Gastric Cancers between Korea and Japan

BACKGROUND/AIMS

The presence of invasion is a diagnostic criterion of early gastric cancer (EGC) in Korea, whereas diagnosis in Japan is based on enlarged nuclei and prominent nucleoli. Moreover, the depth of invasion is the location of cancer cell infiltration in Korea, whereas it is the location of lymphovascular invasion (LVI) or cancer cell infiltration in Japan. We evaluated the characteristics of EGC with LVI to uncover the effects of different diagnostic criteria.

METHODS

Consecutive T1-stage EGC patients who underwent complete resection were included after endoscopic or surgical resection. The presence of LVI was evaluated.

RESULTS

LVI was present in 112 of 1,089 T1-stage EGC patients. LVI was associated with depth of invasion (p<0.001) and age (p=0.017). The prevalence of LVI in mucosal cancer was significantly higher in Korea (p<0.001), whereas that of submucosal cancer was higher in Japan (p=0.024). For mucosal EGC types, LVI was positively correlated with diagnostic criteria applied in Korea (p=0.017). For submucosal EGC types, LVI was positively correlated with Japanese criteria (p=0.001) and old age (p=0.045).

CONCLUSIONS

The higher prevalence of LVI for mucosal EGC in Korea and for submucosal EGC in Japan indicates that different diagnostic criteria should be considered when reading publications from other countries.

Genetic differences stratified by PCR-based microsatellite analysis in gastric intramucosal neoplasia

BACKGROUND

Although genetic alterations in patients with advanced gastric cancer have been extensively studied, those in patients with intramucosal neoplasia (IMN) are still poorly understood.

METHODS

We evaluated genetic differences in 158 IMNs, including 51 low-grade dysplasias, 58 high-grade dysplasias (HGDs), 30 intramucosal cancers (IMCs), and 19 mixed tumors (composed of IMC and HGD within the same tumor), using PCR-based microsatellite analysis [allelic imbalance (AI) and microsatellite instability (MSI)]. We classified the DNA methylation status as a hypermethylated epigenome, a moderately methylated epigenome, or a hypomethylated epigenome. In addition, p53 overexpression, β-catenin nuclear localization, and mucin expression were also examined.

RESULTS

From cluster analysis, the IMNs examined were categorized into four subgroups as follows. Tumors in subgroup 1 were characterized by MSI-high status, a hypermethylated epigenome, and loss or reduction of expression of MLH-1. Tumors in subgroup 2 showed a mixed pattern consisting of AI and MSI. In contrast, tumors in subgroup 3, which showed accumulation of multiple AIs, were closely associated with HGD, IMC, or mixed tumor and exhibited nuclear expression of β-catenin. Tumors in subgroup 4, which were generally low-grade dysplasias, exhibited a low frequency of AIs and no MSI. Although the mucin phenotype was not correlated with any subgroup, expression of mucin was associated with some subgroups. Overexpression of p53 was common in all subgroups.

CONCLUSION

The approach described herein was useful for studying genetic differences in IMNs. In addition, we suggest that stratification of genetic differences may help to identify genetic molecular profiles in IMNs.

Practical Points in Gastric Pathology

CONTEXT

-The diagnosis of gastric epithelial lesions is difficult in clinical practice, even with the recent developments and advances in endoscopic modalities, owing to the diverse morphologic features of the lesions, lack of standardized diagnostic criteria, and the high intraobserver and interobserver variabilities in the nonneoplastic (regenerative)-neoplastic spectrum.

OBJECTIVE

-To provide an overview of the current concepts and unresolved issues surrounding the diagnosis of diseases in the nonneoplastic-neoplastic spectrum, and to discuss some noteworthy properties and histologic features of gastric epithelial lesions.

DATA SOURCES

-A comprehensive assessment of the medical literature on gastric epithelial lesions was performed; we also interjected our own experiences into the discussion. Sources included original studies, review articles, and textbooks related to the field.

CONCLUSIONS

-Our literature review revealed that clear cell changes and micropapillary carcinoma components in gastric carcinomas are associated with poor clinical outcomes and should hence be included in pathologic reports. Moreover, we suggest a stepwise biopsy-endoscopic resection modality for the diagnosis of borderline neoplasia-nonneoplasia cases.

Body mass index, serum total cholesterol, and risk of gastric high-grade dysplasia: A case-control study among Chinese adults

Obesity is related to an increased risk of gastric cardia cancer. However, the influences of excess body weight and serum total cholesterol on the risk of gastric high-grade dysplasia have not been fully characterized.A case-control study was conducted to explore the relationships between body mass index (BMI), serum total cholesterol level, and the risk of gastric high-grade dysplasia in Chinese adults. A total of 893 consecutive patients with gastric high-grade dysplasia (537 men and 356 women) and 902 controls (543 men and 359 women) were enrolled from January 2000 to October 2015. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated, and a multivariate analysis was conducted.After adjusting for age, alcohol consumption, smoking status, family history of gastric cancer or esophageal cancer, and serum total cholesterol level, a BMI ranging from 27.5 to 29.9 was significantly related to an increased risk of gastric high-grade dysplasia in both men (adjusted OR = 1.87, 95% CI = 1.24-2.81) and women (adjusted OR = 2.72, 95% CI = 1.44-5.16). The 2 highest BMI categories (27.5-29.9 and ≥30.0) were identified as risk factors for gastric cardia high-grade dysplasia in both men (BMI = 27.5-29.9: adjusted OR = 1.78, 95% CI = 1.02-3.10; BMI ≥ 30.0: adjusted OR = 2.54, 95% CI = 1.27-5.08) and women (BMI = 27.5-29.9: adjusted OR = 2.88, 95% CI = 1.27-6.55; BMI ≥ 30.0: adjusted OR = 2.77, 95% CI = 1.36-5.64), whereas only a BMI ranging from 27.5 to 29.9 was a risk factor for gastric noncardia high-grade dysplasia in both men (adjusted OR = 1.98, 95% CI = 1.25-3.14) and women (adjusted OR = 2.88, 95% CI = 1.43-5.81). In addition, higher serum total cholesterol was associated with an increased risk of gastric noncardia high-grade dysplasia (adjusted OR = 1.83, 95% CI = 1.25-2.69) in women.Increased BMI was associated with an increased risk of gastric high-grade dysplasia in both men and women, and higher serum total cholesterol increased the risk of gastric noncardia high-grade dysplasia in women.

Morphological Characteristics of Early Gastric Neoplasms Detected After Helicobacter pylori Eradication

BACKGROUND

Previous morphological studies indicated that the eradication of Helicobacter pylori (H. pylori) made gastric neoplasms endoscopically indistinct through the flattening and covering of tumors with a non-neoplastic epithelium (NE).

AIM

To validate these alterations.

METHODS

We reviewed and compared the endoscopic and histological findings of early gastric carcinomas and high-grade dysplasias resected endoscopically from H. pylori-infected and H. pylori-eradicated patients. The extent of NE covering a tumor was expressed as the histological length ratio of NE to the tumor. Tumor morphology was compared before and after therapies in patients who received H. pylori eradication treatments during the period from tumor discovery to endoscopic resection.

RESULTS

NE-covered ratios were higher in the 59 tumors detected after the eradication of H. pylori than in the 152 tumors detected during the infection (median 8 vs. 0 %, respectively), whereas the frequency at which an elevated morphology and whitish discoloration of a tumor were observed was less (14 vs. 56 %, and 14 vs. 43 %, respectively). These were also independent characteristics for tumors detected after the eradication of H. pylori. Two elevated tumors showing whitish discoloration out of 16 tumors became endoscopically indistinct following H. pylori eradication treatments through the flattening of tumors and muting of the discoloration.

CONCLUSION

The eradication of H. pylori promoted covering with NE, the flattening of tumors, and muting of the whitish discoloration, which may make a subset of tumors, potentially including whitish elevated neoplasms, indistinct.

Incidence of gastric cancer after endoscopic resection of gastric adenoma

BACKGROUND AND AIMS

The annual incidence of metachronous cancer after endoscopic resection (ER) of early gastric cancer (EGC) is approximately 3%. However, the incidence of gastric cancer after ER of a gastric adenoma is not known. The aim of this study was to determine whether the incidence of gastric cancer after ER of a gastric adenoma was different compared with that of metachronous cancer after ER of EGC.

METHODS

We retrospectively analyzed data from patients who underwent ER for gastric neoplasia from January 2005 to August 2013. Enrolled patients were divided into 2 groups: patients with low-grade dysplasia were included in the adenoma group and patients with high-grade dysplasia or invasive neoplasia were included in the EGC group. The main outcome was the incidence of gastric cancer after ER.

RESULTS

At a median follow-up of 28 months, gastric cancer newly developed in 13 adenoma patients (3.6%) and in 30 EGC patients (5.1%). The incidence rate of gastric cancer after ER was 14.4 cases per 1000 person-years in adenoma patients and 18.4 cases per 1000 person-years in EGC patients (P = .309 by the log-rank test). The hazard ratio of metachronous neoplasia in adenoma patients compared with EGC patients was 0.97 (95% confidence interval, 0.62-1.53). Metachronous tumors with invasion beyond the muscularis mucosa were more frequent in adenoma patients than in EGC patients (7/35 [20.0%] vs 3/63 [4.8%], P = .017).

CONCLUSION

The incidence of gastric cancer after ER for gastric adenoma was not significantly different from that of EGC. If further prospective studies confirm these findings, careful endoscopic surveillance with the same level of intensity should be considered for both gastric adenoma and EGC patients after ER.

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.

The Japanese Viewpoint on the Histopathology of Early Gastric Cancer

Japanese histopathologists have traditionally had greater opportunity to study the histology and clinical course of early gastric cancer because of technological developments including double contrast radiography and endoscopy systems, combined with the higher incidence of gastric cancer in the general population in Japan. Endoscopic resection is now considered best practice for treatment of early gastric cancers with a negligible risk of lymph node metastasis. Histopathologic evaluation plays a critical role in assessing the likelihood of lymph node metastasis on endoscopically resected specimens. There remains disparity between Western and Japanese histopathologists in the conceptual approach to the histopathologic evaluation of neoplastic lesions in the upper gastrointestinal tract, in particular regarding lesions straddling the borderline between noninvasive and invasive disease. Although in routine practice, the clinical impact of these conceptual differences is small, this disparity does complicate international exchange of datasets and the development of globally applicable formal definitions. Here we review the current practice in histological diagnosis of early gastric cancer in Japan and discuss some of the conceptual differences between Japanese and Western histopathological assessment of lesions in the neoplastic stomach.