Differences in clinical features and morphology between differentiated and undifferentiated gastric cancer after Helicobacter pylori eradication

Endoscopic risk factors to inform early detection of gastric cancer after Helicobacter pylori eradication: Meta-analysis and systematic review

Objectives

Helicobacter pylori eradication reduces but cannot eliminate the risk of gastric cancer (GC). The prevalence of post-eradication GC has been rising. Characterization of the endoscopic findings of post-eradication GC may facilitate its early detection. We performed a meta-analysis and systematic review to clarify endoscopic risk factors to accelerate the early diagnosis of post-eradication GC.

Methods

Medline and PubMed were searched for randomized controlled trials, cohort studies, and case-control studies published in the English-language medical literature between January 1997 and July 2023. The included articles assessed the correlation between post-eradication GC and pre- and post-eradication endoscopic findings, and associated post-eradication GC with gastric atrophy, intestinal metaplasia (IM), map-like redness, and xanthoma.

Results

A total of 963 articles were retrieved. In these articles, 66 papers were finally included, comprising randomized controlled trials, cohort studies, and case-control studies. The included articles addressed gastric atrophy (16 studies), IM (eight studies), map-like redness (six studies), and xanthoma (two studies). Risk ratio (RR) of incident post-eradication GC was 3.40 (95%confidence interval [95%CI]: 1.98-5.84; p < 0.001) in cases of severe atrophy, 5.38 (95%CI: 3.62-8.00) in cases of severe IM, 2.34 (95%CI: 1.16-4.68) in cases with post-eradication map-like redness, and 2.75 (95% CI: 1.78-4.26) in cases with xanthoma.

Conclusions

Endoscopic atrophy, IM, and xanthoma observed at pre- and post-eradication time points and post-eradication map-like redness were suggested as endoscopic risk factors for post-eradication GC. Further studies are needed to clarify the risk of post-eradication GC based on these risk factors.

Comparison of Genetic Mutations of Gastric Cancer Diagnosed before or after Helicobacter pylori Eradication and between Differentiated and Undifferentiated Types Using Next-Generation Sequencing

INTRODUCTION

Genetic abnormalities specific to post-Helicobacter pylori eradication gastric cancer (GC), especially those associated with undifferentiated post-eradication GC, are unknown. We conducted next-generation sequencing of GC diagnosed either before or after eradication to investigate the carcinogenesis of post-eradication GC.

METHODS

Five cases of post-eradication differentiated GC [HP(-)-D group], five cases of H. pylori-positive differentiated GC [HP(+)-D group], four cases of post-eradication undifferentiated GC [HP(-)-U group], and six cases of H. pylori-positive undifferentiated GC [HP(+)-U group] underwent analysis. DNA was extracted from tumor samples, and non-tumor samples of all subjects. Next-generation target sequencing was conducted using the Ion AmpliSeq Library Kit 2.0 with the Ion AmpliSeq Cancer Hotspot Panel v2. Next-generation targeted sequencing results of the cancer part were subtracted from the results of the non-cancer part.

RESULTS

The HP(-)-D group displayed significantly fewer SNPs in hotspot than the other groups (p < 0.01). Definitive DNA mutations were identified by sequencing of cancerous and non-cancerous tissues. 5 of 20 patients had specific somatic mutations, with different TP53 mutations in the HP(+)-D and HP(-)-U groups, CTNNB1 mutations in the HP(+)-U group, and ATM mutations in the HP(+)-U group, but no mutations in the HP(-)-D group.

CONCLUSION

Several definite genetic mutations involved in GC were observed. Mutations were less frequent in post-eradication differentiated GC. However, because of small number of cases analyzed to identify carcinogenic differences, further analysis with a large number of cases and with strictly grading GC samples is needed.

INTRODUCTION

Genetic abnormalities specific to post-Helicobacter pylori eradication gastric cancer (GC), especially those associated with undifferentiated post-eradication GC, are unknown. We conducted next-generation sequencing of GC diagnosed either before or after eradication to investigate the carcinogenesis of post-eradication GC.

METHODS

Five cases of post-eradication differentiated GC [HP(-)-D group], five cases of H. pylori-positive differentiated GC [HP(+)-D group], four cases of post-eradication undifferentiated GC [HP(-)-U group], and six cases of H. pylori-positive undifferentiated GC [HP(+)-U group] underwent analysis. DNA was extracted from tumor samples, and non-tumor samples of all subjects. Next-generation target sequencing was conducted using the Ion AmpliSeq Library Kit 2.0 with the Ion AmpliSeq Cancer Hotspot Panel v2. Next-generation targeted sequencing results of the cancer part were subtracted from the results of the non-cancer part.

RESULTS

The HP(-)-D group displayed significantly fewer SNPs in hotspot than the other groups (p < 0.01). Definitive DNA mutations were identified by sequencing of cancerous and non-cancerous tissues. 5 of 20 patients had specific somatic mutations, with different TP53 mutations in the HP(+)-D and HP(-)-U groups, CTNNB1 mutations in the HP(+)-U group, and ATM mutations in the HP(+)-U group, but no mutations in the HP(-)-D group.

CONCLUSION

Several definite genetic mutations involved in GC were observed. Mutations were less frequent in post-eradication differentiated GC. However, because of small number of cases analyzed to identify carcinogenic differences, further analysis with a large number of cases and with strictly grading GC samples is needed.

Clinicopathologic Features of Early Gastric Cancer after Heli-cobacter pylori Eradication in Japanese Patients: Comparative Study between Early (<10 Years) and Late (>10 Years) Onset

BACKGROUND/OBJECTIVES

Eradication therapy for Helicobacter pylori gastritis was approved for insurance coverage by the Japanese government in 2013. Since then, the incidence of gastric cancer discovered after eradication (GCAE) has increased. However, there are only a few reports of GCAE diagnosed more than 10 years after eradication. We investigated the clinicopathological characteristics of early-stage GCAE, including histological types and the interval from eradication to diagnosis.

METHODS

Overall, 379 patients with a total of 448 GCAE lesions treated with endoscopic resection or surgery at our hospital between January 2015 and December 2021 were assessed, and 315 patients with a known interval from eradication to diagnosis of GCAE with a total of 354 lesions were included. We classified the cases into two groups: differentiated-type GCAE (D-GCAE; 279 patients, 318 lesions) and undifferentiated-type GCAE (UD-GCAE; 36 patients, 36 lesions).

RESULTS

Smoking and a mild-to-moderate degree of atrophy were risk factors associated with differentiated-type gastric cancer occurring more than 10 years after H. pylori eradication. Additionally, the rate of a mixture of histological types with relatively high malignant potential was significantly higher in UD-GCAE presenting more than 10 years after eradication group than those presenting within 10 years after eradication.

Multicenter study of invasive gastric cancer detected after 10 years of Helicobacter pylori eradication in Japan: Clinical, endoscopic, and histopathologic characteristics

OBJECTIVES

Gastric cancer can be diagnosed even in patients long after Helicobacter pylori eradication. Most cases involve intramucosal lesions; however, some are invasive and require surgery. To clarify appropriate long-term surveillance methods, this study compared invasive gastric cancer diagnosed ≥10 and <10 years after eradication.

METHODS

This retrospective multicenter study included 14 institutions. We included 377 patients with gastric cancer with submucosal or deep invasion after surgical or endoscopic resection. Ordered logistic regression analysis was used to explore the factors contributing to the pathological stage and histological type.

RESULTS

Invasive gastric cancer was detected in 84 patients (Group L) and 293 patients (Group S) ≥10 and <10 years after H. pylori eradication, respectively. Endoscopic mucosal atrophy at the time of cancer detection was similar in both groups; 50% of the patients had severe atrophy. Annual endoscopy correlated with early pathological stage (odds ratio [OR] 0.28, 95% confidence interval [CI] 0.14-0.54, p < 0.001). Group L exhibited an independent correlation with the advanced pathological stage (OR 2.27, 95% CI 1.06-4.88, p = 0.035) and the undifferentiated type (OR 2.12, 95% CI 1.16-3.90, p = 0.015). The pure differentiated type and early pathological stage significantly (p = 0.001) correlated with severe mucosal atrophy in Group S but not in Group L.

CONCLUSIONS

Invasive cancers diagnosed ≥10 years after H. pylori eradication were likely to be more malignant in histological type and pathological stage. Gastric cancer surveillance should continue regardless of endoscopic atrophy, particularly ≥10 years after eradication.