The stomach is the sac that holds and helps the body digest food. When food is swallowed, it goes down a tube called the esophagus. The esophagus carries it to the stomach. The stomach adds chemicals and fluids to food that help start the process of digestion. There's a strong muscle layer of the stomach. It squeezes and mixes the contents to make it soft. Food then leaves the stomach and goes into the small intestine.

In most cases, stomach cancer starts in the stomach’s inner lining, called the mucosa. This type of stomach cancer is called adenocarcinoma.

Cancer cells can then spread through the other layers of the stomach. If cancer cells reach the stomach’s outer layer, they can invade nearby organs.

Stomach cancer can also spread from the stomach to other parts of the body. This spread is called metastasis. The more cancer spreads, the harder it is to treat.

You and your healthcare provider will discuss a treatment plan that’s best for you. Treatment choices may include:

• Surgery to remove the part of the stomach with cancer and some nearby tissue. Sometimes the whole stomach must be removed (called gastrectomy).

• Chemotherapy (chemo) uses strong medicines that kill cancer cells. Many times, a combination of medicines is used. Chemo is most often given after surgery or along with radiation.

• Targeted therapy uses medicines that focus on changes in the cancer cells. This helps save normal cells while killing cancer cells. It may be used for advanced stomach cancer.
• Immunotherapy may also be used for advanced stomach cancers when other treatments don't work. These medicines boost the natural immune system so it can better kill cancer cells.

• Radiation therapy uses focused rays of energy to kill cancer cells.