Diagnostic accuracy of stereomicroscopy assessment of invasion depth in ex vivo specimens of early gastric cancer.

BACKGROUND

Endoscopic submucosal dissection (ESD) is an established therapeutic modality for early gastric cancer (EGC). Accurate assessment of the invasion depth is critical for evaluating treatment outcomes.

AIM: To investigate the clinical significance of stereomicroscopy in determining the invasion depth of EGC.

METHODS

This retrospective analysis included 967 patients with EGC who underwent ESD from 2014 to 2023. The mucosal and basal aspects of ESD specimens were stereomicroscopically examined. Lesions were categorized stereomicroscopically as mucosal (uniformly thick, transparent submucosal tissue) or submucosal defined by the presence of a "Basal White Sign", a localized, opaque, whitish discoloration exceeding 5 mm in diameter. Patients with uncertain classification were excluded. The accuracy of stereomicroscopic depth diagnosis and clinicopathological features of misdiagnosed cases were analyzed.

RESULTS

The overall diagnostic accuracy of stereomicroscopy for invasion depth was 74.0%. For non-ulcerated lesions, stereomicroscopy exhibited high diagnostic performance [accuracy = 93.5%, 95% confidence interval(CI): 91.1-95.4, sensitivity = 95.0%, specificity = 86.9%, positive predictive value = 96.9%, negative predictive value = 80.2%]. Conversely, performance significantly declined in ulcerated lesions (accuracy = 35.8%, 95%CI: 30.2-41.6, sensitivity = 19.1%, specificity = 95.2%, positive predictive value = 93.5%, negative predictive value = 24.8%). Tumor size of 21-30 mm (odds ratio = 1.6) and ulceration (odds ratio = 36.1) were independent risk factors for misdiagnosis. Submucosal lesions exhibited significantly larger basal vessel diameter than mucosal lesions (663.6 μm vs 505.5 μm, P < 0.001).

CONCLUSION

Stereomicroscopy is an effective diagnostic tool for determining the EGC invasion depth, particularly in non-ulcerated lesions. These findings could inform clinical practice and ESD treatment strategy optimization for EGC.