Most lung cancers develop in the cells that line the lungs’ airways. However, lung neuroendocrine tumors (NETs) — also called “lung carcinoid tumors” — are rare cancers that form from hormone-producing cells. People with lung NETs may experience different symptoms compared to those with other types of lung cancer. They also need different treatments to target hormones.

In this article, we’ll discuss six facts about NETs affecting the lungs and how they’re treated. We’ll also cover how NETs affect your prognosis (outlook) compared to other lung cancers. To learn more about NETs and your specific diagnosis, talk to your doctor or oncologist (cancer specialist).

1. NETs Form From Hormone-Producing Cells

Lung neuroendocrine tumors develop from neuroendocrine cells. Neuroendocrine cells act like nerve cells and hormone-producing cells. They communicate by sending and receiving hormones (chemical messengers) to one another.

Most NETs form in the gastrointestinal tract, affecting the intestines, stomach, and colon. However, between 20 percent and 30 percent of these tumors form in the lungs or bronchi (airways). Lung NETs can form anywhere in the lungs and airways.

2. NETs of the Lung Are Very Rare

Overall, the risk of developing a NET tumor of the lung is very low. These tumors are rare, accounting for only 1 percent to 2 percent of all lung cancer cases. Around 2,000 to 4,500 people are diagnosed with a lung NET in the United States annually.

You may be more likely to develop a lung NET if you have certain risk factors. One risk factor is having a family history of multiple endocrine neoplasia type 1 (MEN1). This condition is passed down from parents to their children.

Lung NETs are also more likely to develop in white people and people aged 45 to 55, according to the American Cancer Society. These tumors rarely develop in children.

3. There Are Several Types of Lung NETs

Lung NETs can be broken down into several types.

The majority of NETs affecting the lungs are considered small cell lung cancer (SCLC). You may also hear your oncologist use the terms “lung neuroendocrine carcinoma” or “large cell neuroendocrine carcinoma.”

The other 2 percent are known as atypical and typical endocrine tumors. Typical NETs are slow-growing tumors that rarely metastasize (spread) to other parts of the body. Atypical endocrine tumors are more aggressive than typical NETs. This means they grow faster and are more likely to spread to other organs. SCLCs are the most aggressive NETs.

Functional vs. Nonfunctional NETs

Doctors also divide NETs by whether they make any hormonelike substances. These include amines and neuropeptides. If your NET makes these substances, it’s considered a “functional NET.” If the tumor makes very little or no amines or peptides, it’s known as a “nonfunctional NET.”

Your oncologist will want to determine whether your NET is functional or nonfunctional. Tumors that make these hormonal substances raise your risk of certain symptoms.

4. Lung NETs Cause Similar Symptoms to Other Lung Cancers

Like other lung cancers, NETs can block the airways and make it harder to breathe. Common symptoms of a lung NET include:

• Shortness of breath
• Chest pain
• Coughing or wheezing
• Coughing up blood
• Pneumonia that keeps returning after treatment

People with lung NETs are also more likely to develop carcinoid syndrome. This complication occurs when a tumor releases chemicals into the bloodstream. Symptoms of carcinoid syndrome include:

• Skin flushing on the chest, neck, and face
• Wheezing
• Diarrhea
• Rapid heartbeat

If you’re experiencing any lung NET symptoms, talk to your doctor. They can run tests to check your lung function and look for a tumor. Examples include:

• Imaging tests like a chest X-ray or computed tomography (CT) scan
• A bronchoscopy to look inside your lungs
• A biopsy to take tissue samples from a tumor during a bronchoscopy

4. People With Lung NETs Can Develop Hormonal Complications

Functional lung NETs release hormones, which can lead to complications. Studies show that 1 percent to 2 percent of lung NETs are associated with Cushing’s syndrome. This hormonal condition develops when a tumor makes too much adrenocorticotropic hormone (ACTH). Too much ACTH causes high cortisol levels.

Symptoms of Cushing’s syndrome include:

• High blood pressure
• Diabetes
• Fat buildup between the shoulders, forming a “buffalo hump”
• Weakness and fatigue
• Rounded face, known as “moon face”
• Excess hair growth on the face, chest, abdomen, and thighs
• Vision changes

5. Doctors Treat Neuroendocrine Tumors of the Lung

Your lung NET treatment plan depends on the size and spread (stage) of your tumor, along with your overall health. You’ll work together with your oncologist to weigh the best treatment options for your specific case.

Surgery

If possible, your oncologist will likely first recommend removing the entire tumor. Smaller tumors that haven’t spread much are usually treated and cured with surgery alone. Your surgeon may also take nearby lymph nodes (immune system structures) to check for cancer spread.

The exact surgical procedure depends on where your tumor is located. A lobectomy is the most common procedure for lung NETs, which removes the entire lung lobe. The right lung has three lobes, and the left lung has two.

Targeted Therapies

Targeted therapies “target” and block specific proteins made by cancer cells. The U.S. Food and Drug Administration (FDA) has only approved one treatment for lung NETs. Your oncologist may prescribe everolimus (Afinitor) to slow down lung NET growth. This medication blocks proteins that cancer cells need to grow and make new blood vessels. Everolimus can help treat an advanced lung NET, but it likely won’t shrink it.

Somatostatin analogs work by blocking the hormone somatostatin. Normally, somatostatin controls how the body releases other hormones. It can also stop NETs from releasing hormonelike substances. Small studies show that lanreotide (Somatuline Depot) and octreotide (Sandostatin) can help treat lung NETs.

It’s important to note that the FDA hasn’t approved any somatostatin analogs for lung NETs. However, doctors can prescribe them “off-label” — that is, or outside of their approved use — since they’re also used to treat other NETs.

Radiation Therapy

Oncologists may also use radiation therapy to shrink lung NETs. This treatment is usually given to relieve pain and uncomfortable symptoms of cancer spread to other organs. Radiation therapy can also shrink tumors, making it easier to remove them with surgery.

Chemotherapy

Chemotherapy is a key part of most lung cancer treatments. However, it’s only used to treat lung NETs if:

• They’re causing severe pain and discomfort.
• They’ve spread to other parts of the body.
• They’re growing very quickly.

Your oncologist will let you know if they think chemotherapy is right for you.

6. The Overall Prognosis With Lung NETs Is Good

When doctors and researchers talk about a person’s chance of recovering from lung NETs, they use relative survival rate. This statistic breaks down how many people with a lung NET are likely to survive a certain amount of time after their diagnosis or start of treatment. The rate is compared to people in the general population without a lung NET.

The overall five-year relative survival rate with lung NETs is 89 percent. This means that five years after diagnosis, a person with a lung NET is 89 percent as likely to be alive compared to the general population.

Researchers have also broken down five-year relative survival rates based on lung NET stages. They are:

• Localized disease (early-stage cancer that hasn’t spread) — 98 percent
• Regional disease (cancer that has spread to nearby lymph nodes or tissues) — 86 percent
• Distant disease (cancer that has metastasized) — 55 percent

For comparison, the relative five-year survival rate for all lung cancers is 26.6 percent.

Talk With Others Who Understand

MyLungCancerTeam is the social network for people with lung cancer and their loved ones. On MyLungCancerTeam, more than 13,000 members come together to ask questions, give advice, and share their stories with others who understand life with lung cancer.

Have you been diagnosed with a neuroendocrine tumor of the lung? How did your oncologist diagnose and treat it? Share your experience in the comments below, or start a conversation by posting on your Activities page.