Rates and Risk Factors for Interval Gastric Cancers at Screening Gastroscopy

Abstract

Backgrounds/aims: Interval gastric cancers (GCs) can be encountered during screening gastroscopy. This study investigated the rate of interval GCs and their risk factors.

Materials and methods: We retrospectively investigated subjects who underwent screening gastroscopy from 2005 to 2017 in a university hospital and were diagnosed with GC. Subjects were grouped based on their endoscopic images and descriptive results into interval GC and initially diagnosed GC groups. Interval GCs were defined when endoscopic results within the previous 3 years were negative for GC. The clinico-pathological characteristics of the groups and risk factors for interval GCs were evaluated.

Results: Of 54 724 subjects who underwent screening gastroscopy, 234 were diagnosed with GC, of which 43 were interval GCs. The rate of interval GCs was 18.4% (43/234, mean age 61.6 years). Interval GCs were smaller than initially diagnosed GCs (1.6 vs 1.9 cm, P = .011). They were located in the low-to-mid-body in 44.2%, antrum in 48.8%, and high body and cardia in 7%. Their observation time was shorter (248.74 vs 410.64 sec, P = .032). In multivariate analysis, they were associated with short observation time (odds ratio [OR] 0.99, 95% CI 0.994-0.998, P < .001) and location in the low-to-mid-body (OR 2.12, 95% CI 1.071-4.181, P = .031), although differentiation, ulcerated type, metaplasia, Helicobacter pylori infection, and endoscopists' experience were not associated with interval GCs.

Conclusions: The rate of interval GCs was significant during screening gastroscopy. They might be reduced by increasing observation time, focusing on smaller lesions, and observing the low-to-mid-body of the stomach more carefully.

Figure 1.

(A and B) Endoscopic images of a typical true interval cancer: (A) Reddish nodular lesion was found on the posterior wall of the high body stomach during screening gastroscopy. Endoscopic resection revealed differentiated adenocarcinoma of 4 mm in size. (B) Previous endoscopy images had not shown any suspicious lesions at this location 2 years prior.

Figure 2.

(A and B) Endoscopic images of a typical missed cancer: (A) Slightly depressed lesion is found on the anterior wall of the gastric lower body. After endoscopic resection, the lesion was to be signet ring cell type intramucosal gastric cancer of 5 mm in size. (B) The previous endoscopic images 26 months prior had not included the same location of this lesion.

Figure 3.

(A and B) Endoscopic images of a typical unnoticed lesion: (A) A depressed lesion is shown at the gastric angle and was confirmed as differentiated adenocarcinoma by endoscopic resection. (B) The previous gastroscopy 3 years prior showed a slightly depressed lesion covered by mucus, indicating that the lesion could have been noticed if the mucosal visibility had been improved by washing the mucus away.

Figure 4.

(A-C) Endoscopic images of a typical case of insufficient biopsy. (A) Gastroscopy showing a small erosive lesion at the lesser curvature of the gastric antrum, confirmed as a differentiated adenocarcinoma by endoscopic resection. (B) The pathology report of the tissue biopsy was atypical epithelial cells 2 years prior, and (C) erosive gastritis 4 years prior.

Figure 5.

Flow chart of study population.

Figure 6.

The rate and cause of interval gastric cancer. True interval cancer, defined if endoscopic images had been taken at the location of a cancer lesion but no lesion had been found; missed cancer, defined if no endoscopic images had been made at the location of a cancer lesion; unnoticed cancer, defined if cancer lesions were visible in the earlier images but a biopsy was not performed; insufficient biopsy cases if the cancer was not diagnosed by biopsy.