There are several types of stomach cancer, but most cases are considered adenocarcinomas.
Stomach cancer begins when cells of the stomach start to grow at an uncontrolled rate. In adenocarcinomas of the stomach, the cancer begins developing in the mucosa, which are gland cells in the innermost lining of the stomach. Stomach cancer is the fifth most common cancer type worldwide.
Adenocarcinomas, which account for nearly 90% of all stomach cancer cases, can be divided into two main types, intestinal and diffuse. Intestinal adenocarcinomas have a more favorable prognosis. These tumors are often associated with biomarkers that allow for targeted therapy treatment.
Intestinal adenocarcinomas are more often associated with the helicobacter pylori infection, one of the main risk factors of stomach cancer. Diffuse adenocarcinomas are typically more aggressive and difficult to treat but are also less common than intestinal adenocarcinomas. Hereditary gastric cancer refers to families with more than one case of diffuse adenocarcinomas under the age of 40.
Other cancer types that can start in the stomach include:
- Gastrointestinal stromal tumors (GIST): This rare form of cancer starts developing in interstitial cells of Cajal that are in the wall of the stomach. These tumors can grow in other parts of the digestive tract, but most cases occur in the stomach.
- Neuroendocrine tumors: Begin in the digestive tract or the cells of the stomach that make hormones.
- Lymphomas: Normally occur in lymphocytes around the body but can sometimes develop in the wall of the stomach.
Although rare, other cancer types do occur in the stomach such as squamous cell carcinomas, small cell carcinomas, and leiomyosarcomas.
Types of Stomach Cancer Treatment
The stomach cancer treatment that is utilized depends on factors such as the location of the cancer and stage of disease. Surgery is commonly used for early-stage patients, when the cancer has not spread to the tissues surrounding the stomach.
Other common treatments for all stomach cancer types include:
- Targeted drug therapy
- Radiation therapy
Surgery offers the best chance for successful treatment if the cancer has not spread. Chemotherapy or radiation are often given before and after the procedure. The subtype of the stomach cancer usually does not affect the decision for which treatment is used.