Gastric cancer is the 4th most common cancer worldwide but only 13th in the United States (US). This rate is even higher in the Far East, particularly Japan, Korea, and China where it has been the leading cause of death. Gastric adenocarcinoma accounts for approximately 90 % of all gastric cancers. There is a slight male predominance, with diagnosis usually occurring in the sixth to seventh decade of life.

Rates of gastric cancer have significantly decreased over the past century in the United States. This is likely due to the identification and eradication of Helicobacter pylori and the introduction of refrigeration. Since the introduction of triple therapy for H. pylori infections (amoxicillin, clarithromycin, and omeprazole), the prevalence of peptic ulcer disease as well as its progression to gastric cancer has declined in developed nations. In regard to refrigeration, it is thought that the improvement in food storage has led to a decrease in salt-preservation, pickling, or smoking of meat and a decrease in bacterial contamination.

Due to the low rate in the United States, it has been found to not be cost effective to screen patients for gastric cancer. In Asian countries, where the rates of gastric cancer are much higher, screening with endoscopy has been found to be cost effective.

Due to vague and often nonspecific presenting symptoms and a low rate of screening, particularly in the United States, most patients who are diagnosed with gastric cancer are already found to be stage III or stage IV and unresectable (see section Work-Up). At time of diagnosis, 50 % have disease that extends beyond locoregional confines. Of the 50 % that have local disease, only half of those patients appear to have a resectable cancer. These findings exemplify the importance of a thorough history and physical exam with further investigation of patients that are high risk or have alarm symptoms (early satiety, weight loss, dyspepsia in those over age 45).

Weight loss and abdominal pain are the most common symptoms at the initial diagnosis. This may be accompanied by dysphagia, nausea, early satiety, and rarely a palpable mass. It is common for a patient to present to their primary care physician only complaining of dyspepsia, vague abdominal pain, and fatigue. Unfortunately, it often is not until the development of these more descriptive symptoms, known as “alarm symptoms,” that the physician further evaluates with diagnostic imaging or endoscopy. Patients with “alarm symptoms” are more likely to have gastric cancer, more likely to have advanced cancer at diagnosis, and more likely to have shorter survival.

Abdominal pain, when present, tends to be epigastric, vague, and persistent. Because of the stomach’s ability to expand, tumors need to be large before the patient experiences pain or early satiety. In patients with linitis plastica, infiltration of large areas of gastric wall will lead to poor compliance and the presence of symptoms. Dysphagia is a common symptom for tumors that involve the cardia or proximal stomach. An acute gastrointestinal bleed is uncommon (5 %), but chronic occult melena is commonly seen.

Physical exam findings are usually non-specific and often absent. If the patient does have physical findings, it is likely that they also have advanced disease. If the patient has an anterior gastric tumor, as it is grows it may become palpable in the epigastric region. Palpable left supraclavicular nodes (Virchow’s nodes) may be found in advanced stages, as well as periumbilical lymphadenopathy (Sister Mary Joseph nodes) and left axillary node (Irish’s node). If the tumor is located in the antrum or more distal towards the pylorus, it may grow into the hepaticoduodenal ligament and lead to obstructive jaundice and elevated liver function tests.

Diffuse-type gastric cancer (Table 50.2) is highly metastatic and aggressive leading to its rapid progression. This rapid progression can lead to cancer seen in the esophagus or duodenum, as well as infiltration of the entire gastric wall, known as “linitis plastica” (plastic lining) named after the stiff, undistensible gastric wall that develops after it is infiltrated with tumor.

It is important to understand the blood supply to the stomach as this is how gastric cancer spreads. The vascular supply involves four major arteries: the left and right gastric arteries on the lesser curve and the left and right gastroepiploic arteries along the greater curve. All of the vessels that supply the stomach are derived from the celiac artery. The left gastric is a direct vessel off of the celiac artery. The right gastric most commonly is a branch of the common hepatic artery. The left and right gastric arteries communicate on the lesser curvature of the stomach. The right gastroepiploic artery is a branch from the right gastric or common hepatic, and the left gastroepiploic artery is a branch of the splenic artery. These two communicate and supply blood to the greater curvature of the stomach.

Anemia is due to slow intermittent bleeding of the tumor. As the patient loses blood through the GI tract in the form of melena, there is also iron and heme loss along with RBCs. Patients often do not show signs of anemia in the acute setting because the body has not yet compensated for the losses. It is in the chronic setting that one will see chronic anemic changes.