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Stomach cancer, also known as gastric cancer, is cancer developing from the lining of the stomach.〔(【引用サイトリンク】url=http://www.cancer.gov/cancertopics/types/stomach )〕 Early symptoms may include heartburn, upper abdominal pain, nausea and loss of appetite. Later signs and symptoms may include weight loss, yellow skin and whites of the eyes, vomiting, difficulty swallowing, and blood in the stool among others. The cancer may spread from the stomach to other parts of the body, particularly the liver, lungs, bones, lining of the abdomen and lymph nodes. The most common cause is infection by the bacterium ''Helicobacter pylori'', which accounts for more than 60% of cases.〔 Certain types of ''H. pylori'' have greater risks than others. Other common causes include eating pickled vegetables and smoking. About 10% of cases run in families and between 1% and 3% of cases are due to genetic syndromes inherited from a person's parents such as hereditary diffuse gastric cancer. Most cases of stomach cancers are gastric carcinomas. This type can be divided into a number of subtypes. Lymphomas and mesenchymal tumors may also develop within the stomach. Most of the time, stomach cancer develops through a number of stages over a number of years.〔 Diagnosis is usually by biopsy done during endoscopy. This is then followed by medical imaging to determine if the disease has spread to other parts of the body.〔 Japan and South Korea, two countries that have high rates of disease, screen for stomach cancer.〔 A Mediterranean diet lowers the risk of cancer as does the stopping of smoking. There is tentative evidence that treating ''H. pylori'' decreases the future risk.〔 If cancer is treated early, many cases can be cured.〔 Treatments may include some combination of surgery, chemotherapy, radiation therapy, and targeted therapy.〔 If treated late, palliative care may be advised.〔 Outcomes are often poor with a less than 10% 5-year survival rate globally. This is largely because most people with the condition present with advanced disease. In the United States 5-year survival is 28%〔(【引用サイトリンク】url=http://seer.cancer.gov/statfacts/html/stomach.html )〕 while in South Korea it is over 65% partly due to screening efforts.〔 Globally stomach cancer is the fifth leading cause of cancer and the third leading cause of death from cancer making up 7% of cases and 9% of deaths.〔 In 2012 it occurred in 950,000 people and caused 723,000 deaths. Before the 1930s in much of the world, including most Western developed countries, it was the most common cause of death from cancer. Rates of death have been decreasing in many areas of the world since then.〔 This is believed to be due to the eating of less salted and pickled foods as a result of the development of refrigeration as a method of keeping food fresh. Stomach cancer occurs most commonly in East Asia and Eastern Europe and it occurs twice as often in males as in females. ==Signs and symptoms== Stomach cancer is often either asymptomatic (producing no noticeable symptoms) or it may cause only nonspecific symptoms (symptoms that are specific not only to stomach cancer, but also to other related or unrelated disorders) in its early stages. By the time symptoms occur, the cancer has often reached an advanced stage (see below) and may have also metastasized (spread to other, perhaps distant, parts of the body), which is one of the main reasons for its relatively poor prognosis.〔(【引用サイトリンク】title=Statistics and outlook for stomach cancer )〕 Stomach cancer can cause the following signs and symptoms: Early cancers may be associated with indigestion or a burning sensation (heartburn). However, less than 1 in every 50 people referred for endoscopy due to indigestion has cancer.〔(【引用サイトリンク】title=Guidance on Commissioning Cancer Services Improving Outcomes in Upper Gastro-intestinal Cancers )〕 Abdominal discomfort and loss of appetite, especially for meat, can occur. Gastric cancers that have enlarged and invaded normal tissue can cause weakness, fatigue, bloating of the stomach after meals, abdominal pain in the upper abdomen, nausea and occasional vomiting, diarrhea or constipation. Further enlargement may cause weight loss or bleeding with vomiting blood or having blood in the stool, the latter apparent as black discolouration (melena) and sometimes leading to anemia. Dysphagia suggests a tumour in the cardia or extension of the gastric tumour into the esophagus. Note that these can be symptoms of other problems such as a stomach virus, gastric ulcer, or tropical sprue. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Stomach cancer」の詳細全文を読む スポンサード リンク
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