Now we move on to the risk factors for different subtypes of stomach cancer.
H. pylori infection is the most common cancer risk factor for the individual variant.
Whereas, the diffuse variant of stomach cancer is not associated with H. pylori infection.
Due to successful anti-H. pylori therapies available, the incidence of intestinal variant of stomach cancer is coming down.
On the other hand, the incidence of diffuse variant is increasing.
Dietary factors such as high salt or nitrate containing foods increase the incidence of intestinal variant of stomach cancer.
Also, increased intake of smoked or packaged or processed food increases the incidence of intestinal subtype.
Smoking is also a major risk factor for the intestinal subtype of stomach cancer, and the incidence increases with the intensity and duration of smoking.
Any long-standing benign ulcers of the stomach may also increase the risk of developing intestinal subtype of stomach cancer.
On the other hand, the most important risk factor for diffuse variant of stomach cancer is genetical or familial, that is, it may be inherited from other family members.
Stomach cancer may also be classified based on their location, that is, whether it is proximally located or distally located in the stomach.
Proximally located means either in the gastroesophageal junction or cardio, whereas, distally located means either in the body or pylorus of the stomach.
This figure shows the location of gastroesophageal junction tumors, that is, the tumors located in the lower part of the esophagus, gastroesophageal junction or the upper part of the stomach. The risk factors for all these three is almost similar.
Whereas, this figure shows the location of the tumors present in the body and pylorus. The risk factors for these are different.
The intestinal subtype of stomach cancer is less commonly seen in the GE junction and proximal part of stomach, and more commonly seen in the body and pylorus.
And the diffuse variant is seen equally in the cardia, body and the pylorus of stomach.
There has been a gradual increase in the incident of GE junction and proximal stomach tumors and a gradual decrease in the tumors in the body and pylorus, Let’s understand why.
H pylori infection is very commonly seen all over the world.
Long standing infection with H. pylori leads to damage to normal epithelium of stomach, which is called as atrophic gastritis, due to which there is a decrease in gastric acid production.
Due to chronic gastritis caused by H. pylori infection, there is a increased chance of cancers in the body and pylorus of the stomach.
On the other hand, atrophic gastritis caused by chronic H. pylori infection decreases the acid production by the stomach.
It reduces the chances of GERD, thereby reducing the chances of cancer in the GE junction and the cardiac region of the stomach.
But nowadays, due to successful anti-H. pylori therapy available, the cancers in the body and the pylorus have decreased, whereas, those in the GE junction and cardia have increased.
So these were the different subtypes of stomach cancer risk factor.
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