Introduction

Corpus atrophic gastritis (CAG) requires endoscopic-histological surveillance due to the risk of developing gastric neoplastic lesions (GNL). This study aimed to identify variables associated with GNL development at long-term follow-up using a feature ranking method based on a novel One-Class Support Vector Machine (SVM) model.

Aims & Methods

A dataset containing clinical, endoscopic, and histological variables from consecutive CAG patients (2001-2023) adhering to a surveillance program was considered. GNL presence at the longest available follow-up was recorded. Gastric biopsies and histological evaluations were conducted according to the updated Sydney system. CAG patients with any missing data or a GNL diagnosis at the baseline gastroscopy were excluded from the final analysis. A Fisher score-based feature ranking method and One-Class SVM were used to select the optimal subset of baseline variables associated with GNL development, aiming to achieve average sensitivity (Se) and specificity (Sp) above 80%.

Results

Overall, 355 CAG patients were initially considered. Of these, 36 were excluded due to the presence of GNL at baseline gastroscopy, and 216 for missing data. Thus, a total of 103 patients were considered and grouped into: CAG patients with [22 patients (F 68.1%), median age 68 (35-83) years] and without GNL at follow-up [81 patients (F 72.8%), median age 59(26-84) years]. After a median follow-up of 60 (12-192) months, 13 epithelial GNL (gastric adenocarcinoma or high/low-grade dysplasia) and nine type-1 gastric-neuroendocrine-tumors (T1gNET) were recorded. Parietal-cell-antibodies and pepsinogen-I < 30 μg/l were associated with both epithelial GNL and T1gNET. Antral inflammation and age > 60 were linked to epithelial GNL, while anti-thyroperoxidase-antibodies, smoking, and dyspeptic symptoms at CAG diagnosis were linked to T1gNET. Low-dose aspirin and H. pylori eradication therapy showed inverse associations with epithelial GNL and T1gNET, respectively.

Conclusion

This is the first study in which an AI model simultaneously considers clinical, endoscopic, and histological characteristics from a dataset of CAG patients, showing good sensitivity and specificity in identifying those variables associated with developing GNL. Nonetheless, we acknowledge the need for improved variable standardization and data balancing between groups to enhance model performance further.

Introduction

Serrated lesions (SLs) in the proximal colon are increasingly recognized as important precursors to colorectal cancer (CRC), yet their detection remains challenging due to their flat morphology and subtle appearance. While chromoendoscopy using indigo carmine (IC) improves detection rates compared to white-light imaging (WLI), the utility of acetic acid-indigo carmine mixture (AIM)–based chromocolonoscopy remains unverified. This randomized controlled trial aimed to evaluate the efficacy of AIM compared to WLI and IC in detecting SLs in the proximal colon, with a focus on the impact of a second tandem examination.

Aims & Methods

In this multicenter, prospective, randomized controlled trial conducted at nine Japanese institutions, patients undergoing total colonoscopy were randomly assigned to three groups (WLI, IC, or AIM). All patients underwent a tandem examination of the proximal colon, defined as the region from the cecum to the hepatic flexure. The primary outcomes were the SL detection rate in the second observation (SDR2nd) and SL additional rate (SAR). Secondary outcomes included the detection and additional rates of other polys and factors contributing to SAR.

Results

A total of 1,319 patients were included in the per-protocol analysis. SDR2nd in the AIM group was significantly higher than that in the IC and WLI groups (14.0% vs. 7.9% vs. 2.7%, respectively). Similarly, ADR2nd was 24.7% in the AIM group, 22.2% in the IC group, and 10.5% in the WLI group. SAR was highest in the AIM group (69.3%), compared to 45.8% in IC and 22.4% in WLI. Multivariate logistic regression showed that AIM (OR 7.79, 95% CI: 3.76–17.08) and IC (OR 2.87, 95% CI: 1.37–6.28) were independently associated with improved SAR. GEE analysis indicated minimal interobserver variability. AIM also facilitated the detection of previously missed advanced SLs and sessile serrated polyposis syndrome (SPS), leading to changes in surveillance intervals.

Conclusion

AIM-based chromocolonoscopy significantly improves the detection of SLs in the proximal colon compared with IC and WLI. These findings support the incorporation of duplicate, contrast-enhanced examinations into routine colonoscopy practice and suggest AIM as a superior technique for detecting flat and mucus-covered SLs. Further studies are warranted to assess the long-term impact of improved SL detection on CRC incidence and mortality.

Introduction

Gastric mucosal visibility is essential for high-quality upper gastrointestinal (GI) endoscopy. While simethicone and N-acetylcysteine (NAC) have been shown to improve mucosal visibility, the optimal time interval between preparation and endoscopy remains undefined.

Aims & Methods

This randomized controlled trial evaluated the effect of timing on mucosal visibility and explored the upper limit beyond which visibility begins to decline.
In this single-center, randomized controlled trial, adult patients undergoing elective upper GI endoscopy were randomized into four groups: placebo, simethicone + NAC with endoscopy performed after 10–20 minutes, 20–30 minutes, and >30 minutes. The primary outcome was the proportion of patients achieving adequate gastric mucosal visibility (GMV), defined as a score of <7 on a validated visibility scale. A pre-specified subgroup analysis of the >30 minute group was performed by stratifying patients into 20-minute intervals (31–50, 51–70, and 71–90 minutes) to assess the durability of mucosal clarity over time.

Results

Comparison	Adequate gastric mucosal visibility (%)	P
10–20 min vs 20–30 min	27% vs 62%	0.001
10–20 min vs >30 min	27% vs 67%	0.001
10–20 min vs Placebo	27% vs 2.6%	0.001
20–30 min vs >30 min	62% vs 67%	0.174
20–30 min vs Placebo	62% vs 2.6%	0.001

1,140 patients (median age 42years, 63.2% males) were included in the study. Adequate GMV was significantly higher in all preparation groups compared to placebo (p < 0.001). The 20–30 minute and >30 minute groups demonstrated the highest rates of adequate visibility (61.5% and 73.5%, respectively), both significantly superior to the 10–20 minute group (26.9%) and placebo (2.6%). In the >30 minute subgroup analysis, the 31–50 minute interval demonstrated the highest adequacy (73.5%). The 51–70 minute group showed moderate adequacy (52.1%), which was not significantly different from the 20–30 minute group (p = 0.207). However, the 71–90 minute group had reduced adequacy (43.8%) and did not differ significantly from the 10–20 minute group (p = 0.145). No adverse events were reported across study arms.

Conclusion

Endoscopy performed between 20 and 50 minutes after mucosal preparation yields optimal gastric mucosal visibility. A decline in visibility beyond 50 minutes suggests a practical upper limit for endoscopy timing following preparation. These findings support structured, time-sensitive scheduling following mucosal cleansing to enhance procedural quality.

Disclosure

None