Table of Contents
Stomach Cancer Definition
Malignant growths that occur in the STOMACH. Stomach CANCER is seventh among deaths from cancer in the United States. About 90 percent of stomach cancers are adenocarcinomas, malignant growths that originate in the glandular cells that carpet the gastric mucosa. These are the cells that produce the stomach’s acid and mucus, as well as DIGESTIVE ENZYMES. Though stomach cancer readily metastasizes (spreads) to other tissues and organs, the stomach is seldom the site of secondary cancers that originate elsewhere in the body.
Though the causes of stomach cancer remain a mystery, researchers do know certain factors alter the DNA of cells in the stomach in ways that result in the uncontrolled growth that characterizes cancer. These factors cause chronic irritation to the stomach tissues. They include
- INFECTION with HELICOBACTER PYLORI, believed to cause about 85 percent of PEPTIC ULCER DISEASE
- a diet high in red meats, well-done barbecued meats, and smoked meats and fish that contain nitrates or nitrites (which convert to carcinogenic substances during the digestive action of gastric juices) as preservatives
- the combination of cigarette smoking and excessive ALCOHOL consumption
- untreated or poorly controlled GASTROESOPHAGEAL REFLUX DISORDER (GERD) or Crohn’s disease
Symptoms of Stomach Cancer and Diagnostic Path
Symptoms of early stomach cancer are often vague and nonspecific, such as DYSPEPSIA, NAUSEA after eating, and a sense of fullness after eating only a small amount of food. Early stomach cancers often cause microscopic bleeding that a FECAL OCCULT BLOOD TEST (FOBT) can detect. As the cancer becomes more advanced, symptoms may include
- PAIN in the upper left abdomen
- VOMITING after meals
- dyspepsia that does not go away with antacids, eating, or medications to reduce acid in the stomach
- unintended weight loss
- blood in the vomit or in the stools, which may manifest as “coffee grounds” or tarry stools
- fatigue and weakness
The diagnostic path may include BARIUM SWALLOW, upper gastrointestinal ENDOSCOPY with biopsy, and COMPUTED TOMOGRAPHY (CT) SCAN or MAGNETIC RESONANCE IMAGING (MRI). The biopsy confirms the diagnosis and identifies the kind of cancer. The pathologic examination of the tissue sample also establishes the extent to which the cancer likely has spread, called cancer staging. The cancer’s stage helps determine treatment options and protocols (standards of practice), and expectations about outlook (prognosis).
Basic staging of stomach cancer
|BASIC STAGING OF STOMACH CANCER|
|stage 0||CANCER is in its earliest stages, completely confined to the gastric epithelium (lining of the STOMACH); also called CARCINOMA in situ||endoscopic resection, partial GASTRECTOMY, or total gastrectomy to remove the cancerous tumor|
|stage 1||cancer involves the gastric mucosa but remains confined to the stomach||partial or total gastrectomy with removal of adjacent fatty tissue and lymph nodes|
|stage 2||cancer extends into and beyond the MUSCLElayers of the stomach and may involve up to 15 adjacent LYMPH NODES||partial or total gastrectomy with extensive removal of adjacent fatty tissue and lymph nodes|
RADIATION THERAPY or CHEMOTHERAPY; occasionally a combination of both
|stage 3||cancer extends beyond the stomach into adjacent lymph nodes and nearby organs such as the SPLEEN, LIVER, PANCREAS, or intestine||total gastrectomy with extensive removal of adjacent fatty tissue and lymph nodes|
surgery to remove tumors in other organs
radiation therapy and chemotherapy
|stage 4||cancer has spread from the stomach to other organs throughout the body||palliative surgery, chemotherapy, or radiation therapy to relieve symptoms, obstruction, and bleeding that may occur|
Stomach Cancer Treatment Options and Outlook
The main treatment for nearly all stages of stomach cancer is surgery to remove the cancerous tumor, involved tissues, and adjacent structures such as LYMPH NODES and fatty tissue. Surgery is curative for stomach cancer detected very early (stage 0). For stage 1, 2, and 3 stomach cancers oncologists recommend CHEMOTHERAPY and RADIATION THERAPY after surgery. The chemotherapy drugs commonly used to treat stomach cancer are 5FU, cisplatin, epirubicin, and etoposide, which the oncologist may administer individually (particularly 5FU for stage 1 cancers) or in combination with one another.
The surgical options for stomach cancer include
- endoscopic resection, in which the surgeon removes the tumor and a safe margin of stomach tissue endoscopically
- partial GASTRECTOMY, in which the surgeon removes the section of stomach containing the tumor
- total gastrectomy, in which the surgeon removes the entire stomach and an area of surrounding adipose (fatty) tissue called the omentum
- lymphadenectomy, in which the surgeon removes the adjacent lymph nodes
Few lifestyle modifications beyond those to decrease the risk for recurrent or other cancers, are necessary for people who have endoscopic resections. Partial gastrectomy requires moderate changes in diet and EATING HABITS to accommodate the reduced size of the stomach, primarily a shift to eating smaller meals more frequently and reducing the amount of carbohydrates in the diet. Total gastrectomy requires significant modifications in eating habits as the surgery connects the lower end of the ESOPHAGUS to the start of the DUODENUM, leaving no reservoir for ingested food. Most people can eat only a few bites of food at a time after total gastrectomy, making eating enough to meet the body’s nutritional needs a fairly continuous process. As well, because the stomach produces the substances that make it possible for the body to absorb vitamins such as vitamin B12, people who undergo total gastrectomy need NUTRITIONAL SUPPLEMENTS.
The outlook for stage 0 stomach cancer is excellent, with a 90 percent of people who undergo surgery reaching the five-year survival mark. The outlook remains very good for stage 1 stomach cancer, with about a 70 percent five-year survival rate. More advanced stages of stomach cancer, in which the cancer spreads to involve other tissues and organs, remain difficult to treat successfully. Clinical research studies may offer the opportunity to participate in investigational treatments that extend life as well as improve QUALITY OF LIFE.
Risk Factors and Preventive Measures
As is the case with many kinds of cancer, age is the most significant risk factor. Most stomach cancers occur in people over age 60. Family history of stomach cancer or COLORECTAL CANCER (which is also an ADENOCARCINOMA of the gastrointestinal tract), long-term cigarette smoking (particularly in combination with excessive alcohol consumption) and OBESITY also raise the risk for stomach cancer. The most valuable preventive measure is FOBT to screen for the presence of blood in the gastrointestinal tract. Bleeding raises suspicion for several kinds of cancer that are highly treatable with early detection and intervention. People who have peptic ulcer disease should be tested and treated for H. pylori infection. A diet high in vegetables and low in smoked or preserved foods seems to lower the risk for stomach cancer.
See also ADENOCARCINOMA; ADENOMA-TO-ADENOCARCINOMA TRANSITION; CANCER RISK FACTORS; CANCER PREVENTION; CANCER TREATMENT OPTIONS AND DECISIONS; END OF LIFE CONCERNS; INFLAMMATORY BOWEL DISEASE (IBD); INTESTINAL POLYP; LIVER CANCER; LYMPHEDEMA; PANCREATIC CANCER; SMOKING AND CANCER; STAGING AND GRADING OF CANCER; SURGERY BENEFIT AND RISK ASSESSMENT.