Evaluation of gastric biopsies for neoplasia - Differences between Japanese and western pathologists

Cited variations in the evaluation of gastric endoscopic biopsies for neopl asms between pathologists in Japan and those in the United States and Europ e (the West) may have stemmed from several causes. The five-tiered group cl assification of the Japanese Research Society for Gastric Cancer (JRSGC) fo r interpretation of biopsies is not used in the West. Some differences may also exist in the morphologic criteria to reach a diagnosis of dysplasia or carcinoma. The goals of this study were to test the Western and Japanese c lassifications of gastric dysplasia and adenocarcinoma and to assess the di fferences between four Japanese and seven Western pathologists. One hundred biopsies, 20 from each of the five categories of the JRSGC scheme as deter mined by one observer, were collected. The Japanese observers used the JRSG C system, expressed in Roman numerals, whereas Western pathologists used a five- or six-tiered scheme expressed in diagnostic terms. Pairwise agreemen t was evaluated using k: statistics within both groups. Consensus diagnosis on each biopsy was accepted as the opinion of the majority. The sensitivit y and specificity of each reviewer for a certain diagnosis were also assess ed. The intra,group agreements were moderate fur both the Japanese (mean k = 0.663) and the Westerners (mean k = 0.652). The pairwise agreements betwe en Japanese and Western observers were low (mean k = 0.542). Overall, the s ensitivity was low for all Japanese observers for the diagnosis of dysplasi a (38.7% vs 92.5%), and the sensitivity for the diagnosis of adenocarcinoma was high in both groups but higher among the Japanese observers (93.9% and 85.2%, respectively). Overall, the Japanese-Western interobserver agreemen t was moderate. The JRSCG scheme did not translate into higher interobserve r agreement among Japanese observers. The sensitivity for the diagnosis of gastric adenocarcinoma was high for both groups, but the specificity was lo w among the Japanese. The cause seemed to be centered around the diagnosis of dysplasia in the Western system, which was a lesion frequently interpret ed as carcinoma in Japan because of the different definitions of carcinoma in each system. Such a discrepancy might be important because it may explai n some of the differences in the prevalence and prognosis of early gastric cancer between Japan and the West. An international effort is needed to har monize morphologic criteria and analyze whether therapeutic consequences ma y stem from such discrepancies.