Early gastric cancer detection in high-risk patients: a multicentre randomised controlled trial on the effect of second-generation narrow band imaging

Abstract

Objective: Early detection of gastric cancer has been the topic of major efforts in high prevalence areas. Whether advanced imaging methods, such as second-generation narrow band imaging (2G-NBI) can improve early detection, is unknown.

Design: This open-label, randomised, controlled tandem trial was conducted in 13 hospitals. Patients at increased risk for gastric cancer were randomly assigned to primary white light imaging (WLI) followed by secondary 2G-NBI (WLI group: n=2258) and primary 2G-NBI followed by secondary WLI (2G-NBI group: n=2265) performed by the same examiner. Suspected early gastric cancer (EGC) lesions in both groups were biopsied. Primary endpoint was the rate of EGC patients in the primary examination. The main secondary endpoint was the positive predictive value (PPV) for EGC in suspicious lesions detected (primary examination).

Results: EGCs were found in 44 (1.9%) and 53 (2.3%; p=0.412) patients in the WLI and 2G-NBI groups, respectively, during primary EGD. In a post hoc analysis, the overall rate of lesions detected at the second examination was 25% (n=36/145), with no significant differences between groups. PPV for EGC in suspicious lesions was 13.5% and 20.9% in the WLI (50/371 target lesions) and 2G-NBI groups (59/282 target lesions), respectively (p=0.015).

Conclusion: The overall sensitivity of primary endoscopy for the detection of EGC in high-risk patients was only 75% and should be improved. 2G-NBI did not increase EGC detection rate over conventional WLI. The impact of a slightly better PPV of 2G-NBI has to be evaluated further.

Trial registration number: UMIN000014503.

Keywords: endoscopy; gastric cancer; screening; surveillance.

Figure 1

Representative images of target lesions. (A and B) A slightly elevated lesion in the middle third of the stomach is shown (arrowheads). The final histopathological diagnosis was well-differentiated adenocarcinoma, confined to the mucosa. (A) On white light imaging (WLI), the lesion appears as a whitish area with irregular margins and an irregular surface. (B) On second-generation narrow band imaging (2G-NBI), the lesion appears as a brownish area with irregular margins and an irregular surface. (C and D) A depressed lesion in the upper third of the stomach is shown (arrowheads). The final histopathological diagnosis was well-differentiated adenocarcinoma, confined to the mucosa. (C) On WLI, the lesion appears as a reddish area with irregular margins and an irregular surface. (D) On 2G-NBI, the lesion appears as a brownish area with irregular margins and an irregular surface. (E, F) A flat lesion in the upper third of the stomach is shown (arrowheads). The final histopathological diagnosis was moderately differentiated adenocarcinoma, confined to the mucosa. (E) On WLI, the lesion appears as a reddish area with irregular discoloration. (F) On 2G-NBI, the lesion appears as a brownish area with irregular discoloration.

Figure 2

Enrolment and randomisation of patients. The detection rate of early gastric cancer (the primary endpoint) and the positive predictive value for early gastric cancer (a secondary endpoint) were determined in the intent-to-treat population. Observation time (a secondary endpoint) was evaluated among all patients who underwent the examination. 2G-NBI, second-generation narrow band imaging; WLI, white light imaging.