Gastrointestinal Stromal Tumor - GIST: Stages

Approved by the Cancer.Net Editorial Board, 03/2017

ON THIS PAGE: You will learn about how doctors describe a tumor’s growth or spread. This is called the stage. Use the menu to see other pages.

Staging is a way of describing where the tumor is located, or if it has spread to another part of the body from where it started. If this happens, it is called metastasis. Doctors may also do tests to learn which treatments could work best.

Doctors use diagnostic tests to find out the tumor's stage, so staging may not be complete until all the tests are finished. Tests that may be used to find the stage include CT scan, MRI, or PET-CT scan (see Diagnosis). Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis. There are different stage descriptions for different types of cancer.

For other types of GI tumors, the most common staging tool used is called the TNM system. TNM is an abbreviation for tumor (T), node (N), and metastasis (M). However, the use of the TNM system for GIST is not required. Instead, doctors look at different factors to determine a patient’s prognosis and the specific risk of how aggressive an individual tumor will be. Specifically, doctors want to figure out how quickly the GIST may grow and the chance the tumor will come back, or recur, after surgery.

Doctors commonly use the factors listed below to determine how aggressive a GIST that has been removed could be:

  • The size of the tumor

  • The mitotic count, which describes the number of dividing cells

  • The location where the tumor started

A GIST that has spread to distant areas of the body is considered higher risk because it has a greater likelihood of coming back, called recurrent GIST.

Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Treatment Options. You may use the menu to choose a different section to read in this guide.