Journal of Cancer Prevention 2015; 20(1): 25-40
Published online March 30, 2015
https://doi.org/10.15430/JCP.2015.20.1.25
© Korean Society of Cancer Prevention
Yo Han Park1, and Nayoung Kim1,2
1Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, 2Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea
Correspondence to :
Nayoung Kim, Department of Internal Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173 beon-gil, Bundang-gu, Seongnam 463-707, Korea Tel: +82-31-787-7008, Fax: +82-31-787-4051, E-mail: nayoungkim49@empas.com, ORCID: Nayoung Kim, http://orcid.org/0000-0002-9397-0406
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Atrophic gastritis (AG) and intestinal metaplasia (IM) are the main precursor lesions of gastric cancer as the incidence of gastric cancer increases in the gastric mucosa involved with AG and IM. The prevalence of AG and IM vary depending on countries, even it represents diverse results in the same nation. Usually AG is antecedent of IM but the etiologies of AG and IM are not always the same. The sensitivity and specificity of diagnostic methods to detect AG and IM are different. Furthermore, the management strategy of AG and IM has not been established, yet.
Keywords: Atrophic gastritis,
Gastric cancer remains the second most frequent cause of cancer-related deaths and ranks 4th in cancer incidence worldwide.1 In Republic of Korea, gastric cancer is the second most common cancer followed by thyroid cancer and the third cause of cancer-related death followed by lung and liver cancer in the database of 2013.2 The prognosis of gastric cancer varies depending on stages. The 5-year survival rates for advanced gastric cancer are less than 20%. On the contrary, early gastric cancer (EGC) makes a good prognosis that the 5-year survival rates are over 90% to 95%.3-5 Therefore, it is important to individualize the management for high risk group of gastric cancer. The risk factors of gastric cancer are
Chronic inflammation can damage inflamed cells and trigger a multistep process of carcinogenesis. In premalignant tissues associated with chronic inflammation, tumor cells and leukocytes of various kinds such as neutrophils, macrophages, monocytes, mast cells, eosinophils, dendritic cells, and lymphocytes are present.12,13 These inflammatory cells contribute to cancer initiation, promotion and metastasis by producing cytokines, reactive oxygen species, and reactive nitrogen species. Various oxidant products can damage cellular DNA, RNA, and proteins by chemical reactions such as oxidation, nitration, nitrosation, and halogenation. Damages of cellular components result in increased mutations and altered functions of important enzymes and proteins in premalignant tissues, so contributing to the multistage carcinogenesis process.14 According to the Correa model, chronic inflammation of gastric mucosa triggers a pathway of chronic active gastritis, multifocal atrophy, IM, gastric dysplasia and finally invasive gastric adenocarcinoma (Fig. 1).15 The pathogenesis of intestinal type gastric cancer can be explained by a multistep process from chronic gastritis through AG, IM, and dysplasia to cancer. The presence of AG, which has been traditionally defined as the loss of glands,16 is well known as a risk factor of gastric cancer. The risk of gastric cancer increases with greater extent and higher degree of gastric mucosal atrophy.17 Gastric IM is defined as the replacement of the surface, foveolar, and glandular epithelium in the gastric mucosa by intestinal epithelium with the presence of Paneth cells, goblet cells and absorptive cells.17 Several studies suggest that AG and IM are major precursor lesions of gastric cancer.18-20 These relationships were observed before the identification of
A meta-analysis of 14 studies on incidence of AG was reported in 2010,10 of which the incidence rates of AG ranged from 0% to 10.9% per year.10 This wide range of incidence is explained by the particular settings in which the diagnosis of AG was made.10 The lowest incidence rates (0%) were found in patients with reflux esophagitis and in patients successfully treated for
Several studies have investigated that dietary causes such as excessive salt intake, deficient ascorbic acid, and insufficient carotene could be risk factors of AG, IM, and gastric cancer.15,51 However, among the many risk factors,
In a multicenter prospective study in Republic of Korea, risk factors of AG were
Many studies show that the
There is no universally accepted classification of gastritis, although several classifications of gastritis have been proposed. The first classification based on histopathological examination of gastric mucosa collected by so-called blind biopsies and samples collected during surgical procedures was created by Schindler.61 Schindler61 described that gastritis was divided into a superficial gastritis (Fig. 2B) that may progress to AG (Fig. 2C) and IM (Fig. 2D) with time, which is different from normal (Fig. 2A). Additionally, Schindler61 proposed that there were different courses and prognoses of disease by the type of the gastritis. And a novel classification and grading of gastritis was devised by a group of experts at the 9th World Congress of Gastroenterology in Sydney, Australia in 1990.62 The histological division of Sydney System is a practical guideline upon which the morphological features of gastritis in endoscopic biopsy samples should be documented. Type, severity and extent of gastric inflammation composed to possible etiology should be detailed depending on the chart. The Sydney System asserted the routine gastric biopsy sampling protocol (two from antrum and two from corpus, both from anterior and posterior walls) and sample fixation in adequately labelled separate containers.62 Now the updated Sydney system in 1996 is most widely used as the classification of gastritis.63 The original Sydney classification of gastritis dividing into gastritis acute, chronic and special forms, and grading of chronic inflammation, neutrophil activity, atrophy, IM and
The updated Sydney system is the most widely used classification of gastritis. However, it does not reflect prognosis of gastric cancer risk in subjects with CAG. Therefore, the Operative Link on Gastritis Assessment (OLGA) was developed to improve the histological staging system for gastric atrophy.64 OLGA system uses gastric biopsy sampling protocol defined by Sydney System and the histological grading system recommended by the updated Sydney System (Fig. 5).64 Long-term follow-up studies with follow-up ranges from 144 to 204 months proved that the OLGA staging reflects relevant information on clinic-pathological outcome of gastritis and therefore
IM could be classified according to the phenotype of mucin. Type I IM expresses only sialomucins, type III expresses sulfomucins and type II expresses a mixture of gastric and intestinal mucins.66 Several studies reported that type III or incomplete IM increase the risk of gastric cancer.67,68 However, a contrary result has been published.69 Furthermore, IM subtyping was not found to play a major role in the prediction of gastric cancer development in Republic of Korea.70 At the present time subtyping of IM is not recommended for clinical practice.71 However, a recent systemic review concluded that the incomplete IM was significantly related to the prevalence of gastric cancer. Moreover, it reported that the relative risks of gastric cancer were from 4- to 11-fold higher for the presence of incomplete type in comparison to complete type or in comparison to the absence of incomplete type. This systemic report concluded that subtyping of IM have the scientific evidence on the evaluation of gastric cancer risk.72
In most of previous studies about the clinical relevance of endoscopic and histologic diagnosis of the gastritis, the diagnosis of gastritis should have been based on histological examination of the gastric mucosa.73,74 Especially in the young age group, a high index of suspicion of gastric atrophy is important, and confirmation of the diagnosis by histology is necessary.75 However in another study, endoscopic and histological diagnosis displayed high correlation.76 Particularly, the benefits of upper endoscopy to conform atrophic change of gastric mucosa are generally acceptied.77,78 Endoscopic features of AG is the visibility of a vascular pattern of gastric mucosa (Fig. 2C) than normal gastric mucosa (Fig. 2A). Gastric IM (Fig. 2D) is defined as the replacement of the surface, foveolar, and glandular epithelium in the oxyntic or antral mucosa by intestinal epithelium. The endoscopic finding of IM is observed as a mucosal nodular pattern, usually occuring after the occurrence of the AG. It is not difficult to diagnose severe cases of AG and IM properly by endoscopic findings, but it is difficult to make the diagnoses of mild AG and IM.75 Sometimes endoscopic diagnosis is not correlated to histological diagnosis. Therefore, it is proper to biopsy in suspected cases of AG and IM. However, atrophic mucosal changes are not distributed similarly in whole gastric mucosa. So multiple endoscopic biopsy of gastric mucosa does not always represent AG. Furthermore, it is difficult to take multiple biopsies of all subjects with simple gastritis.79,80 To resolve this clinical difficulty, noninvasive tests for precursor lesions such as serum level of pepsinogen (PG), gastrin-17 and
Endoscopic diagnosis of AG and IM is the basic method. However, there is the possibility of low sensitivity, specificity and inter-observer variation. Endoscopic diagnosis of AG is made when the visibility of a vascular pattern followed by loss of gastric mucosal gland is present (Fig. 2C). There are various criteria to endoscopic classification of atrophic gastritis. AG due to
Other methods for endoscopic diagnosis of AG or IM are magnification chromoendoscopy and narrow band imaging (NBI). Several studies have suggested that chromoendoscopy with magnification could help to identify lesions of IM and dysplasia.85 However, high resolution magnifying endoscopy without chromoendoscopy also appears superior to standard endoscopy, allowing great accuracy for the diagnosis of
The second method of diagnosis of AG is histopathology. The updated Sydney system is the most widely accepted for classification and grading of gastritis. The updated Sydney system recommended five biopsies, two from the antrum, one from the incisura, and two from the corpus, because atrophic mucosal change and IM of gastric mucosa progress from antrum to body (Fig. 3).63 If it is difficult to obtain at these three points, biopsies from antrum and corpus are recommended. It is desirable to examine specimens from antrum and corpus of lesser and greater curvature, yet there are practical difficulties. Clinically, one biopsy specimen from lesser curvature and the other from greater curvature are used to evaluate AG and IM.73,84,90
Histological diagnosis is difficult when the specimens are inadequate. Deep portion of normal gastric mucosa are composed of different types of cells in antrum and body. Normal gastric mucosa of the antrum is composed of mucous glands which secrete gastric mucus, and that of the body is composed of parietal cell and chief cell which secrete gastric acid and digestive enzymes. Sometimes severe inflammation obscures the gland’s population, making it impossible to assess mucosal atrophy reliably. Such cases can be labeled as ‘indefinite for atrophy’ and the final judgment can be deferred until the inflammation has regressed. In addition, the diagnosis of ‘indefinite for atrophy’ may be controversial among pathologists due to the difficulty in histological diagnosis.91 IM is defined as the replacement of the surface, foveolar, and glandular epithelium in the oxyntic or antral mucosa by intestinal epithelium. These IM has been subtyped by classification of mucin expression. There are several classification systems for IM. The most widely used and useful classification is was made by Jass and Filipe92 in 1981. Type I IM (complete) is positive for the sialomucin, and type II IM (incomplete) is positive for sialomucin in goblet and columnar cell. While, type III IM (imcomplete) is positive for sulphomucin.92 Complete type IM is similar to small intestine in pathologic features and tests positive for the MUC2 secreted by goblet cells. While, incomplete type IM is similar to large intestine in pathologic features, and positive for MUC5AC, MUC6 secreted by gastric mucosa and MUC2.70,93 In addition, high iron diaminealcian blue (HID-AB) stain can help classify the types of IM. Type I IM expresses only sialomucins (bright blue) (Fig. 7; type I) and type II, III expresses sialomucins (bright blue) and sulfomucins (black) (Fig. 7; type II and type III).70 Jass and Filipe92 reported that type III IM is associated with intestinal type gastric cancer. Other researchers have suggested that incomplete type IM is associated with gastric cancer. As such, it is still controversial discussing which type of IM is related with gastric carcinogenesis.67,68,70 In a cohort study of 861 subjects conducted in Republic of Korea, type III IM was associated with aging (
The third diagnostic method of AG or IM is a measurement of serum PG I, II and I/II ratio. The radioimmunoassay method is used to measure serum PG levels. Recently, a new method has emerged to measure PG level.94,95 The present methods to measure PG level are Latex-enhanced Turbidimetric Immunoassay (HBi Corp., Seoul, Korea; imported from Shima Laboratories, Tokyo, Japan),90,94,95 and enzyme-linked immunosorbent assays (Biohit ELISA kit; Biohit, Helsinki, Finland).96,97 PG has been used to screen AG, IM and gastric adenocarcinoma for more than 20 years because of its non-invasiveness and cost-effectiveness. In Japan, PG screening for gastric cancer has been used to improve population compliance.98 However, PG screening is not accepted as a generalized screening method of AG or IM worldwide because of low positive predictive value in other countries.99
PG I is produced by chief cells in antrum and corpus, while PG II is produced by the chief cells and mucous neck cells of the whole gastric mucosa. When gastric atrophy develops, chief cells are replaced by pyloric glands, leading to a decrease in PG I level, while PG II levels is relatively unaffected, so a low PG I/II ratio reflect the severity of AG.100,101 In a prospective study of 5,113 subjects in Japan, screening for gastric cancer with PG I < 70 ng/mL and PG I/II ratio < 3 as the cut-off points had the sensitivity and specificity of 84.6% and 73.5%, respectively.102 Generally PG I/II ratio 3.0 or less has been widely accepted as a cut-off value in several studies.103 However, in a recent Korean study which evaluated the relationship between PG level and AG, a new cut-off value of PG I/II ratio, 3.2, was suggested to diagnose AG.90 The study suggested that serum PG I/II ratio remarkably decreased in correlation with the extent of atrophy by the Kimura-Takemoto classification.90 In another Korean research, PG I and PG II were negatively correlated with AG and only PG I/II ratio was positively correlated with AG.95 Serum PG I and PG II were higher in
Moreover, a significantly positive correlation was found between age and the PG II (
Up to the present time, there are no unified clinical guidelines for prevention of gastric cancer regarding the classification of high-risk groups progressing to gastric cancer.104 However, through many studies, AG and IM are considered as precancerous lesions. Prevention and treatment of AG and IG could decrease the prevalence of gastric cancer. AG and IM could be managed by several strategies.
The 5-year survival rate of EGC was greater than 90%.125 Moreover, surgery is no longer needed because of the recent advances in endoscopic resection techniques and technologies for EGC.126 Therefore, it is important to establish optimal screening methods in high gastric cancer prevalence area such as Republic of Korea and Japan. Republic of Korea and Japan have been conducting biennial screening of gastric cancer in general population over 40-years-of-age.127,128 However, optimal screening interval of gastric cancer is still under discussion. In a Japanese study, the 5-year survival rate was significantly higher in subjects who had undergone endoscopic examinations within 2 years before being diagnosed with gastric cancer than that of patients who had not (96.5% vs. 71.0%;
Adequate consumption of vegetables and fruits seems to reduce the risk of cancer and decrease the incidence of gastric cancer in the West. Although some studies for premalignant gastric lesions have shown positive results of vitamin C, folic acid, and beta-carotene supplementation, though these results were not confirmed in a large meta-analysis.132-135
Gastric cancer is still a major cause of death in Republic of Korea. To reduce the prevalence of gastric cancer, it is very important to classify and manage the high risk groups of gastric cancer. Furthermore,
The prevalence of AG and IM in the world.
Author (year) | Country | Diagnostic methods | Study population (n) | AG (%) antrum/body | IM (%) antrum/body |
---|---|---|---|---|---|
Kim et al. (2008)11 | Korea | Histology | 389 | 42.5/20.1 | 28.6/21.2 |
Kim et al. (2008)42 | Korea | Histology | 713 | 42.7/38.1 | 42.5/32.7 |
Park et al. (2012)43 | Korea | Endoscopy | 25,536 | 27.1b | 7.1b |
Joo et al. (2013)44 | Korea | Endoscopy | 4,023 | 40.7b | 12.5b |
Weck et al. (2007)45 | Germany | Serologya | 9,444 | 6.0b | - |
Borch et al. (2000)46 | Sweden | Histology | 501 | 9.4b | - |
Asaka et al. (2001)47 | Japan | Histology | 2,455 | 55.5b | 24.2b |
Zou et al. (2011)48 | China | Histology | 1,022 | 63.8b | - |
Eriksson et al. (2008)49 | Finland | Histology | 505 | - | 18.8/7.1 |
Almouradi et al. (2013)50 | USA | Histology | 437 | - | 15.0b |
AG, atrophic gastritis; IM, intestinal metaplasia..
bPrevalence of AG or IM in the antrum and/or body.
Histological parameters of AG and IM after
Author (year) | Country | Study arms (n) | Follow-up (mo) | Histologic parameters | ||||
---|---|---|---|---|---|---|---|---|
Eradicated | Not eradicated | AG | IM | |||||
antrum | corpus | antrum | corpus | |||||
Sung et al. (2000)105 | China | 226 | 245 | 12 | Yes | Yes | Yes | Yes |
Kim et al. (2000)106 | Korea | 41 | 16 | 24 | No | No | Yes | Yes |
Annibale et al. (2000)107 | Italy | 5 | 7 | 6 | Yes | Yes | Yes | Yes |
Ohkusa et al. (2001)108 | Japan | 115 | 48 | 12-15 | Yes | Yes | Yes | Yes |
Ruiz et al. (2001)109 | Colombia | 29 | 21 | 72 | Yes | No | No | No |
Ito et al. (2002)110 | Japan | 22 | 22 | 60 | Yes | Yes | Yes | Yes |
Annibale et al. (2002)111 | Italy | 40 | 0 | 6-12 | Yes | Yes | Yes | Yes |
Yamada et al. (2003)112 | Japan | 87 | 29 | 10-50 | Yes | Yes | Yes | Yes |
Iacopini at al. (2003)113 | Italy | 10 | 0 | 12 | Yes | No | Yes | No |
Kamada et al. (2003)114 | Japan | 37 | 8 | 36 | Yes | No | No | No |
Wambura et al. (2004)115 | Japan | 107 | 118 | 12 | Yes | Yes | Yes | Yes |
Lahner et al. (2005)116 | Italy | 38 | 36 | 48-137 | Yes | Yes | Yes | Yes |
Lu et al. (2005)117 | China | 92 | 87 | 36 | Yes | Yes | Yes | Yes |
Kamada et al. (2005)118 | Japan | 1,787 | 233 | 12 | Yes | Yes | Yes | Yes |
Toyokawa et al. (2010)119 | Japan | 241 | 19 | 60 | Yes | Yes | Yes | Yes |
AG, atrophic gastritis; IM, intestinal metaplasia..
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