Diagnosis
Pertinent positives and negatives
Peptic ulcer disease (PUD)
Burning abdominal pain, nausea, vomiting, bloating. History of using a PPI or H2 blocker. Pain presents post-prandially and usually resolves on its own. Not likely to have significant weight loss. History of H. pylori and/or chronic NSAID use
Gastroesophageal reflux disease (GERD)
Post-prandial abdominal and chest pain (heartburn). Bitter taste in one’s mouth. Regurgitation, bloating
Pancreatitis
Mid-epigastric pain. Significantly tender to palpation. Elevated pancreatic enzymes. Often a history of alcohol abuse or cholelithiasis
Cholelithiasis
Right upper quadrant or mid-epigastric pain, often post-prandial and intermittent (colicky). Elevated liver function tests (LFTs). Ultrasound positive for stones
Hiatal hernia
Sliding and paraesophageal hernias may cause upper abdominal pain and chest pain with or without GERD symptoms. May need immediate surgical intervention if signs of incarceration or strangulation (pain with nausea/vomiting)
Gastric outlet obstruction
Persistent nausea/vomiting and abdominal discomfort and bloating, possibly early satiety
Small bowel obstruction
Nausea/vomiting with vague abdominal pain. Patients will usually have a history of abdominal surgery, most common cause of an obstruction is adhesions
Gastric cancer
Vague abdominal pain, involuntary weight loss, early satiety, dysphagia, iron deficiency anemia, cachexia
What Is the Most Likely Diagnosis?
In all elderly patients that have significant weight loss and a positive fecal occult blood test, the diagnosis is cancer until proven otherwise. Gastric cancer is rare in the United States, but is one of the most common cancers worldwide and is particularly common in Asians. In the United States, colon cancer would be higher on the list. However, due to the location of the pain, the weight loss, and the Korean decent, gastric cancer is most likely.
Watch Out
It is important to consider gastric cancer as part of your differential in any patient that presents with upper abdominal pain and significant weight loss as early diagnosis is critical to improved long-term survival. In the United States, approximately 50 % of gastric cancers have already spread past the confines of surgical resectability at the time of diagnosis, resulting in a high mortality rate.
Epidemiology
What Is the Prevalence of Gastric Cancer and What Causes It?
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.
Table 50.1
Risk factors for the development of gastric cancer
Positive family history |
Diet (high in nitrates, salt, fat) |
Familial polyposis |
Gastric adenomas |
Hereditary nonpolyposis colorectal cancer |
Helicobacter pylori infection, causing: Atrophic gastritis, intestinal metaplasia, dysplasia |
Previous gastrectomy or gastrojejunostomy (>10 y ago) |
Tobacco use |
Ménétrier’s disease |
Type A blood |
BRCA 1 and BRCA 2 |
HER2 gene overexpression |
Peutz-Jegher’s syndrome |
Watch Out
Risk factors for the development of gastric cancer are multifactorial. It has been recognized that there is a synergism between H. pylori infections and other factors leading to a higher rate of gastric dysplasia and metaplasia.
Screening
Is It Worth Screening Patients for Gastric Cancer?
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.
Why Is the Mortality Rate So High for Gastric Cancer?
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).
History and Physical
What Are the Most Common Symptoms for a Patient with Gastric Cancer?
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.
Are There Specific Findings on Physical Exam?
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.
Pathophysiology
What Are the Two Histologic Types of Gastric Adenocarcinoma?
Intestinal-Type Gastric Adenocarcinoma
This well-differentiated cell type arises from the gastric mucosa and is usually located in the distal stomach. This histologic type is more commonly seen in the sporadic patient that has high exposure to a poor diet, smoking, alcohol, and other environmental risk factors. This is also the type that has decreased with the eradication of H. pylori and other detrimental risk factors. Intestinal type accounts for 53 % of all gastric adenocarcinomas. Intestinal type has a stepwise pattern of progression leading to gastric adenocarcinoma. Patients will start with an H. pylori-induced inflammatory reaction (acute gastritis) which leads to chronic atrophic gastritis, intestinal metaplasia, dysplasia, and finally carcinoma.
Diffuse-Type Gastric Adenocarcinoma
This is a poorly differentiated tumor that is believed to originate from the lamina propria of the stomach and grows in an infiltrative, submucosal pattern. Unlike the intestinal type, the unorganized growing pattern leads to gastric thickening without a discrete mass. Diffuse-type gastric adenocarcinomas are most often found in the proximal stomach near the cardia. Because this type is related to congenital disorders, it is also most often found in younger patients compared to the intestinal type. These patients do not follow the typical histologic progression, instead jumping directly from chronic atrophic gastritis to adenocarcinoma.
What Is Linitis Plastica?
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.
Table 50.2
Types of gastric adenocarcinoma
Intestinal | Diffuse |
---|---|
Well differentiated | Poorly or undifferentiated |
Distal stomach | Anywhere, but most often proximal stomach |
Secondary to environmental factors | Secondary to congenital disorders |
Decreasing in incidence | No change in incidence |
Discrete mass | Generalized gastric hypertrophy |
Progressive evolution to cancer over years | Aggressive and rapid progression |
What Is the Vascular Supply to the Stomach?
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.
Why Do Patients with Gastric Cancer Get Iron Deficiency Anemia?
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.