If you have been diagnosed with one or more neuroendocrine tumors (NETs), the next step will involve finding out the extent or spread of the tumor through a process called staging. This staging information is what will help your oncologist determine the best course of treatment for you.

At Rocky Mountain Cancer Centers, we understand that staging can seem confusing. Therefore, we urge you to speak freely with your cancer care team if you have any questions or concerns you would like addressed. 

Staging Systems for Neuroendocrine Tumors

Some neuroendocrine tumors, such as those of the gastrointestinal (GI) tract and pancreas have their own staging systems based on the location and characteristics of the tumor. Other NETs use the staging system for other cancers. For example, the staging of a lung NET is the same as the staging of non-small cell lung cancer. If you have been diagnosed with a lung NET, we encourage you to visit our lung cancer staging page for more information. The information regarding staging NETs of the GI tract or pancreas can be found below. 

In regards to GI tract and pancreatic NETs, the staging system most often used is the American Joint Committee on Cancer (AJCC) TNM system. This system helps your doctor answer some very important questions:

  • Tumor (T): How large is the primary tumor? Where is it located?
  • Node (N): Has the tumor spread to the lymph nodes? If so, where and how many?
  • Metastasis (M): Has the cancer spread to other parts of the body? If so, where and how much?

The results are combined to determine the stage of cancer for each person. 

Gastrointestinal Tract NET Stages

Many gastrointestinal neuroendocrine tumors (GI NETs) are staged differently than other types of GI cancer. These include NETs of the: 

For GI NETs there are 4 stages, I through IV (1 through 4). Generally, the higher the stage number, the more the cancer has spread. 

Stomach

  • Stage I: There is a small tumor, and it has not spread elsewhere.
  • Stage II: The tumor is larger and has grown as far as the subserosa, which is behind the layer of muscle in the stomach. The cancer has not spread to the lymph nodes or elsewhere in the body.
  • Stage III: The tumor is any size, and the cancer has spread to regional lymph nodes. Or, the tumor has spread to the outside of the stomach, but the cancer has not spread to the lymph nodes or elsewhere.
  • Stage IV: There is distant metastasis.

Duodenum and ampulla of Vater (small intestine)

  • Stage I: There is a small tumor, and it has not spread elsewhere.
  • Stage II: The tumor is larger than 1 cm, or it has grown as far as the pancreas. The cancer has not spread to the lymph nodes or elsewhere in the body.
  • Stage III: The tumor is any size, and the cancer has spread to regional lymph nodes. Or, the tumor has spread to the peritoneum or other organs, but the cancer has not spread to the lymph nodes or elsewhere.
  • Stage IV: There is distant metastasis.

Jejunum and ileum (small intestine)

  • Stage I: There is a small tumor, and it has not spread elsewhere.
  • Stage II: The tumor is larger than 1 cm and has grown as far as the subserosa, which is behind the layer of muscle in the small intestine. The cancer has not spread to the lymph nodes or elsewhere in the body.
  • Stage III: The tumor is any size, and the cancer has spread to regional lymph nodes. Or, the tumor has spread to the peritoneum or to other organs or structures, but the cancer has not spread to the lymph nodes or elsewhere.
  • Stage IV: There is distant metastasis.

Appendix

  • Stage I: There is a tumor of 2 cm or less, and it has not spread elsewhere.
  • Stage II: The tumor is larger than 2 cm and has grown as far as the membrane that connects the appendix to the abdomen wall. The cancer has not spread to the lymph nodes or elsewhere in the body.
  • Stage III: The tumor is any size, and the cancer has spread to regional lymph nodes. Or, the tumor has spread to the peritoneum or beyond, but the cancer has not spread to the lymph nodes or elsewhere.
  • Stage IV: There is distant metastasis.

Colon and rectum

  • Stage I: There is a tumor of 2 cm or less, and it has not spread elsewhere.
  • Stage II: Stage II is divided into stages IIA and IIB:
    • Stage IIA: The tumor has grown into the muscle. Or it is more than 2 cm in size and has invaded the lamina propria or submucosa. The cancer has not spread.
    • Stage IIB: The tumor has spread through the muscle and into the subserosal tissue behind it. The cancer has not spread to the lymph nodes or elsewhere in the body.
  • Stage III: Stage III is divided into stages IIIA and IIIB:
    • Stage IIIA: The tumor has spread to the peritoneum or has invaded nearby organs or structures, but the cancer has not spread to the lymph nodes or elsewhere.
    • Stage IIIB: The tumor is any size, and the cancer has spread to regional lymph nodes.
  • Stage IV: There is distant metastasis.

Pancreatic NET Staging

For a NET of the pancreas, there are 4 stages, I through IV (1 through 4). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments. 

  • Stage I: There is a small tumor in the pancreas and it has not spread elsewhere in the body. 
  • Stage II: The tumor is larger and has not spread to the regional lymph nodes or elsewhere in the body.
  • Stage III: The tumor is any size and has spread to the regional lymph nodes. Or, the tumor has spread to the stomach, spleen, colon, or adrenal gland, or the wall of the celiac axis or the superior mesenteric artery, but the cancer has not spread to the regional lymph nodes or anywhere else.
  • Stage IV: There is distant metastasis.