Stomach cancers are categorized based on the tissues in which they begin. The most frequent form of stomach cancer develops in the stomach's glandular tissue. Adenocarcinomas are the most common type of stomach tumor, accounting for more than 95 percent of all cases.

The superficial spreading adenocarcinoma, which is uncommon in the United States but more frequent in Japan, effectively replaces the stomach's lining (mucosa) with sheets of cancerous cells.

Scirrhous carcinoma (linitis plastica) is a poorly differentiated combination of mucin-producing carcinoma cells that infiltrates the muscle wall and transforms it into hard, leatherlike scar tissue that cannot stretch or move during normal digestion (peristalsis).

A malignancy can form in lymph tissue (gastric lymphoma) or the smooth muscles of the stomach wall on rare occasions (leiomyosarcoma). In the stomach, carcinoids and plasmacytomas can form.

The disease can spread straight through the stomach wall to other organs, as well as through the lymph system to nodes in the abdomen, left side of the neck, and left armpit.

Metastases can travel to the liver, lungs, bone, and brain via the bloodstream. Metastases can also be seen in the peritoneum (the lining of the abdominal cavity) and surrounding the rectum.

Causes of Stomach Cancer 

People aged 50 to 59, workers in various industries (coal mining, nickel refining, rubber and timber processing), workers exposed to asbestos fibers, people with pernicious anemia, who are 5 to 10% more likely to develop gastric cancer, and people whose diet contains smoked, highly salted, and barbecued foods are all at a significantly higher risk.

When Japanese immigrants adopt an American diet and lifestyle, they have a tenfold lower risk of developing malignancy after two generations.

Symptoms of Stomach Cancer 

Stomach cancer symptoms are similar to those of a hiatal hernia or peptic ulcer, including a vague ache that is increased by food, nausea, heartburn, and indigestion. Antacids or H-2 blockers are commonly used to treat these symptoms, which are thought to be caused by the stress of psychosomatic sickness. Unfortunately, the short respite provided by this medication frequently causes cancer tests to be delayed.

Upper stomach discomfort, vomiting after meals, as well as weight loss are, upper abdominal pain, and vomiting after meals are noted in 80 to 90% of patients.

Mild anemia, lethargy, gastrointestinal bleeding, and blood vomiting are also possible signs of stomach cancer. Peptic ulcer disease, esophageal varices (varicose veins in the esophagus that develop and burst, a disease common in drinkers), and infrequently leiomyosarcomas can all lead to vomiting blood and rectal bleeding.

Treatment for Stomach Cancer 

Stomach cancer is a condition that is partially treatable, with over 50% of patients in the early stage being cured. However, only 10 to 20% of the cases diagnosed in the United States are in the early stages. 

More advanced malignancies have a five-year survival rate that ranges from roughly 20% for individuals with regional disease to nearly nil for those with distant metastases. Treatment for metastatic cancer can alleviate symptoms and increase survival rates, although lengthy remissions are uncommon.

The best treatment is severe surgery, which involves removing most or all of the stomach, as well as the surrounding lymph nodes (subtotal or total gastrectomy). Although radical surgery is the only treatment that can lead to a cure, other surgical techniques can play an important role in symptom relief therapy.

Treatment options include radiation and chemotherapy. In general, neither has been found to enhance the prognosis for individuals with advanced cancers, while certain people with responsive tumors may benefit.