Society: ASGE

[Introduction] Early detection of gastric cancer offers favorable treatment outcomes. Second-generation narrow-band imaging (NBI) is expected to improve the detection of early gastric cancer (EGC); however, the detection rate is not superior to that of white light imaging (WLI). The latest endoscopic system EVIS X1 (Olympus, Tokyo, Japan) includes a higher-definition WLI, third generation (3G)-NBI, and texture and color enhancement imaging (TXI). We conducted a randomized phase II trial to compare the ability of 3G-NBI, TXI, and WLI to detect gastric neoplasms (GN) (jRCT1032210213).
[Methods] The eligibility criteria included patients aged 20–85 years with either of the following: 1) scheduled surveillance endoscopy after endoscopic resection for GN, or endoscopic resection, chemotherapy, or radiotherapy for esophageal cancer, or 2) scheduled preoperative endoscopy for known GN or esophageal cancer. Written informed consent was obtained from all participants. The EVIS X1 system and a high-definition gastroscope with an optical zoom (GIF-XZ1200) were used. Patients were randomly assigned in a 1:1:1 ratio to the 3G-NBI (primary 3G-NBI and secondary WLI), TXI (primary TXI and secondary WLI), and WLI (primary and secondary WLI) arms, with the WLI arm set as the reference arm. Non-magnifying primary observation was performed to detect the GN lesions. After completing the primary observation of the entire stomach, a secondary WLI was immediately performed by the same endoscopist. All suspected GN lesions were biopsied at the end of the examination. Pathological diagnoses were made based on biopsied tissue or specimens obtained from endoscopic or surgical resection by expert pathologists at each institution. The primary endpoint was GN detection rate in the primary observation, including cancer and adenoma. The other endpoints were the miss rate for GN, EGC detection rate, and positive predictive value (PPV) for the diagnosis of GN in the primary observation. We assumed that the primary endpoint would be 3.0% for one image-enhanced endoscopy (IEE) and > 4.3% for the other. The sample size was set to 300 per arm to ensure that 80% or more of the participants correctly selected the most promising IEE.
[Results] 901 patients were enrolled from six institutions and assigned to the 3G-NBI, TXI, and WLI arms (300/300/301). Of these, 222 (24.6%) underwent preoperative examination. The GN detection rate in the 3G-NBI, TXI, and WLI arms were 7.3%, 5.0%, and 5.6%, respectively, with the 3G-NBI showing the highest detection rate. In addition, the miss rates for GN were 1.0%, 0.7%, and 1.0%, the EGC detection rates were 5.7%, 4.0%, and 5.6%, and the PPVs for the diagnosis of GN were 36.5%, 21.3%, and 36.8% in the 3G-NBI, TXI, and WLI arms, respectively.
[Conclusion] 3G-NBI is the most promising modality for the detection of GN when compared with TXI and WLI.

Masashi Tamaoki

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