Integrated diagnostic strategy for the invasion depth of early gastric cancer by conventional endoscopy and EUS.

Background: Although conventional endoscopy (CE) and EUS are considered useful for predicting the invasion depth (T-staging) in early gastric cancer (EGC), no effective diagnostic strategy has been established.

Objective: To produce simple CE criteria and to elucidate an efficient diagnostic method by combining CE and EUS for accurate T-staging.

Design: Single-center retrospective analysis.

Setting: Academic university hospital.

Patients: Consecutive patients with EGC from April 2007 to March 2012 who underwent CE and EUS before treatment.

Interventions: Recorded endoscopic images were independently reviewed by 3 observers. The CE criteria for massive invasion were defined, and their utility and the additional value of EUS were assessed.

Main Outcome Measurements: The accuracy of CE based on the criteria and the accuracy of EUS.

Results: Two hundred thirty patients were enrolled: 195 with mucosal cancer or cancer in the submucosa less than 500 μm from the muscularis mucosae and 35 with invasive cancers. Multivariate analysis of the CE findings by 1 observer revealed that an irregular surface and a submucosal tumor-like marginal elevation were significantly associated with massive invasion. The simple CE criteria, consisting of those 2 features, had an overall accuracy of 73% to 82% and no significant differences in the diagnostic yield compared with EUS in all observers. CE accurately revealed mucosal cancer, and EUS efficiently salvaged the lesions that were over-diagnosed by CE. With our strategy, which involved the CE criteria and the optimal use of EUS, the comprehensive accuracy exceeded 85% in each observer.

Limitations: Retrospective, single-center study.

Conclusions: We demonstrated a practical strategy for T-staging in EGC using simple CE criteria and EUS.