Gastric Cancer Disease Background

Last updated: 17 October 2025
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Introduction

Gastric cancer is also called stomach cancer, or carcinoma of the stomach. This is a malignant tumor of the gastrointestinal tract that is usually aggressive and manifests in an advanced stage. The most common sites of gastric cancer are the proximal lesser curvature, cardia, and esophagogastric junction (EGJ). 

Epidemiology

Gastric cancer is the fifth most common cancer and the third most common cause of cancer-related deaths worldwide. The disease is more prevalent in males than females (two- to three-fold higher), and gastric cancer rates increase with increasing age. The incidence rates of gastric cancer are highest in Northeast Asia, South and Central America, and Eastern Europe.  

Asian regions with high gastric cancer incidence include China, Japan, the Republic of Korea, Vietnam and Mongolia, whereas lower gastric cancer incidence is seen in Hong Kong and Malaysia.  In Japan and Korea, this is the most common type of cancer in men and this may be due to genetic predisposition compounded by environmental and lifestyle factors. 

Pathophysiology

The development of the intestinal type of gastric cancer occurs after a prolonged precancerous process known as the Correa cascade. The process is initiated with a Helicobacter pylori infection causing chronic inflammation of the gastric lining that progresses to a series of precursor lesions (eg nonatrophic gastritis, atrophic gastritis, intestinal metaplasia) to gastric adenocarcinoma that occurs with sustained infection for decades. 

Risk Factors

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The risk factors in the development of gastric cancers are male gender, old age (>50 years old), Helicobacter pylori infection (usually the major cause), cigarette/tobacco use, alcohol intake, previous gastric surgery (eg partial gastrectomy), Menetrier’s disease or hypertrophic gastropathy and atrophic gastritis. Diet that has large amounts of smoked foods, salted fish, meat and pickled vegetables is also a risk factor. Nitrates and nitrites in these foods have been shown to produce bacteria that cause cancer. A low amount of fruits and vegetables in the diet, gastroesophageal reflux, stomach lymphoma, pernicious anemia, type A blood, overweight or obesity, inherited cancer syndromes (3-5%) (eg hereditary diffuse gastric cancer, hereditary non-polyposis colorectal cancer, familial adenomatous polyposis, breast cancer, Li-Fraumeni syndrome, juvenile polyposis syndrome, Peutz-Jeghers syndrome), a family history of stomach cancer (5-10%), Epstein-Barr virus (EBV), certain occupations (eg coal, metal and rubber industry workers), and common variable immune deficiency are also some of the risk factors of gastric cancer.

Classification

Most gastric cancers (over 95%) are adenocarcinomas, subdivided according to histological appearances into diffuse (undifferentiated) and intestinal (well-differentiated) types (Lauren classification).