Stomach Cancer

 

Stomach Cancer

Stomach cancer is a disease in which malignant (cancerous) cells form in the lining of the stomach. Age, diet, and stomach disease can affect your risk of developing stomach cancer. Symptoms of stomach cancer include indigestion and stomach discomfort or pain

What is stomach cancer? Cancer begins when cells in the body begin to grow out of control. Cells in almost any part of the body can become cancerous and then spread to other areas of the body. To learn more about cancer and how it starts and spreads, see What is cancer? Stomach cancer, also called gastric cancer, begins when cells in the stomach begin to grow out of control. Belly To understand stomach cancer, it helps to know about the normal structure and function of the stomach. color illustration of the digestive system showing the location of the esophagus, stomach, pancreas, transverse colon, descending colon, sigmoid colon, anus, rectum, cecum, cecum, ascending colon, small intestine, gallbladder, and liver The stomach is a sac-like organ that is an important part of the digestive system. After chewing and swallowing, food enters the esophagus, a tube that carries food through the throat and chest to the stomach. The esophagus joins the stomach at the gastroesophageal (GE) junction, which is just below the diaphragm (the thin layer of respiratory muscle below the lungs). The stomach then begins to digest the food by secreting gastric juice. Food and gastric juices mix and then empty into the first part of the small intestine called the duodenum. Some people use the word "stomach" to refer to the abdominal area. The medical term for this area is the abdomen. For example, some people with pain in this area would say that their "stomach hurts", when in fact the pain may be coming from some other organ in the area. Doctors would call this symptom "abdominal pain" because the stomach is only one of many organs in the abdomen. Stomach cancer is different from other cancers that can occur in the abdomen, such as cancer of the colon or rectum (colon), liver, pancreas, or small intestine. These cancers can have different symptoms, different outlooks and different treatments. Parts of the stomach The stomach has 5 parts. illustration showing body of stomach, fundus, cardia, pylorus and antrum The first 3 parts make up the proximal stomach: Cardia: the first part closest to the esophagus Fundus: the upper part of the stomach next to the cardia Body (corpus): the main part of the stomach, between the upper and lower parts Certain cells in these parts of the stomach make acid and pepsin (a digestive enzyme), which combine to make gastric juice that helps digest food. They also make a protein called intrinsic factor, which the body needs to absorb vitamin B12. The lower 2 parts make up the distal stomach: Antrum: the lower part (near the small intestine) where food mixes with gastric juice Pylorus: the last part of the stomach that acts as a valve to control the emptying of stomach contents into the small intestine Other organs near the stomach include the small intestine, large intestine, liver, spleen, and pancreas. The stomach wall has 5 layers: illustration showing the stomach with a detailed cross-section of its layers: mucosa, submucosa, and serosa The innermost layer is the mucous membrane. This is where stomach acid and digestive enzymes are formed. Most stomach cancers start in this layer. Next is the supporting layer called the submucosa. Beyond that is the propria, a thick layer of muscle that helps move and mix the contents of the stomach. The outer 2 layers, and outer serosa, cover the stomach. The layers are important in determining the stage (extent) of the cancer, which can affect treatment options and a person's prognosis (outlook). As the cancer grows from the mucosa into deeper layers, the stage becomes more advanced and treatment can be more extensive. The development of stomach cancer Stomach cancers tend to develop slowly over many years. Before actual cancer develops, precancerous changes often occur in the inner lining (mucosa) of the stomach. These early changes rarely cause symptoms, so they often go undetected. Cancers starting in different parts of the stomach can cause different symptoms and have different outcomes. The location of the cancer can also affect treatment options. For example, cancers that start or grow in the GE junction are usually staged and treated the same as esophageal cancers. (See Esophageal Cancer for more information.) Types of stomach cancer Adenocarcinomas Most stomach cancers (about 90% to 95%) are adenocarcinomas. These cancers develop from glandular cells in the innermost lining of the stomach (mucosa). If you are told you have stomach cancer (or stomach cancer), it will almost always be adenocarcinoma. The information on the following pages about stomach cancer is specific to this type of cancer. There are 2 main types of gastric adenocarcinomas: The intestinal type tends to have a slightly better prognosis (outlook). Cancer cells are more likely to have certain gene changes that could allow treatment with targeted drug therapy. The diffuse type tends to spread faster. It is less common than the intestinal type and tends to be more difficult to treat. Other types of cancer that can start in the stomach Gastrointestinal stromal tumors (GIST) These unusual tumors begin in very early forms of cells in the stomach wall called interstitial cells of Cajal. Some GISTs are much more likely than others to grow into other areas or spread to other parts of the body. Although GISTs can start anywhere in the digestive tract, most start in the stomach. See Gastrointestinal stromal tumor (GIST) for more information. Neuroendocrine tumors (including carcinoids) Neuroendocrine tumors (NETs) start in cells of the stomach (or other parts of the digestive tract) that behave like nerve cells in some ways and hormone-making (endocrine) cells in others. Most NETs tend to grow slowly and do not spread to other organs, but some can grow and spread quickly. NETs are discussed in more detail in Gastrointestinal neuroendocrine (carcinoid) tumors. Lymphomas These cancers begin in immune system cells called lymphocytes. Lymphomas usually start in other parts of the body, but some can start in the stomach wall. The treatment and outlook for these cancers depends on the type of lymphoma and other factors. For more information, see Non-Hodgkin's lymphoma. Other cancers Other types of cancer, such as squamous cell carcinomas, small cell carcinomas, and leiomyosarcomas, can also start in the stomach, but these cancers are very rare. American Cancer Society medical and editorial staff Our team consists of doctors and oncology certified nurses with in-depth knowledge of oncology care, as well as journalists, editors and translators with extensive experience in medical writing.