Islet cell carcinoma is a type of cancer in which tumors form in the pancreas. The pancreas is a hormone-producing gland that rests behind the stomach and in front of the spine.
The hormone-producing cells of the pancreas cluster together in small groups, called islets, throughout the pancreas. When a tumor occurs in one of these clusters, it’s called islet cell carcinoma. The disease is also sometimes called a pancreatic endocrine tumor, a pancreatic neuroendocrine tumor, or a pancreatic carcinoid.
Islet cell carcinoma is a fairly rare cancer. Doctors aren’t exactly sure why people develop islet cell carcinoma. One strong risk factor for the disease is a rare genetic disorder known as multiple endocrine neoplasia type 1 syndrome (MEN1 syndrome). This disorder causes tumors within the pancreas that are usually benign (not cancer), but sometimes become malignant (cancer). It can also cause a problem with the parathyroid gland, which may result in kidney stones, tumors of the pituitary gland, and severe stomach ulcers.
Islet cell carcinomas are classified into several types:
Gastrinoma. Gastrin is a hormone that aids the digestion of food. When a tumor forms in gastrin-producing cells, it is known as gastrinoma.
Insulinoma. Insulin controls the amount of sugar, or glucose, in the bloodstream. When a tumor occurs in this group of cells, it is an insulinoma.
Glucagonoma. Glucagon also plays a role in the amount of glucose in the bloodstream, and in this case, it increases the amount of glucose present. A gluconoma occurs when a tumor arises among a group of glucagon producing cells.
Others. Other types of islet cell tumors produce hormones that control the balance of water, sugar, and salt in your body. These include VIPomas, which affect vasoactive intestinal peptides, and somatostatinomas, which affect somatostatin. These types of islet cell tumors are often grouped together because they are treated in much the same way.
Specific symptoms of islet cell carcinomas are different, depending on what type you have. Some islet cell carcinomas affect nonfunctioning cells, which don't produce hormones and don’t cause symptoms for a long time. Ultimately, they may lead to some symptoms in the body because their growth puts pressure on other organs, like the bile ducts. Other islet cell carcinomas cause symptoms because of the overproduction of hormones. Here is the breakdown of symptoms that you may experience:
Nonfunctioning islet cell carcinoma:
Yellowing on the skin or whites of the eyes (jaundice)
Diarrhea and indigestion
Pain or a lump in the abdomen or back
Pain in the abdomen (belly) or back
Fatigue (extreme tiredness)
Skin rash or dry skin
Feeling tired or dizzy
Blood clots in the lungs
Abdominal cramps or pain
Symptoms related to low potassium levels—muscle weakness, aches, cramps, numbness, tingling, frequent urination, confusion, thirst, and rapid heartbeat
Diarrhea or other strange bowel movements
Yellowing of the skin or eyes
Unexplained weight loss
High blood sugar symptoms—weakness, hunger, confusion, headaches, frequent urination, and dry skin
If you have any of these symptoms and your doctor thinks that you might have islet cell carcinoma, he or she will use a host of tests to find out for certain. This process starts with a physical exam and a full medical history. Next, a number of blood tests and other laboratory tests can yield further clues by looking for markers of the disease in the blood.
A number of advanced scanning techniques can also be used to look for the tumor within the pancreas. These include CT scans, MRI scans, and ultrasound. In some instances, your doctor may perform a biopsy, which is a surgery that removes cells so they can be checked under a microscope to look for cancer.
Islet cell carcinomas can often be cured. The treatment varies based on the type of islet cell carcinoma that you have. As a general rule, however, surgical removal of the tumor is the primary course of treatment whenever it’s possible.
For tumors that can’t be removed by surgery, or that have spread to other parts of the body, treatments such as chemotherapy, hormone therapy, radiofrequency ablation, and cryosurgical ablation (freezing) are often used to shrink the tumor or destroy it.
Experts don’t know how to prevent islet cell carcinoma. The best thing you can do is be aware of your health, and contact your doctor if you experience any of the symptoms listed above, especially in combination. People with MEN1 syndrome should be especially vigilant, as they have a greater risk of developing the disease.
In addition to the treatments for the specific cancers, your doctor should also provide you with some options for managing the symptoms that come along with islet cell carcinoma. This can include drug therapy to manage stomach ulcers, therapy or over-the-counter remedies to deal with diarrhea, or drugs or other strategies to keep your blood sugar in check.