Problems arising from Eastern and Western classification systems for gastrointestinal dysplasia and carcinoma: are they resolvable?

Abstract

It has become increasingly apparent that the Japanese and Western systems of classifying dysplasia and carcinoma in the gastrointestinal tract are not the same. The implication of these differences is that in an article in a Western journal on gastrointestinal 'cancer' originating from Japan, it is often impossible to repeat the study to confirm or refute it, because of these differences in definitions. Although there is no reason why it should not be just as much of a problem if Western research is published in Japanese journals, this is currently not a major problem. The terminological differences do not mean that one is right and one wrong; they are simply different. We had an opportunity to look at these differences in detail in a series of 100 gastric biopsies. In this review, we outline these differences and indicate the similarities, differences and problems between these two systems. 'Carcinoma' is diagnosed in Japan by virtue of its structural and cytological features, but by invasion in the Western system. Adenoma does not mean a dysplastic lesion in the Japanese system (although it can) but in most cases is similar to low-grade dysplasia irrespective of the macroscopic/endoscopic appearances (hence flat and depressed adenomas in the Japanese system); however, most examples of high-grade dysplasia in the Western system, as well as some low-grade dysplasia, becomes 'cancer' in the Japanese system. Conversely, both have conceptual areas that are useful in the other's systems. Because we were ultimately able to use each other's systems, we were able to show where these systems come together and diverge. These provide hope that a common classification encompassing both systems that allows communication between both systems is feasible.

Early gastric cancer: diagnosis, staging, and clinical impact. Evaluation of 530 patients. New elements for an updated definition and classification

“…Endoscopic resection of early gastric cancers with no risk of lymph node metastases is a standard technique in Japan, probably because of the high incidence of gastric cancer and the fact that more than half of Japanese gastric neoplasms are diagnosed at an early stage. This finding is also the result of the existence of different classification systems for gastrointestinal dysplasia and gastric carcinoma in Western and Eastern countries [10][11][12][13][14][15][16]. Recently endoscopic mucosal resection (EMR) has been increasingly accepted and regularly used in Western countries.…”

“…This percentage of ''early lesions'' is considered to be really good for Western countries, even though not yet comparable to those of Eastern countries, where EGCs represent more than 50 % of all tumors [8]. The presence of an active mass screening program [9] and different classification systems for gastrointestinal dysplasia and gastric carcinoma in Eastern and Western countries [10][11][12][13][14][15][16] still accounts for significant differences in the detection of EGC.…”

Molecular and Cellular Phenotypic Profiles of Gastric Noninvasive Neoplasia

“…For instance, there is disagreement between Western and Japanese pathologists (Riddell and Iwafuchi, 1998;Schlemper et al, 1997Schlemper et al, , 2000, and even between Japanese pathologists (Tamura et al, 1996a), as to the definition of dysplasia (or adenoma) versus (well-differentiated tubular) adenocarcinoma. Carcinoma is diagnosed by virtue of the tumor's structural and cytologic features in Japan but by evidence of invasion in the Western hemisphere (Riddell and Iwafuchi, 1998;Schlemper et al, 1997). It is likely that because of these differences in histopathologic criteria, the results of molecular analyses of gastric neoplasia have also shown considerable disparity.…”

“…The therapeutic decision depends on several clinicopathologic factors, including macroscopic appearance, tumor size, and histopathologic diagnosis. Although an accurate histopathologic diagnosis is essential, discrepancies have been recognized in the diagnosis of carcinoma versus dysplasia (or adenoma) between pathologists and, in particular, between Western and Japanese pathologists (Riddell and Iwafuchi, 1998;Schlemper et al, 1997Schlemper et al, , 2000. Although objective diagnostic markers are desirable, the results of genetic analyses of gastric noninvasive neoplasia also seem to be inconsistent among pathologists.…”

The role of growth patterns, according to Kodama's classification, and lymph node status, as important prognostic factors in early gastric cancer: analysis of 412 cases

“…This large number of EGCs is due both to the presence of an active mass screening program which was introduced a number of years ago [17], and to the existence of different classification systems for gastrointestinal dysplasia and gastric carcinoma in Western and Eastern countries [18][19][20][21][22][23].…”