Cancer is a disease in which cells grow in an abnormal way. Normally, the cells divide in a controlled manner. If cells keep dividing when new cells are not needed, a mass of tissue called a tumor forms.
A tumor can be benign or malignant. A benign tumor is not cancer and will not spread to other parts of the body. A malignant tumor is cancer. Cancer cells invade and damage tissue around them. They can also enter the lymph and blood streams, spreading to other parts of the body. Stomach cancer, which may also be referred to as gastric cancer, is the development of malignant cells in the stomach.
The stomach is a hollow, muscular chamber that is part of the digestive system. It is located just under the breastbone in the upper part of the abdomen. Once food is swallowed, it is carried to the stomach by a muscular tube called the esophagus. The primary function of the stomach is to start the break down of food so its nutrients can be used by the body.
The stomach is made of a number of tissue layers.
The stomach is also split into 4 sections:
Cell death and cell growth are a normal process in the body to replace old or damaged cells. The inside lining of the stomach is an active area of the body that may have a high rate of cell death and replacement. As a result, areas like this have a higher risk of cellular mutations that can lead to uncontrolled growth. Irritants introduced to the stomach and certain medical conditions can cause additional damage that requires an even higher rate of new cells. Irritants include stomach acid, alcohol, tobacco, and certain foods. Helicobacter pylori infection, which is a main cause of gastric ulcers, also contributes to irritation. These factors don't always cause cancer but may increase the risk of cancer cells developing.
Stomach cancer grows slowly and may not cause problems right away. It often starts in the inner layer, the mucosa. Eventually, the cancer will grow into surrounding tissue and through the different layers of the stomach. Once cancer has grown it will start to interfere with normal function and cause symptoms like indigestion, pain during swallowing, or weight loss. If it grows beyond the outer layer or serosa of the stomach, the cancer can spread to nearby structures, such as the liver or lungs. The cancer can also spread to lymph nodes or blood vessels, which can carry cancer cells to other areas of the body. Common sites for stomach cancer to spread to are nearby lymph nodes, the lungs, or other organs in the abdominal cavity.
The type of cancer will depend on the specific type of stomach cells that the cancer starts in. Types include:
This fact sheet focuses on adenocarcinomas.
About stomach cancer. American Cancer Society website. Available at: https://www.cancer.org/cancer/stomach-cancer/about.html. Updated February 10, 2016. Accessed September 1, 2017.
Gastric carcinoma. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T11615...astric-carcinoma. Updated September 27, 2016. Accessed September 1, 2017.
Gastric cancer. National Cancer Institute website. Available at https://www.cancer.gov/types/stomach/patient/stomach-treatment-pdq. Updated April 27, 2017. Accessed September 1, 2017.
Stomach cancer. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/gastrointestinal-disorders/tumors-of-the-gi-tract/stomach-cancer. Updated January 2017. Accessed September 1, 2017.
Last reviewed September 2017 by EBSCO Medical Review Board Michael Woods, MD, FAAP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.