Stomach cancer
Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach.[10] Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas.[2] Lymphomas and mesenchymal tumors may also develop in the stomach.[2] Early symptoms may include heartburn, upper abdominal pain, nausea, and loss of appetite.[1] Later signs and symptoms may include weight loss, yellowing of the skin and whites of the eyes, vomiting, difficulty swallowing, and blood in the stool, among others.[1] 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.[11]
Stomach cancer
Gastric cancer
Over years[2]
Gastric carcinomas, lymphoma, mesenchymal tumor[2]
Smoking, dietary factors such as pickled vegetables, obesity[2][4]
Mediterranean diet, not smoking[2][5]
Surgery, chemotherapy, radiation therapy, targeted therapy[1]
Five-year survival rate:
< 10% (advanced cases),[6]
32% (US),[7] 71% (Japan)[8]
968,350 (2022)[9]
659,853 (2022)[9]
The most common cause is infection by the bacterium Helicobacter pylori, which accounts for more than 60% of cases.[2][3][12] Certain strains of H. pylori have greater risks than others.[2] Smoking, dietary factors such as pickled vegetables and obesity are other risk factors.[2][4] About 10% of cases run in families, and between 1% and 3% of cases are due to genetic syndromes inherited such as hereditary diffuse gastric cancer.[2] Most of the time, stomach cancer develops in stages over years.[2] Diagnosis is usually by biopsy done during endoscopy.[1] This is followed by medical imaging to determine if the disease has spread to other parts of the body.[1] Japan and South Korea, two countries that have high rates of the disease, screen for stomach cancer.[2]
A Mediterranean diet lowers the risk of stomach cancer, as does not smoking.[2][5] Tentative evidence indicates that treating H. pylori decreases the future risk.[2][5] If stomach cancer is treated early, it can be cured.[2] Treatments may include some combination of surgery, chemotherapy, radiation therapy, and targeted therapy.[1][13] For certain subtypes of gastric cancer, cancer immunotherapy is an option as well.[14] If treated late, palliative care may be advised.[2] Some types of lymphoma can be cured by eliminating H. pylori.[15] Outcomes are often poor, with a less than 10% five-year survival rate in the Western world for advanced cases.[6] This is largely because most people with the condition present with advanced disease.[6] In the United States, five-year survival is 31.5%,[7] while in South Korea it is over 65% and Japan over 70%, partly due to screening efforts.[2][8]
Globally, stomach cancer is the fifth-leading type of cancer and the third-leading cause of death from cancer, making up 7% of cases and 9% of deaths.[16] In 2018, it newly occurred in 1.03 million people and caused 783,000 deaths.[17] Before the 1930s, it was a leading cause of cancer deaths in the Western world, however rates have sharply declined among younger generations in the West, while they remain high for people living in East Asia.[18][19][20] The decline in the West is believed to be due to the decline of salted and pickled food consumption, as a result of the development of refrigeration as a method of preserving food.[21] Stomach cancer occurs most commonly in East Asia, followed by Eastern Europe.[2] It occurs twice as often in males as in females.[2]
Prevention[edit]
Getting rid of H. pylori in those who are infected decreases the risk of stomach cancer.[84] A 2014 meta-analysis of observational studies found that a diet high in fruits, mushrooms, garlic, soybeans, and green onions was associated with a lower risk of stomach cancer in the Korean population.[85] Low doses of vitamins, especially from a healthy diet, decrease the risk of stomach cancer.[86] A previous review of antioxidant supplementation did not find supporting evidence and possibly worse outcomes.[87][88] Modern technology is used to promote early diagnosis, e.g. based on serum markers.[89]
Prognosis[edit]
The prognosis of stomach cancer is generally poor, because the tumor has often metastasized by the time of discovery, and most people with the condition are elderly (median age is between 70 and 75 years) at presentation.[99] The average life expectancy after being diagnosed is around 24 months, and the five-year survival rate for stomach cancer is less than 10%.[6]
Almost 300 genes are related to outcomes in stomach cancer, with both unfavorable genes where high expression is related to poor survival and favorable genes where high expression is associated with longer survival times.[100][101] Examples of poor prognosis genes include ITGAV, DUSP1 and P2RX7.[102]
Other animals[edit]
The stomach is a muscular organ of the gastrointestinal tract that holds food and begins the digestive process by secreting gastric juice. The most common cancers of the stomach are adenocarcinomas, but other histological types have been reported. Signs vary, but may include vomiting (especially if blood is present), weight loss, anemia, and lack of appetite. Bowel movements may be dark and tarry in nature. To determine whether cancer is present in the stomach, special X-rays and/or abdominal ultrasounds may be performed. Gastroscopy, a test using an endoscope to examine the stomach, is a useful diagnostic tool that can also take samples of the suspected mass for histopathological analysis to confirm or rule out cancer. The most definitive method of cancer diagnosis is through open surgical biopsy.[116] Most stomach tumors are malignant with evidence of spread to lymph nodes or liver, making treatment difficult. Except for lymphoma, surgery is the most frequent treatment option for stomach cancers but it is associated with significant risks.
A carcinogenic interaction was demonstrated between bile acids and Helicobacter pylori in a mouse model of gastric cancer.[117][118]