Pathologic discordance of differentiation between endoscopic biopsy and postoperative specimen in mucosal gastric...

Tumor differentiation is a major determinant of endoscopic resection in mucosal gastric cancers, and the treatment decision is usually based on a preoperative endoscopic biopsy. However, in a proportion of patients, the pathologic assessment of differentiation differs between the endoscopic biopsy and postgastrectomy specimen. This discrepancy is important in that it may lead to an additional radical gastrectomy after endoscopic resection or unnecessary operation for patients who could have been treated with endoscopic resection. This study aimed to investigate the frequency of such cases and to identify risk factors for discordance in patients with mucosal gastric adenocarcinoma.

The clinicopathologic characteristics of 1,326 patients who underwent curative gastrectomy for mucosal gastric cancer at Asan Medical Center from 2007 to 2011 were retrospectively reviewed.

The overall discordance was 21.5 % (285 cases), and clinically significant discordant rate was 11.9 % (157 cases). Ninety-nine tumors (7.5 %) with differentiated histology on preoperative biopsy were found to be undifferentiated on postoperative pathology. Additionally, 58 patients (4.4 %) with undifferentiated histology on preoperative biopsy exhibited differentiated histology postoperatively. Multivariate analysis revealed that age, sex, tumor location, size, and gross pattern were associated with overall pathologic discordance. In patients with clinically significant discordance, only tumor location (cardia) and size ([2 cm) were independent factors for discordance.

Considering a high discordance rate of differentiation between biopsy samples and resected specimens in mucosal cancer in cardia, performing endoscopic resection for confirmative diagnosis of differentiation before total gastrectomy can be a good option.