Cancer Gstrico

NCI Clinical Practice Guidelines in Oncology™
Gastric Cancer




























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Overview
Carcinomas originating in the upper gastrointestinal (GI) tract (esophagus, gastro esophageal junction, and stomach) constitute a major health problem around the world. It is estimated thatapproximately 36,820 new cases of upper GI carcinomas and 25,150 deaths will occur in the United States in 2007.1 There has been a dramatic shift in the location of upper GI tumors in the United tates.2 Changes in histology as well as location of upper GI tumors have also been observed in some parts of Europe.3,4 In countries n the Western Hemisphere, gastric carcinoma has migrated proximally;it occurs most frequently along the proximal lesser curvature, n the cardiac, and in the gastro esophageal junction.2 It is possible that in the coming decades these changing trends will also occur in south America and Asia.

Epidemiology of Gastric Carcinoma
Gastric carcinoma is rampant in many countries around the world. In Japan, gastric cancer remains the most common type of cancer amongmen. Its incidence, however, has been declining globally since World War II. By some estimates, it is the fourth most common malignant disorder worldwide.5, 6 Gastric carcinoma is one of the least common cancers in North America. In 2007, more than 21,260 new cases of gastric cancer are estimated to occur in the United States and 11,210 deaths are expected as a result.1 In developed countries,the incidence of gastric cancer localized to the cardiac follows the distribution of esophageal cancer; however, unlike the matter, the rates of gastric cancer have stabilized since 1998.7,8,9 Non cardiac gastric Aden carcinoma also shows marked geographic radiation; thus, countries such as Japan, Costa Rica, Peru, Brazil, China, Korea, Chile, Taiwan, and the former Soviet Union show a highincidence of the cancer.10,11 In contrast to the increasing incidence of proximal tumors in the West, non-proximal tumors continue o predominate in Japan and other parts of the world.12,13 The cause of this shift remains elusive and may be multifactorial.

Gastric carcinoma is often diagnosed at an advanced stage, because screening for gastric carcinoma is not performed in most of the world, exceptin Japan (and in a limited fashion in Korea) where early detection of gastric carcinoma is often done. Thus, gastric carcinoma continues to pose a major challenge for healthcare professionals. Risk factors include Helicobacter pylori infection, smoking, high salt intake, and other dietary factors. A few gastric cancers (1-3%) are associated with inherited gastric cancer predisposition syndromes.E-cadherin mutations occur in an estimated 25% of families with an autosomal dominant predisposition to diffuse type gastric cancers; this subset of gastric cancer has been termed hereditary diffuse gastric cancer.14 Data suggest it may be useful to provide genetic counseling and to consider prophylactic gastrectomy in young, asymptomatic carriersgerm-line truncating CDH1 mutations who belong tofamilies with highly penetrant hereditary diffuse gastric cancer.15

Staging
Two major classification systems are currently in use for gastric carcinoma. The most elaborate of these, the Japanese classification, s based on refined anatomic involvement, particularly the lymph node stations.16 The other staging system for gastric carcinoma, developed jointly by the American Joint Committee onCancer (AJCC) and the International Union against Cancer (UICC), is based on gastric cancer database and demonstrates that the prognosis of node-positive patients depends on the number of lymph nodes nvolved.17 The modern staging of gastric carcinoma is based on this tumor/node/metastasis (TNM) classification, rather than on the size of the cancer. The AJCC/UICC classification (Table 1) is...