Clinical Implications of Histologic Heterogeneity in Endoscopic Submucosal Dissection Specimens for Differentiated-Type Early Gastric Cancer.

PURPOSE: The clinical implications of histologic heterogeneity, defined as differentiated-type early gastric cancer (EGC) containing undifferentiated components, in endoscopic submucosal dissection (ESD) specimens remain unclear. We investigated the association of histologic heterogeneity and biopsy-detected poorly differentiated components with lymph node metastasis in differentiated-type EGC.

MATERIALS AND

METHODS

This retrospective study included 858 patients who underwent gastrectomy after ESD for differentiated-type EGC. Histologic heterogeneity in ESD specimens and its association with clinicopathological features, including lymph node metastasis, were analyzed. In addition, 88 pre-treatment biopsy specimens were reviewed for the presence of poorly differentiated components.

RESULTS

Histologic heterogeneity was identified in 252 (29.4%) patients, and lymph node metastasis was detected in 46 (5.4%) patients. Histologic heterogeneity was significantly associated with higher frequencies of lymphatic invasion (73.4% vs. 50.8%, P<0.001) and lymph node metastasis (8.3% vs. 4.1%, P=0.013). Among patients with available biopsy specimens, poorly differentiated components identified on biopsy were observed only in lesions with histologic heterogeneity in ESD specimens and were associated with a higher frequency of lymph node metastasis (37.5% vs. 2.5%, P=0.005).

CONCLUSIONS

Histologic heterogeneity in ESD specimens was associated with adverse pathological features, including lymphatic invasion and lymph node metastasis. These findings support the detailed documentation of histologic heterogeneity in ESD pathology reports and minor poorly differentiated components in biopsy specimens to assist in risk stratification and individualized treatment planning for differentiated-type EGC.