What Are Lung NETs?
Lung neuroendocrine tumors (NETs) are rare tumors that form from neuroendocrine cells within the lungs. Neuroendocrine cells can be found in other organs throughout the body, but lung NETs come from the ones located inside the lungs. They can grow slowly or quickly depending on the type. There are four main types of lung NETs (Typical Carcinoid, Atypical Carcinoid, Large Cell Neuroendocrine Carcinoma, and Small Cell Lung Carcinoma). Types of lung NETs are grouped by how the cells look under the microscope and how fast they grow. They're different from other lung cancers, may not cause symptoms early on, and require personalized diagnosis, treatment, and long-term monitoring.
Quick Facts:
- Lung NETs are rare, making up only 1–2% of all lung cancers.
- NETs develop more often in the digestive tract than in the lungs. Only about 1 out of 5 NETs start in the lungs.
- They can be noncancerous or cancerous and grow at different speeds.
- Symptoms may not appear until later stages.
- Surgery is a common treatment, though options vary based on the tumor type and stage.
How Lung NETs Form
Your lungs contain many different types of cells. These cells have different jobs like controlling breathing or keeping germs out. One type of cell in your lungs (and throughout your body) is called a neuroendocrine cell. These cells are similar to both nerve cells and hormone-producing cells. In the lungs, these cells respond to signals from the body to help with lung function.
Sometimes these cells can grow uncontrollably and turn into a tumor in the lungs called a neuroendocrine tumor (NET). Not all NETs are cancerous. Cancerous NETs are sometimes called neuroendocrine neoplasms or neuroendocrine carcinomas. Because NET cells are throughout the body, this can happen places other than the lung. The digestive tract is the most frequent location for NETs, while the lung is the second most common.
What Causes Lung NETs?
Researchers are still trying to understand what causes NETs in the lungs. In some cases, tobacco use may increase your risk of developing lung NETs. Another risk factor may be a rare genetic disorder called Multiple Endocrine Neoplasia Type 1 (MEN1). In most cases, it is unclear what has caused a person to develop NETs.
A rare non-cancerous condition called DIPNECH (Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia) can turn into NETs. Treatment options for DIPNECH vary based on the type of NET and its characteristics.
Lung NETs often affect people in their 60s, and they are slightly more common in females.
Types of Lung NETS
There are four different types of lung NETs. They are named for how the cells look under the microscope. Below is an overview of the subtypes of lung NETs.
| Type of NET | Location | Grade (how quickly the cells are dividing) | Growth Speed | Does it typically spread? | Associated with Tobacco Use |
|---|---|---|---|---|---|
Typical Carcinoid (TC) | The center of the chest (central) | 1 (Low) | Slow | No | No |
Atypical Carcinoid (AC) | Towards the edge of the lung (peripheral) | 2 (Intermediate) | Slightly faster, but still slow | A little more likely to spread than TC | No |
Large Cell Neuroendocrine Carcinoma (LCNEC) | Can be central or peripheral | 3 (High) | Fast growing | Likely to spread | Yes |
A form of small cell lung cancer (SCLC) | Originates in the central bronchi (large tubes that carry air from your windpipe to your lungs) but often spreads | 3 (High) | Fastest growing | Likely to spread | Yes |
Learn more about the characteristics of lung NETs and how they impact treatment.
Symptoms of Lung NETs
Symptoms are often related to the characteristics of the tumor(s) like size, location and functionality (whether the tumor is releasing hormones into the bloodstream). Some NETs do not cause any symptoms until they are at a later stage, which makes early detection and treatment more challenging.
Be sure to speak with your physician if you are experiencing any concerning symptoms.
Diagnosis of Lung NETs
Lung NETs are usually found on a CT scan, either after a person has breathing symptoms or “incidentally” (when looking for something else). The CT scan is followed by a biopsy, where physicians remove a sample from the tumor to confirm the makeup of the tumor. You may receive other procedures and blood tests to learn more about your exact cancer.
Treatment of Lung NETs
Treatment for lung NETs is based on the unique characteristics of your tumor. This includes the type, grade, stage and location. Treatment also depends on your overall health and any other health conditions you may have. It is important to work closely with a physician who is up to date on the treatment of lung NETs, as there are new and emerging treatments being studied. In some cases, a physician might recommend “watchful waiting” if the tumor appears slow growing. Below is an overview of the types of treatment typically used to treat lung NETs. Not every treatment option is the right choice for every patient. Your physician can help you understand your options and what to expect.
Living with Lung NETs
Monitoring Lung NETs
It is important to monitor most patients with lung NETs for disease growth or spread. Patients who are not candidates for surgery will receive scans as needed so physicians can monitor how well the cancer is responding to treatment.
Patients with earlier stage disease who get surgery (with the intent to cure the disease) may receive chest and abdomen CT scans every six months for the first two years and then yearly for at least 10 years. Low-grade (typical) lung NETs that do not involve the lymph nodes are unlikely to come back, so those patients are unlikely to receive regular scans after surgery to look for new nodules. Talk with your physician about what you can expect during and after treatment.
Challenges for Patients with Lung NETs
Patients with lung NETs face some unique challenges. Lung NETs account for only 1 to 2 percent of all cancers in the lung. Because lung NETs can be rare, researchers are still working to try and find the best way to detect, treat and follow-up with these cancers. As researchers work to identify best practices, there can be confusion and discrepancies about how to best treat lung NETs. It is important to work with a care team who are up to date on the latest research.
Another challenge is misdiagnosis. The symptoms of lung NETs can be similar to a variety of other diseases which causes delayed and mis-diagnoses.
Patients with lung NETs may also struggle with stigma and isolation. Lung cancer resources are usually focused on non-small and small-cell lung cancer and patients with lung NETs may feel excluded from support offerings, or may find it challenging to find other patients in their shoes. Also, because of lung cancer’s connection to tobacco use, it is not uncommon for some patients to feel embarrassed or ashamed if they used tobacco. Patients may feel frustrated and stigmatized when they share they have a cancer of the lungs, as much of the public’s first question after hearing about a lung cancer diagnosis is “Did you smoke?”
Lung cancer research can move at a rapid pace. Always speak with your doctor about the most up-to-date treatment guidelines.
Page last updated: May 20, 2026
