Neuroendocrine Tumors (NETs), from the CureRays guide library.

Neuroendocrine tumors grow from the body's hormone-producing cells and often grow slowly; many are highly treatable, and a special form of targeted radiation can find and treat them throughout the body.

What it is.

Neuroendocrine tumors, or NETs, grow from neuroendocrine cells — specialized cells scattered throughout the body that act like a bridge between the nervous system and the hormone (endocrine) system. These cells release hormones that help control body functions, and they're found in many places, especially the digestive tract and the lungs. NETs are a diverse family: some are tiny and slow-growing and may never cause trouble, while others grow faster and behave more like typical cancers. A key feature is that some NETs make extra hormones that cause specific symptoms — for example flushing, diarrhea, or wheezing in a condition called carcinoid syndrome — while others, called non-functional, cause no hormone symptoms at all. Because many NETs grow slowly and carry special targets on their surface, they have unique treatment options, including a remarkable form of targeted radiation that travels through the bloodstream to find tumor cells anywhere in the body.

How radiation treats it.

Radiation treats neuroendocrine tumors in two complementary ways. The first, external-beam radiation, uses focused high-energy x-rays from a machine to damage the DNA of tumor cells in a defined area so they stop growing — useful for a tumor that can't be removed or a painful deposit. The second is special to NETs: peptide receptor radionuclide therapy, or PRRT. Because most neuroendocrine cells carry a particular receptor on their surface, doctors can attach a radioactive atom to a molecule that seeks out that receptor, infuse it into the bloodstream, and let it travel through the body to deliver radiation directly to tumor cells wherever they hide — even tiny deposits scattered in the liver or bones. This 'theranostic' approach means the same targeting can be used first to image the tumors and then to treat them. Treatments are generally well tolerated; PRRT is given as a series of infusions, and side effects such as temporary fatigue or mild nausea are usually manageable.

The ways we can treat it.

Peptide receptor radionuclide therapy (PRRT). A radioactive atom is attached to a molecule that locks onto receptors found on most NET cells. Given by infusion, it circulates through the body, sticks to tumor cells wherever they are, and delivers radiation precisely to them while largely sparing healthy tissue.

External-beam radiation. Focused radiation from outside the body can treat a NET that can't be removed or relieve symptoms from a specific deposit, such as one pressing on bone or causing pain.

Stereotactic radiation (SBRT). Very precise, high-dose radiation in a few sessions can control a limited number of spots — for example in bone or the liver — while protecting nearby organs.

Questions we hear often.

Are all neuroendocrine tumors cancer? Most NETs are considered cancers, but many — especially low-grade ones — grow so slowly that they behave more like a chronic condition than an aggressive cancer. Some tiny NETs found by chance may never cause problems. The grade and stage together tell your team how concerned to be and how actively to treat.

What is PRRT, in simple terms? PRRT is a targeted radiation treatment given through a vein. A radioactive particle is attached to a molecule that latches onto neuroendocrine tumor cells, so the radiation is carried straight to the tumors throughout the body and delivered from the inside, sparing most healthy tissue. It's a powerful option for NETs that have spread.

Can neuroendocrine tumors be cured? Localized NETs are often cured by surgery. When they've spread, many — particularly low-grade tumors — can still be controlled for many years with somatostatin injections, PRRT, and other therapies, allowing people to live well for a long time.

This guide is informational only. It is not medical advice — please confirm anything here with your care team.