[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.

[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.

By the time symptoms are recognized, the cancer has often reached an advanced stage (see below) and may have metastasized (spread to other, perhaps distant, parts of the body), which is one of the main reasons for its relatively poor prognosis.

[25][26] 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.

[46] However, the risk of gastric cardia adenocarcinoma, with GERD present, has been found to increase more than two times for an obese person.

[52] To find the cause of symptoms, the doctor asks about the patient's medical history, does a physical examination, and may order laboratory studies.

[53] The patient may also have one or all of these exams: In 2013, Chinese and Israeli scientists reported a successful pilot study of a breathalyzer-style breath test intended to diagnose stomach cancer by analyzing exhaled chemicals without the need for an intrusive endoscopy.

[37] Various gastroscopic modalities have been developed to increase yield of detected mucosa with a dye that accentuates the cell structure and can identify areas of dysplasia.

The surgeon removes nearby lymph nodes and possibly samples of tissue from other areas in the abdomen for examination by a pathologist.

[74] 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.

[82] New treatment approaches such as immunotherapy or gene therapy and improved ways of using current methods are being studied in clinical trials.

[84] Post-operatively, up to 70% of people undergoing total gastrectomy develop complications such as dumping syndrome and reflux esophagitis.

[85] Construction of a "pouch", which serves as a "stomach substitute", reduced the incidence of dumping syndrome and reflux esophagitis by 73% and 63% respectively, and led to improvements in quality-of-life, nutritional outcomes, and body mass index.

[85] Proximal gastrectomy (PG) can be considered a viable alternative for upper third early gastric cancer (EGC)[86] Of the different surgical techniques, endoscopic mucosal resection (EMR) is a treatment for early gastric cancer (tumor only involves the mucosa) that was pioneered in Japan and is available in the United States at some centers.

[6] Endoscopic submucosal dissection is a similar technique pioneered in Japan, used to resect a large area of mucosa in one piece.

[13] Unfortunately, stomach cancer has not been particularly sensitive to these drugs, and chemotherapy, if used, has usually served to palliatively reduce the size of the tumor, relieve symptoms of the disease, and increase survival time.

], treatment with human epidermal growth factor receptor 2 (HER2) inhibitor, trastuzumab, has been demonstrated to increase overall survival in inoperable locally advanced or metastatic gastric carcinoma over-expressing the HER2/neu gene.

[89] A recent clinical study reported promising results for a combination therapy using Nivolumab and Anlotinib in the treatment of advanced gastric adenocarcinoma (GAC) and esophageal squamous cell carcinoma (ESCC), that improve the immune response against cancer while simultaneously slowing tumor progression.

[90] The research, conducted by Zhongshan Hospital, Fudan University, and BGI Genomics, was published in Nature Communications in October 2024.

The study evaluated the efficacy of combining Nivolumab, an immunotherapy that enhances the immune system's ability to attack cancer cells, with anlotinib hydrochloride, a drug that inhibits tumor angiogenesis by blocking signals essential for the growth of new blood vessels.

[15] 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.

[107] Gastric cancer, though present, is relatively low when compared to countries with high incidence like Japan and China.

The trend commonly seen is that H. pylori infection increases the risk for gastric cancer, but this is not the case in Africa, giving this phenomenon the name the "African enigma".

[108] Increasing access to health care and treatment measures have been commonly associated with the rising incidence, though, particularly in Uganda.

[107] The stomach is a muscular organ of the gastrointestinal tract that holds food and begins the digestive process by secreting gastric juice.

Signs vary, but may include vomiting (especially if blood is present), weight loss, anemia, and lack of appetite.

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.

[109] Most stomach tumors are malignant with evidence of spread to lymph nodes or liver, making treatment difficult.

[citation needed] A carcinogenic interaction was demonstrated between bile acids and Helicobacter pylori in a mouse model of gastric cancer.