colloid, linitis plastica or leather-bottle stomach) tumour cells are discohesive and secrete mucus, which is delivered in the interstitium, producing large pools of mucus/colloid (optically "empty" spaces). it is poorly differentiated. in signet-ring cell carcinomas, the mucus remains inside the tumour cell and pushes the nucleus to the periphery, giving rise to signet-ring cells. around 5% of gastric cancers are lymphomas. these may include extranodal marginal zone b-cell lymphomas (malt type) and to a lesser extent diffuse large b-cell lymphomas. malt type make up about half of stomach lymphomas. carcinoid and stromal tumors may occur. poor to moderately differentiated adenocarcinoma of the stomach. h&e stain. gastric signet ring cell carcinoma. h&e stain. adenocarcinoma of the stomach and intestinal metaplasia. h&e stain. staging t stages of stomach cancer if cancer cells are found in the tissue sample, the next step is to stage, or find out the extent of the disease. various tests determine whether the cancer has spread, and if so, what parts of the body are affected. because stomach cancer can spread to the liver, pancreas, and other organs near the stomach, as well as to the lungs, the doctor may order a ct scan, a pet scan, an endoscopic ultrasound exam, or other tests to check these areas. blood tests for tumor markers, such as carcinoembryonic antigen and carbohydrate antigen may be ordered, as their levels correlate to extent of metastasis, especially to the liver, and the cure rate. staging may not be complete until after surgery. the surgeon removes nearby lymph nodes and possibly samples of tissue from other areas in the abdomen for examination by a pathologist. the clinical stages of stomach cancer are: stage 0 – limited to the inner lining of the stomach, it is treatable by endoscopic mucosal resection when found very early (in routine screenings), or otherwise by gastrectomy and lymphadenectomy without need for chemotherapy or radiation. stage i – penetration to the second or third layers of the stomach (stage 1a) or to the second layer and nearby lymph nodes (stage 1b): stage 1a is treated by surgery, including removal of the omentum. stage 1b may be treated with chemotherapy (5-fluorouracil) and radiation therapy. stage ii – penetration to the second layer and more distant lymph nodes, or the third layer and only nearby lymph nodes, or all four layers but not the lymph nodes, it is treated as for stage i, sometimes with additional neoadjuvant chemotherapy. stage iii – penetration to the third layer and more distant lymph nodes, or penetration to the fourth layer and either nearby tissues or nearby or more distant lymph nodes, it is treated as for stage ii; a cure is still possible in some cases. stage iv – cancer has spread to nearby tissues and more distant lymph nodes, or has metastasized to other organs. a cure is very rarely possible at this stage. some other techniques to prolong life or improve symptoms are used, including laser treatment, surgery, and/or stents to keep the digestive tract open, and chemotherapy by drugs such as 5-fluorouracil, cisplatin, epirubicin, etoposide, docetaxel, oxaliplatin, capecitabine, or irinotecan. stomach cancer metastasized to the lungs the tnm staging system is also used. in a study of open-access endoscopy in scotland, patients were diagnosed 7% in stage i, 17% in stage ii, and 28% in stage iii. a minnesota population was diagnosed 10% in stage i, 13% in stage ii, and 18% in stage iii. however, in a high-risk population in the valdivia province of southern chile, only 5% of patients were diagnosed in the first two stages and 10% in stage iii. prevention getting rid of h. pylori in those who are infected decreases the risk of stomach cancer. 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. low doses of vitamins, especially from a healthy diet, decrease the risk of stomach cancer. a previous review of antioxidant supplementation did not find supporting evidence and possibly worse outcomes. modern technology is used to promote early diagnosis, e.g. based on serum markers. management cancer of the stomach is difficult to cure unless it is found at an early stage (before it has begun to spread). unfortunately, because early stomach cancer causes few symptoms, the disease is usually advanced when the diagnosis is made. treatment for stomach cancer may include surgery, chemotherapy, or radiation therapy. new treatment approaches such as immunotherapy or gene therapy and improved ways of using current methods are being studied in clinical trials. surgery anatomy before roux-en-y surgery to resect stomach cancer surgery remains the only curative therapy for stomach cancer. 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. in emr, the tumor, together with the inner lining of stomach (mucosa), is removed from the wall of the stomach using an electrical wire loop through the endoscope. the advantage is that it is a much smaller operation than removing the stomach. endoscopic submucosal dissection is a similar technique pioneered in japan, used to resect a large area of mucosa in one piece. if the pathologic examination of the resected specimen shows incomplete resection or deep invasion by tumor, the patient would need a formal stomach resection. a 2016 cochrane review found low-quality evidence of no difference in short-term mortality between laparoscopic and open gastrectomy (removal of stomach), and that benefits or harms of laparoscopic gastrectomy cannot be ruled out. post-operatively, up to 70% of people undergoing total gastrectomy develop complications such as dumping syndrome and reflux esophagitis. 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. those with metastatic disease at the time of presentation may receive palliative surgery, and while it remains controversial, due to the possibility of complications from the surgery itself and because it may delay chemotherapy, the data so far are mostly positive, with improved survival rates being seen in those treated with this approach. chemotherapy the use of chemotherapy to treat stomach cancer has no firmly established standard of care. 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. some drugs used in stomach cancer treatment have included: fluorouracil or its analog capecitabine, bcnu (carmustine), methyl-ccnu (semustine) and doxorubicin (adriamycin), as well as mitomycin c, and more recently cisplatin and taxotere, often using drugs in various combinations. the relative benefits of these different drugs, alone and in combination, are unclear. clinical researchers are exploring the benefits of giving chemotherapy before surgery to shrink the tumor, or as adjuvant therapy after surgery to destroy remaining cancer cells. targeted therapy recently, 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. in particular, her2 is overexpressed in 13–22% of patients with gastric cancer. of note, her2 overexpression in gastric neoplasia is heterogeneous and comprises a minority of tumor cells (less than 10% of gastric cancers overexpress her2 in more than 5% of tumor cells). hence, this heterogeneous expression should be taken into account for her2 testing, particularly in small samples such as biopsies, requiring the evaluation of more than one bioptic sample. radiation radiation therapy (also called radiotherapy) may be used to treat stomach cancer, often as an adjuvant to chemotherapy and/or surgery. lymphoma malt lymphomas are often completely resolved after the underlying h. pylori infection is treated. this results in remission in about 80% of cases. prognosis 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. the average life expectancy after being diagnosed is around 24 months, and the five-year survival rate for stomach cancer is less than 10%. 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. examples of poor prognosis genes include itgav, dusp1 and p2rx7. epidemiology stomach cancer deaths per million persons in 2012 0–11 12–16 17–24 25–33 34–51 52–76 77–102 103–128 129–175 176–400 worldwide, stomach cancer is the fifth most-common cancer with 952,000 cases diagnosed in 2012. it is more common both in men and in developing countries. in 2012, it represented 8.5% of cancer cases in men, making it the fourth-most common cancer in men. also in 2012, the number of deaths was 700,000, having decreased slightly from 774,000 in 1990, making it the third-leading cause of cancer-related death (after lung cancer and liver cancer). less than 5% of stomach cancers occur in people under 40 years of age, with 81.1% of that 5% in the age-group of 30 to 39 and 18.9% in the age-group of 20 to 29. in 2014, stomach cancer resulted in 0.61% of deaths (13,303 cases) in the u.s. in china, stomach cancer accounted for 3.56% of all deaths (324,439 cases). the highest rate of stomach cancer was in mongolia, at 28 cases per 100,000 people. in the united kingdom, stomach cancer is the 15th-most common cancer (around 7,100 people were diagnosed with stomach cancer in 2011), and it is the 10th-most common cause of cancer-related deaths (around 4,800 people died in 2012). incidence and mortality rates of gastric cancer vary greatly in africa. the globocan system is currently the most widely used method to compare these rates between countries, but african incidence and mortality rates are seen to differ among countries, possibly due to the lack of universal access to a registry system for all countries. variation as drastic as estimated rates from 0.3/100000 in botswana to 20.3/100000 in mali have been observed. in uganda, the incidence of gastric cancer has increased from the 1960s measurement of 0.8/100000 to 5.6/100000. gastric cancer, though present, is relatively low when compared to countries with high incidence like japan and china. one suspected cause of the variation within africa and between other countries is due to different strains of the h. pylori bacteria. 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". although this bacterial species is found in africa, evidence has supported that different strains with mutations in the bacterial genotype may contribute to the difference in cancer development between african countries and others outside the continent. increasing access to health care and treatment measures have been commonly associated with the rising incidence, though, particularly in uganda. other animals 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. 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.