The Macroscopic Classification of Early Neoplasia of the Digestive Tract

Objectives

In 1962, in Japan, a macroscopic classification of early gastric carcinoma was established to facilitate discussions between endoscopists, radiologists, surgeons, cytologists and pathologists [1]. The classification into types I, IIa, IIb, IIc, and III has also been applied to superficial esophageal carcinoma since 1972 and to early colorectal neoplasia since 1977 [2] [3]. This classification, based on the extent of elevation and depression, was originally meant to be used only for carcinomas that are limited to the mucosa and submucosa, and it was intended that lesions should be classified on the basis of inspection of surgically resected specimens with the naked eye. It was advocated that the prefix “type 0” (0-I, 0-IIa, etc.) be used to distinguish these early and superficial carcinomas from advanced carcinomas. The latter were classified into type 1 (protuberant), type 2 (ulcerated with clear margin), type 3 (ulcerated with infiltration), type 4 (diffusely infiltrating), and type 5 (unclassifiable). Moreover, it was advocated that the word "like" be appended for lesions clinically suspected to be advanced (IIc-like, IIa-like, etc.), and the word “like” should be omitted only after histological confirmation that the lesion was a carcinoma limited to the mucosa and submucosa (T1 tumor). For the colorectum it has been proposed to append “like” to all lesions for as long as histological confirmation is lacking [3].

However, in recent years it has become the general practice to apply the classification to the endoscopic gross appearance of any tumor resembling early carcinoma, including adenoma/dysplasia and advanced carcinoma, and to omit using the prefix “0”, or the suffix “like”.

The macroscopic classification depicted in Figure [1] is clinically useful and simple. That is why it has continued to be widely used in Japan for 40 years and is becoming increasingly popular in Western countries. The various macroscopic types are observed with different frequencies in each part of the digestive tract (Table [1]). As the various types reflect differences in expected depth of invasion (Table [2]) [4 - 6), the classification is helpful when one has to decide between endoscopic treatment and surgical resection. For example, endoscopic mucosal resection is clearly not indicated for type I or type III esophageal lesions (Table [2]) [6] [7].

Figure 1 Macroscopic classification of early neoplastic lesions of the digestive tract

Table 1 Relative frequency of macroscopic types of early neoplasia as described in the Japanese literature 4 5 6 Macroscopic type Gastric early carcinoma 4, % (n = 17 048) Colorectal adenoma and early carcinoma 5, % (n = 9533) Esophageal superficial squamous cell carcinoma 6, % (n = 259) I* 7 57 16 IIa 9 39 4 IIb 2 NC 20 IIc† 70 2 45 IIa+IIc 7 2 8 III‡ 3 0 7 Total 98 100 100 NC, not calculated, because for colorectal neoplasia the small number of type IIb lesions was included in the group of type IIa lesions. * Including I + IIc, † including IIc + IIa and IIc + III, ‡ including III + IIc and III + IIb.

Table 2 Rate of submucosal invasion according to macroscopic type of early neoplasia as described in the Japanese literature 4 5 6 Macroscopic type Gastric early carcinoma 4, % (n = 17 048) Colorectal adenoma and early carcinoma 5, % (n = 9533) Esophageal superficial squamous cell carcinoma 6, % (n = 259) I* 49 2 98 IIa 32 1 0 IIb 13 NC 0 IIc† 49 16 34 IIa + IIc 69 16 20 III‡ 51 NC 100 NC, not calculated, because for colorectal neoplasia the small number of type IIb lesions was included in the group of type IIa lesions, and no type III lesions were discovered. * Including I + IIc, † including IIc + IIa and IIc + III, ‡ including III + IIc and III + IIb.

References

• 1 Japanese Research Society for Gastric Cancer .Japanese classification of gastric carcinoma. Tokyo; Kanehara 1995 1st English ed.
• 2 Japanese Society for Esophageal Diseases .Guidelines for the clinical and pathologic studies on carcinoma of the esophagus (in Japanese with English diagnostic terms). Tokyo; Kanehara 1999 9th ed.
• 3 Japanese Society for Cancer of the Colon and Rectum .Japanese classification of colorectal carcinoma. Tokyo; Kanehara 1997 1st English ed.
• 4 Fukutomi H, Sakita T. Analysis of early gastric cancer cases collected from major hospitals and institutes in Japan.  Jpn J Clin Oncol. 1984;  14 169-179
• 5 Kudo S. Early colorectal cancer: detection of depressed types of colorectal carcinoma. Tokyo; Igaku-Shoin 1996 1st ed: 81-93
• 6 Makuuchi H, Shimoda H, Mizutani K. et al . Endoscopic criteria for invasive depth of superficial esophageal cancer.  Dig Endosc. 1997;  9 110-115
• 7 Schlemper R J, Kato Y, Stolte M. Review of classifications of gastrointestinal epithelial neoplasia: differences in diagnosis of early carcinomas between Japanese and Western pathologists.  J Gastroenterol. 2001;  36 445-456
• 8 Hirata I, Tanaka M, Sugimoto K. et al . Clinicopathological study on flat and depressed minute colorectal carcinomas.  Dig Endosc. 1991;  3 526-535
• 9 Saitoh Y, Obara T, Watari J. et al . Invasion depth diagnosis of depressed type early colorectal cancers by combined use of videoendoscopy and chromoendoscopy.  Gastrointest Endosc. 1998;  48 362-370
• 10 Sano T, Okuyama Y, Kobori O. et al . Early gastric cancer: endoscopic diagnosis of depth of invasion.  Dig Dis Sci. 1990;  35 1340-1344
• 11 Kudo S, Kashida H, Tamura T. et al . Colonoscopic diagnosis and management of nonpolypoid early colorectal cancer.  World J Surg. 2000;  24 1081-1090
• 12 Fujii T, Rembacken B J, Dixon M F. et al . Flat adenomas in the United Kingdom: are treatable cancers being missed?.  Endoscopy. 1998;  30 437-443
• 13 Rembacken B J, Fujii T, Caims A. et al . Flat and depressed colonic neoplasms: a prospective study of 1000 colonoscopies in the UK.  Lancet. 2000;  355 1211-1214
• 14 Schlemper R J. Differences in the diagnostic criteria used by Japanese and Western pathologists to diagnose colorectal carcinoma: response.  Gastrointest Endosc. 1999;  50 447-448