This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science at CTCA.
This page was updated on June 6, 2022.
Identifying the stage of disease is an important step in planning the appropriate treatment for neuroendocrine tumors. NETs may:
Because NETs can be found in different areas of your body, different staging systems are used depending on its location. You also may hear grading discussed as well. Grade is a different measure from stage, but they both tell your care team more about your cancer and which treatment may be most successful.
The American Joint Committee on Cancer (AJCC) has created the staging systems most commonly used for NETs. Generally, lower stages are associated with better survival rates for all types of NETs. The stage of your cancer provides a useful common language for you and your care team as you discuss the diagnosis and treatment options. Your care team may use your stage as a foundation to guide which treatment options may be most appropriate for you, based on your overall health and preferences as well.
The TNM system is often used as a way to describe different attributes of a cancer, and it’s used for all types of NETs.
After T, N and M, doctors will add a number or letter providing greater detail, such as T0 or N1—with higher numbers indicating more advanced levels of cancer progression.
Stage 1: Cancer is found in the pancreas and hasn’t spread. The tumor size is smaller than 2 cm wide.
Stage 2: The tumor is still only in the pancreas, but it is greater than 2 cm wide. It hasn’t yet spread to nearby lymph nodes or distant body parts, but it may have grown into the bile duct that carries digestive fluid through the pancreas to the small intestine, or into the upper part of the small intestine.
Stage 3: The tumor may or may not have spread to nearby lymph nodes, but it hasn’t yet spread to distant parts of the body. Or, it may or may not have begun to grow outside the pancreas into blood vessels or nearby organs.
Stage 4: The cancer has spread to distant parts of the body.
NETs of the gastrointestinal tract may begin in the stomach, small intestine, appendix, colon or rectum. The staging for each of these is slightly different, but they all have stages 1 through 4, with higher stages representing more advanced cancer that may be more difficult to treat. Some may have substages that provide even more description of where the cancer cells are found.
Stage 1: The tumor is 1 cm wide or smaller and has grown deeper than where it started. It hasn’t spread to any lymph nodes or distant parts of the body.
Stage 2: The tumor is larger than 1 cm across or has grown into other layers of tissue, possibly including the main muscular layer of the stomach (the muscularis propria).
Stage 3: The tumor has grown into the outermost covering of the stomach or into nearby structures or organs. It may have spread to lymph nodes but not to distant parts of the body.
Stage 4: The cancer has spread to distant parts of the body.
Stage 1: The tumor is 1 cm wide or smaller and hasn’t spread to lymph nodes or beyond the small intestine.
Stage 2: The tumor is larger than 1 cm across and has begun to grow into other layers of the small intestine, possibly including the main muscular layer (the muscularis propria). It hasn’t spread to lymph nodes or distant body parts.
Stage 3: The tumor has grown and is affecting nearby organs, other structures or the outermost covering of the small intestine (the serosa or visceral peritoneum). It may have spread to nearby lymph nodes but hasn’t metastasized to other parts of the body.
Stage 4: The cancer has spread to distant parts of the body.
Stage 1: The tumor is 2 cm wide or smaller and hasn’t spread to any lymph nodes.
Stage 2: The tumor is wider than 2 cm and may or may not be growing into other layers of tissue around the appendix. It hasn’t spread to any lymph nodes or distant parts of the body.
Stage 3: The tumor still hasn’t metastasized to distant parts of the body, but it may have spread to nearby lymph nodes. Or, it may be growing into the outermost tissue layer of the appendix or nearby structures or organs.
Stage 4: The cancer has spread to distant parts of the body.
Stage 1: The tumor is no more than 2 cm across and has grown into deeper layers of cells, affecting the lamina propria or submucosa. The cancer hasn’t spread to nearby lymph nodes or distant parts of the body.
Stage 2A: The tumor is greater than 2 cm wide and has grown into other tissue layers of the colon or rectum.
Stage 2B: The tumor has grown into one of the most outermost layers of the colon or rectum but hasn’t spread to nearby lymph nodes.
Stage 3A: The tumor hasn’t yet spread to nearby lymph nodes but has grown into the outermost covering of the intestine or into its nearby organs or structures.
Stage 3B: The tumor has spread to nearby lymph nodes, but it hasn’t metastasized to distant parts of the body.
Stage 4: The cancer has spread to distant parts of the body.
Staging for NETs of the lung follows the staging for the most common type of lung cancer, non-small cell lung cancer (NSCLC).
Stage 0: Also called “in situ,” a stage 0 lung NET hasn’t grown into any nearby tissues or spread—it remains in the same place it started.
Stage 1: A stage 1 NET is a small tumor that hasn’t affected any nearby lymph nodes.
Stage 2: Stage 2 lung NETs are larger than stage 1 tumors, and they may or may not have spread to nearby lymph nodes.
Stage 3: These lung NETs may have spread to the lymph nodes but not to distant parts of the body. They haven’t entered the bloodstream or affected other organs. These NETs are further designated as stage 3A, 3B or 3C depending on the specific lymph nodes the cancer is found in and the exact size of the tumor. Stage 3 NETs are difficult to fully remove with surgery, especially if they’re growing into or near other structures, such as the heart or blood vessels.
Stage 4: Advanced-stage lung NETs have spread to the other lung or distant parts of the body, such as the brain or liver. Stage 4 NETs aren’t typically treated with surgery because it’s unlikely to remove all the cancer.
NETs may recur after treatment, even several years later, regardless of where it started. Because of this, staying on top of follow-up care is essential. Your cancer care team may continue to monitor you, perform imaging tests and ask you to keep an eye out for any symptoms that may be caused by a recurrent NET.
More than 50 percent of NETs have already spread to other parts of the body by the time they are diagnosed. NETs metastasize most often to the liver, peritoneal cavity or bone.
Neuroendocrine tumors are staged according to the TNM staging system: tumor (T), node (N), metastasis (M). The World Health Organization (WHO) classifies neuroendocrine tumors according to the malignant potential of the tumor:
Staging is a process. Your cancer care team works to make sure they have all the information they need before determining a stage. That may mean more tests or scans and waiting for the results.
Once a stage is determined, your care team may discuss your treatment options and your prognosis—your chance of recovery—with you. There are different survival rates for different stages of cancer, but keep in mind that those rates aren’t a prediction about how your treatment may go.
As you discuss your options with your team, ask any questions that will help in making your decision. Your care team may work with you to find the appropriate plan, including one that treats symptoms from the tumor or side effects from treatments.