This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on July 20, 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 the body, different staging systems are used depending on its location. Grading may be discussed as well. Grade is a different measure from stage, but they both tell the care team more about the cancer and which neuroendocrine cancer 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 cancer provides a useful common language for the patient and his or her care team as diagnosis and treatment options are discussed. The care team may use the cancer's stage as a foundation to guide which treatment options are most appropriate for each patient, based on his or her overall health and preferences as well.
The TNM system is often used to describe different attributes of a cancer, and it’s used for all types of NETs.
T (tumor): This describes the size of the original tumor.
N (node): This indicates whether the cancer is present in the lymph nodes.
M (metastasis): This refers to whether cancer has spread (metastasized) to other parts of the body.
After T, N and M, doctors add a number or letter providing greater detail, such as T0 or N1—with higher numbers indicating more advanced levels of cancer progression. Once the individual T, N and M scores have been established, an overall stage is assigned.
Because the stages of NETs depend on where the cancer is located, the staging systems for individual types of neuroendocrine tumors are listed below.
Cancer is found in the pancreas and hasn’t spread. The tumor size is smaller than 2 centimeters (cm) wide.
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.
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.
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.
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.
The tumor is larger than 1 cm or has grown into other layers of tissue, possibly including the main muscular layer of the stomach (the muscularis propria).
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.
The cancer has spread to distant parts of the body.
The tumor is 1 cm wide or smaller and hasn’t spread to lymph nodes or beyond the small intestine.
The tumor is larger than 1 cm 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.
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.
The cancer has spread to distant parts of the body.
The tumor is 2 cm wide or smaller and hasn’t spread to any lymph nodes.
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.
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.
The cancer has spread to distant parts of the body.
The tumor is no more than 2 cm wide 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.
The tumor is greater than 2 cm and has grown into other tissue layers of the colon or rectum.
The tumor has grown into one of the most outermost layers of the colon or rectum but hasn’t spread to nearby lymph nodes.
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.
The tumor has spread to nearby lymph nodes, but it hasn’t metastasized to distant parts of the body.
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).
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.
A stage 1 NET is a small tumor that hasn’t affected any nearby lymph nodes.
Stage 1A: The tumor measures 3 cm or smaller. Substages 1A1, 1A2 or 1A3 may be used to describe the tumor’s size in greater detail.
Stage 1B: The tumor measures between 3 cm and 4 cm wide.
Stage 2 lung NETs are larger than stage 1 tumors, and they may or may not have spread to nearby lymph nodes.
Stage 2A: The tumor hasn’t spread to lymph nodes and measures between 4 cm and 5 cm.
Stage 2B: Either the tumor is 5 cm or smaller and has spread to nearby lymph nodes, or it’s larger than 5 cm but hasn’t spread to the lymph nodes.
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.
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.
Stage 4A: The cancer has spread but remains within the chest—to the tissue surrounding the heart or lung, or to the other lung. Stage 4A can also include cancer that has spread to only one area outside of the chest.
Stage 4B: The cancer has spread outside of the chest and lungs to one or more organs.
NETs may recur after treatment, even years later, regardless of where they started. Because of this, staying on top of follow-up care is essential. The cancer care team may continue to monitor the patient, perform imaging tests and ask him or her to keep an eye out for any symptoms that may be caused by a recurrent NET.
More than 20 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.
Recurrent neuroendocrine tumors are graded based on the World Health Organization (WHO) classifications, which are made according to the malignant potential of the tumor:
Identifying the stage of cancer not only helps the care team determine a treatment plan, it also helps predict a potential prognosis. This is achieved by calculating the percentage of people with neuroendocrine tumors who survive five years or more after diagnosis compared to people who don’t have that type of cancer. It’s important to remember that this is only a statistic based on all people with NETs several years in the past, so individual patient experiences may vary.
Five-year relative survival rates differ depending on the type and stage of neuroendocrine tumors. Below are the available five-year relative survival rates.
Pancreatic neuroendocrine tumors: According to the American Cancer Society, the overall five-year relative survival rate is 53 percent. For pancreatic NETs contained to the pancreas, the five-year relative survival rate is 95 percent. If the cancer has grown into nearby tissues or lymph nodes, the five-year relative survival rate is 72 percent. For pancreatic NETs that have spread to distant body parts, the five-year relative survival rate is 23 percent.
Gastrointestinal neuroendocrine tumors: According to the American Society of Clinical Oncology, (ASCO) the overall five-year relative survival rate for NETs in the GI tract is 94 percent. For GI NETs that have not spread beyond the area of origin, the five-year relative survival rate is 97 percent. If the cancer has grown into nearby tissues or lymph nodes, the five-year relative survival rate is 96 percent. If the NET has spread to distant body parts, the five-year relative survival rate is 68 percent.
Neuroendocrine tumors of the lung: According to data from ASCO, the overall five-year relative survival rate for NETs in the lung is 89 percent. If the cancer has not spread beyond the area of origin, the five-year relative survival rate is 98 percent. If the cancer has grown into nearby tissues or lymph nodes, the five-year relative survival rate is 86 percent. If the cancer cells have spread to distant body parts, the five-year relative survival rate is 55 percent.
All neuroendocrine tumors: According to the Surveillance Epidemiology and Ends Results (SEER) database, the five-year survival rate for all neuroendocrine tumors is 39.4 percent.
Keep in mind that the survival rate for neuroendocrine tumors depends on a variety of factors, including the patient’s age, overall health and the extent of the disease, so always talk to the care team about the patient’s individual prognosis.
Next topic: How are neuroendocrine tumors diagnosed?