What is Pancreatic NET?

Medically Reviewed on 12/16/2022
Pancreatic NET
Some pancreatic NETs develop in cells that are nonfunctional and don't produce hormones, which means they don't show signs right away.

Pancreatic neuroendocrine tumors (pancreatic NETs or PNETs) or islet cell tumors account for less than two percent of all cases of pancreatic cancer.

  • They may be benign or malignant and have a slower growth rate than exocrine tumors. 
  • They originate from islet cells, endocrine (hormone-producing) cells in the pancreas, which grow abnormally.

Some PNETs continue to release hormones; these tumors are referred to as functional tumors because they induce your body to produce an excessive amount of the targeted hormone. Gastrinoma and glucagonoma are two examples.

Most of the time, nonfunctional tumors do not produce a large number of hormones.

What are the types of pancreatic neuroendocrine tumors?

Insulinomas are the most prevalent type of functional pancreatic neuroendocrine tumor (PNET). Most pancreatic endocrine tumors are insulinomas, which produce hormones when they are active.

Five other types of PNETs are as follows:

  1. Glucagonomas: Develop from the cells that produce glucagon, a hormone that increases blood sugar levels.
  2. Gastrinomas: Develop from the cells that produce gastrin, the hormone that instructs your body to produce stomach acid.
  3. VIPomas: Develop from the cells that produce vasoactive intestinal peptide, a substance that controls the movement of specific chemicals through your small intestine.
  4. Somatostatinomas: Somatostatin-producing cells give rise to these tumors. Somatostatin helps control glucagon and insulin levels.
  5. Adrenocorticotropic hormone (ACTH)-secreting tumors: Formed by cells that produce ACTH.

What are the symptoms of pancreatic neuroendocrine tumors?

Depending on the type of tumor, you may experience distinct pancreatic neuroendocrine tumor (PNET) symptoms. Some PNETs develop in nonfunctional cells. These don't produce hormones and don't show signs right away. They eventually impose pressure on other organs, such as the bile ducts, which may produce various symptoms in the body. Other PNETs produce too many hormones, resulting in symptoms.

Here are the symptoms associated with the following types of PNETs:


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What are the stages of pancreatic neuroendocrine tumors?

The most popular staging method used for staging pancreatic neuroendocrine tumors (PNETs) is the American Joint Committee on Cancer (AJCC) TNM system.

Table 1. Four stages of PNETs and their characteristics
AJCC staging Stage grouping Stage description
Stage I




The tumor is less than 2 cm in diameter and is still contained within the pancreas (T1). Cancer has neither spread to adjacent lymph nodes (N0) nor spread to other parts of the body (M0).
Stage II




The tumor’s diameter is at least 2 cm but does not exceed 4 cm and has not spread outside the pancreas (T2).

Cancer has neither spread to adjacent lymph nodes (N0) nor spread to distant organs(M0).




The tumor is larger than 4 cm in diameter and is still in the pancreas, or the tumor has spread to the duodenum or the common bile duct (T3). Cancer has neither spread to adjacent lymph nodes (N0) nor spread to other parts of the body (M0).
Stage III




The tumor has spread to the stomach, colon, spleen, adrenal gland, or large blood vessels (T4). Cancer has neither spread to adjacent lymph nodes (N0) nor spread to other parts of the body (M0).

Any T



The tumor can be of any size and may or may not have spread outside the pancreas (any T). It has spread to the lymph nodes (N1) but not to other organs of the body (M0).
Stage IV

Any T

Any N


The tumor may or may not have grown outside of the pancreas, and it can be of any size (any T). It could or may not have spread to nearby lymph nodes (any N). Cancer has spread to other parts of the body (M1).

How are pancreatic neuroendocrine tumors treated?

People with pancreatic neuroendocrine tumor (PNET) might get various treatments, such as:

  • Surgery: The tumor may be removed surgically. Any of the following surgical procedures could be used:
    • Enucleation: A surgical procedure that solely removes the tumor. This is used when pancreatic cancer affects only one area.
    • Pancreatoduodenectomy: A surgical procedure in which the pancreatic head, the gallbladder, adjacent lymph nodes, and a portion of the stomach, small intestine, and bile duct are removed. The pancreas still has enough tissue to produce insulin and digest acids. The organs that are removed during this treatment depend on the person’s health. This process is also known as the Whipple method. The chances of long-term survival with pancreatic cancer are increased after a Whipple procedure.
    • Distal pancreatectomy: Removes the body and tail of the pancreas. In addition, the spleen too may be removed if cancer has spread to this organ. 
    • Total gastrectomy: Removes the entire stomach.
    • Parietal cell vagotomy: This surgery removes the nerve that triggers acid production by stomach cells.
    • Liver resection: A surgery that removes the liver partially or completely.
    • Cryosurgical ablation: A process in which aberrant cells are removed from tissue by freezing it. Liquid nitrogen or liquid carbon dioxide is typically used in a specialized device. The device may be implanted through the skin or used during a laparoscopy or surgery. Cryoablation is another name for this process.
    • Radiofrequency ablation: A unique probe with small electrodes is used in radiofrequency ablation to eliminate cancer cells. Sometimes only local anesthetic is required because the probe can be inserted directly through the skin. In other instances, an abdominal incision is made to place the probe.
  • Chemotherapy: A type of cancer treatment that uses medications to kill or prevent the division of cancer cells to stop the spread of the disease. When administered orally, intravenously, or intramuscularly, chemotherapy medications can reach cancer cells throughout the body. Direct injection of chemotherapy into the cerebrospinal fluid, an organ, or a body cavity, such as the abdomen, causes the medications to primarily target cancer cells in those regions (regional chemotherapy). The use of multiple anticancer drugs is known as combination chemotherapy. Chemotherapy is administered differently depending on the type of cancer being treated.
  • Hormone therapy: Hormone treatment removes or hinders the action of specific hormones to prevent the proliferation of cancer cells. Hormones are created by glands in the body and then released into circulation. Some hormones may cause certain tumors to enlarge. If tests show that the cancer cells have receptors where hormones can bind, the synthesis of hormones is suppressed or their activity is stopped using drugs, surgery, or radiation therapy.
  • Targeted therapy: Targeted therapy is medical care that isolates and destroys cancer cells using medicines or other substances. Compared with chemotherapy and radiation therapy, targeted therapies typically don't kill healthy cells. Treatment of PNETs with specific targeted treatments is currently under investigation.
  • Hepatic arterial occlusion or chemoembolization: The practice of stopping or reducing blood flow from the hepatic artery (the major blood vessel that carries blood to the liver) to the liver using drugs, minute particles, or other substances. The intention is to stop the development of malignant liver cells. The tumor is deprived of the oxygen and nutrition needed to flourish. The hepatic portal vein, which takes blood from the stomach and intestine, continues to provide blood to the liver.
Medically Reviewed on 12/16/2022
Image Source: iStock image