The stomach cancer is a form of cancer developing at the expense of the tissues of the stomach. By definition, patients with gastric cancer is epithelial whose center is more than 2 cm below the oesophago-gastric. Lesions located above this limit are classified as tumors of the cardia, whose treatment is specific.
The stomach cancer is the second leading cause of cancer death worldwide. They are more common in Japan, China, Chile and Ireland. The annual incidence of stomach cancer is decreasing steadily for twenty years. In France it is currently 7 to 8 000 new cases per year. In contrast, the incidence of cancers of the cardia is increasing.
The 5-year survival is 10 to 15%. 80% are diagnosed after the age of 65 years. Two-thirds are at an advanced stage.
The stomach cancer is statistically linked to a low socio-economic patterns and specific food (smoking, salting). The environmental risk factors are:
* Low socio-economic
* Low consumption of vitamin A and C (fresh), nitrate consumption, salt diet
The conditions favoring the stomach cancer are:
* History of gastric surgery
* Inflammation of the stomach (gastritis) infections including Helicobacter pylori, but some types of Helicobacter be more harmful.
Finally, there are genetic predisposition to gastric cancer (less than 3% of cases):
* Adenomatous polyposis family rectocolique
* Juvenile polyposis
* Hereditary diffuse gastric cancer (mutation of E.cadherine constituting one third of the genetic forms).
The disparity in the incidence of cancer by geography is probably more of an environmental factor that a genetic factor, as can attest the evolution of the frequency of disease among migrant children.
It is adenocarcinoma in 85% of cases. 2 forms are recognized:
* Intestinal forms (rather well differentiated), which describes the development of different forms: superficial or invasive, or ulcerated vegetating;
* The gastric linitis, diagnostic macroscopic (rigid wall with thickened whitish appearance of linen).
The independent cell signet-ring are in favor of gastric linitis but not exclusive.
Other histological types are rarely found in less than 15% of cases, lymphoma (MALT type, for example) and in 1 to 3% of cases, sarcomas (especially with GIST) and metastasis of other tumors.
There are two systems of classification of gastric tumors, the Japanese and the much more used in Europe to America, called the TNM classification, described below.
T0 no tumor
Tis tumor in situ
T1 extension to the mucosa or submucosa
T2 extending to the muscularis
T3 extending to the serosa
T4 extension to adjacent organs (spleen, transverse colon, liver, diaphragm, pancreas, abdominal wall, adrenal, kidney, small intestine and retroperitoneum)
N0 no lymph node
N1 lymph proximal
N2 lymph nodes regional
N3 lymph distance (liver, spleen)
M0 no metastases
M1 metastasis (including lymph node of Troisier)
Epigastric pain, weight loss belly and signs of anemia are the symptoms most often found. The abdomen may also swell significantly but the specificity remains low to evoke this condition. Delayed diagnosis is estimated at one year after the first clinical symptoms.
The diagnosis of gastric cancer is often delayed given the depth of the tumor and the absence of symptoms of small lesions. The examinations are essential to the diagnosis of gastric endoscopy and computed tomography thoraco-abdominopelvic.
Different tumor markers have little interest in screening or monitoring of cancer.
Read also Cancer