Stomach cancer is the second most frequent form of cancer globally, however, it proves far less common in the United States. The American Cancer Society reports approximately 22,220 new cases of stomach cancer will occur in the United States in 2014, more commonly occurring in men. Known risk factors contributing to the development of stomach cancer include smoking, infection with the bacterium Helicobacter pylori, and poor dietary intake of fresh fruits and vegetables.
Adenocarcinomas comprise approximately 90 to 95 percent of stomach cancers in the United States. These cancers arise from the cells that form the lining of the stomach. The growth pattern of gastric adenocarcinomas varies. Tumors may amass on the inner surface of the stomach creating a ball-like growth that protrudes into the open space of the stomach. Spreading gastric adenocarcinomas are flat and extend along the stomach lining. Ulcerating tumors grow into the stomach wall with an open sore-like lesion on the stomach lining surface. Surgical removal of gastric adenocarcinoma provides the greatest opportunity for cure among people with disease limited to the stomach. Radiation therapy and chemotherapy may also be utilized for gastric adenocarcinoma treatment.
Cancers arising from the lymphocytes -- a type of immune system cell -- are termed lymphomas. While most lymphomas begin in the lymph nodes, they may occur in lymphatic tissues outside the lymph nodes. The stomach proves the most frequent site of extranodal lymphoma. Stomach infection with the bacterium Helicobacter pylori may contribute to the development of gastric lymphoma. This bacteria is also strongly associated with adenocarcinoma development. Symptoms of gastric lymphoma frequently mimic those of peptic ulcer disease and include swallowing difficulties, abdominal pain, nausea, vomiting and unintentional weight loss. Gastric lymphoma is uncommon, comprising approximately 4 percent of stomach cancers in the United States.
Gastrointestinal Stromal Tumors
Gastrointestinal stromal tumors arise from a specialized type of nerve cells that control the muscular activity of the digestive system. Although these slow-growing tumors can arise in any location within the gastrointestinal system, the stomach is most commonly affected. Possible symptoms include abdominal discomfort, loss of appetite, nausea, vomiting and unintentional weight loss. Gastrointestinal stromal tumors may be cancerous or noncancerous. The American Cancer Society reports gastrointestinal stromal tumors are rare -- data indicate approximately 4,500 to 6,000 new cases occur annually in the United States.