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Understanding Lung NET


What Are Lung Neuroendocrine Tumors?

Lung neuroendocrine tumors, known as lung NET, are a rare form of lung cancer. Some doctors may refer to them as lung carcinoids or bronchial NET. Lung NET start in your lungs, but can spread to the outer area of your lungs.

Lung neuroendocrine cancers are different from other types of lung cancers, because they form in individual or groups of neuroendocrine cells in your lung. Neuroendocrine cells are part of your body’s normal “control system.” When your brain and nervous system send messages, neuroendocrine cells release hormones and other chemical messengers to control bodily functions, like digestion, reproduction, airflow to the lungs, and responses to stress or injury.

There are many subtypes of lung NET, some of which are slow-growing and some of which may be very aggressive. 

Lung carcinoid tumor symptoms you may have

Lung NET usually cause symptoms like coughing and wheezing. Because these symptoms are common, or similar to symptoms that are related to other diseases, it may take a long time for doctors to diagnose a lung neuroendocrine tumor.

There are different types of lung NET, and they are grouped into the following categories:

  • Low-grade typical carcinoid

  • Intermediate-grade atypical carcinoid

  • High-grade small-cell lung carcinoma (SCLC)

  • High-grade large-cell neuroendocrine carcinomas (LCNEC)

Typical and atypical carcinoids are grouped with SCLC and LCNEC, even though there are some differences among them with respect to their aggressiveness, size, and tumor cell activity. Also, people with typical and atypical carcinoids tend to have a better overall prognosis than people with SCLC or LCNEC. In addition, SCLC and LCNEC are more strongly linked to smoking than carcinoid tumors.

It is important to remember that even typical carcinoids can grow and spread (metastasize). Depending on the type of lung carcinoid, 5% to 40% of patients have their disease return after the tumor has been surgically removed and/or develop metastatic disease. Lung NET that has become metastatic can spread to the liver or bones. Therefore, it is important to consult your doctor, who can order scans on a regular basis.

Common symptoms of lung NET:

  • Chronic cough

  • Chest pain

  • Shortness of breath

  • Coughing up of blood

  • Wheezing

  • Inflammation of the lungs

Uncommon syndromes associated with lung NET

Most lung NET are considered “nonfunctional” tumors because the cells do not release the hormones associated with normal neuroendocrine cells. However, some lung NET are “functional” tumors. Functional lung NET are able to create and release hormones—and these hormones can cause distinct symptoms, such as Cushing syndrome and carcinoid syndrome.

Cushing syndrome

Cushing syndrome occurs when a lung NET releases a hormone called adrenocorticotropic hormone (ACTH). ACTH is a hormone that causes your body to make the hormone cortisol. Cortisol helps your body manage stress. Some lung NET can cause your body to produce too much cortisol.

Symptoms of Cushing syndrome include:

  • Weight gain

  • Purple marks across the skin

  • Easy bruising

  • More visible body hair

  • Muscle weakness

Carcinoid syndrome

Carcinoid syndrome occurs when a lung NET releases hormones, including serotonin. Serotonin is made by certain cells in the body and helps with various functions, such as digestion. Carcinoid syndrome is very rare for people with lung NET.

The symptoms of carcinoid syndrome usually become more noticeable when your NET starts to grow or spread (metastasize).

Symptoms of carcinoid syndrome include:

  • Turning red and feeling warm in your face or neck (flushing)

  • Diarrhea, especially at night

  • Wheezing

  • Rapid or abnormal heart rate

  • Discolored skin patches

Diagnosis & Management of Lung NET


Diagnosis of Lung NET

Because lung NET is a rare disease with symptoms similar to those of more common conditions, it is often misdiagnosed. Often, a tumor is only suspected after other treatments have failed. 

There are several tests that your doctor can use to help diagnose lung NET and to monitor it once it has been diagnosed. It’s important to be monitored regularly for changes in your symptoms or test results.

Learn about how these tests are performed.

Tests that can help confirm a lung NET diagnosis

Click each tab below to learn about how these tests are performed.

Imaging Tests

Imaging tests use specialized machines to look at your organs and tissues. These tests may help with diagnosis of NET or to find out whether the tumor has grown or changed.


Computed Tomography

CT scan showing the location and size of a NET

A computed tomography (CT) scan shows the location and size of your tumor. Being scanned over time will help your doctor tell if your tumor has grown, changed, or spread.

How the test is performed

If your doctor orders your test with "contrast," you will either drink a fluid or receive an intravenous (IV) injection before the test. Contrast helps certain areas show up in the images. A CT scanner is shaped like a large doughnut standing on its side. You will lie on a table that slides you into the doughnut hole while the scanner takes pictures. You may also hear clicking or whirring noises. You may need to hold your breath to ensure the pictures are clear.


Magnetic Resonance Imaging

Patient receiving an MRI scan to examine a NET

A magnetic resonance imaging (MRI) scan shows the difference between healthy tissue and a tumor. Being scanned over time will help your doctor tell if your tumor has grown, changed, or spread.

How the test is performed

If your doctor orders your test with "contrast," you will get an IV injection before the test. Contrast helps certain areas show up better in the images. During the test, you will lie on a table while the machine takes pictures. It may make clicking or beeping noises. You need to stay very still to ensure the images are clear.



Octreoscan showing if NET are present

An Octreoscan™ may help find a tumor that may not have been seen by other tests. Being scanned over time will help your doctor tell if your tumor has spread. 

How the test is performed

Before the test, you will get an injection to place a "tracer" into your body. The tracer helps certain areas show up better in the images. You will lie on your back during the scan while the machine takes pictures. You can breathe normally and need to stay still to help make sure the images are clear.

Octreoscan is a trademark of Mallinckrodt Nuclear Medicine LLC.


Gallium Scan

Gallium Scan imaging test

A gallium scan is an imaging test that uses a small amount of a radioactive tracer to help find NET that may otherwise be missed.

How the test is performed

Before the test, your doctor will advise you to drink plenty of water to make sure that you are well hydrated. Then you will receive an IV infusion that contains the tracer solution. You will be instructed to lie still while your body is scanned by a positron emission tomography (PET) device. 

After the scan is completed, you will be instructed to drink plenty of water and urinate frequently to flush the radioactive tracer out of your body.

Biochemical Tests

Biochemical tests measure the levels of certain substances in your blood or urine. Your doctor may order biochemical tests to help determine whether or not you actually have a lung NET or to measure the amount of certain hormones.


Chromogranin A

Chromogranin A (CgA) blood test monitoring activity of carcinoid tumors

The chromogranin A (CgA)* blood test is a good marker to help detect and monitor the activity of lung NET and carcinoid tumors. This includes functional tumors, which are the type that release (secrete) hormones. Elevated levels of CgA are found in 80% to 100% of patients with GI NET or lung NET.

A CgA test is an accurate measure of your CgA level. However, increased levels of this marker may also be caused by other factors, such as renal failure, chronic atrophic gastritis, or the use of proton-pump inhibitors.

You may continue to have this test, so your doctor can measure your CgA levels over time.

How the test is performed

A needle is inserted into your arm to take a sample of blood. The sample is sent to a lab to be tested. Measurements may vary with meal consumption, so patients are required to fast before a CgA test. CgA tests are performed every 3 to 6 months.

 *CgA is a protein found in NET tumor cells, and it may be secreted into the blood. A blood sample is taken, and the level of CgA in the bloodstream is determined.

5-Hydroxyindoleacetic Acid Test

A 5-hydroxyindoleacetic acid (5-HIAA) test is a 24-hour urine test. 5-HIAA testing may be useful in patients with functional lung NET.

Your doctor may order a 5-HIAA test to measure the amount of serotonin in your blood. Serotonin is a hormone mostly made by cells found in the gastrointestinal (GI) tract (digestive system) that helps with various bodily functions, such as digestion. Your doctor may order this test more than once to help watch for a neuroendocrine tumor that may cause carcinoid syndrome.

How the test is performed

You will urinate into a container over a 24-hour period.

After 24 hours, you will return the container to be tested.

Please note that some types of foods and medicines can increase the 5-HIAA detected in your urine, leading to misleading results. Ask your doctor for a complete list of foods and medicines that you should avoid before a 5-HIAA test.

Here are some foods to avoid:

  • Bananas

  • Avocados

  • Plums

  • Eggplants

  • Tomatoes

  • Plantains

  • Pineapples

  • Walnuts

And medicines with:

  • Guaifenesin (found in cough medicine)

  • Acetaminophen (Tylenol®)

  • Salicylates (found in aspirin) 

  • L-DOPA (found in Parkinson disease medicine)

Tylenol is a registered trademark of McNeil Consumer Healthcare.

Management of Lung NET

Management of lung NET depends on several factors, including the state of the disease and size and location of the tumor.

  • Surgical removal is the preferred treatment for a lung carcinoid that has not spread, and it may also be recommended for some patients with advanced or metastatic lung NET

  • For patients whose lung NET has spread and/or cannot be removed, other treatments, such as systemic therapy, may be considered

  • For patients whose lung NET is causing carcinoid syndrome or Cushing syndrome, there are treatments that can help

Ongoing monitoring of lung NET

People who are being treated for lung NET may have testing for chromogranin A (CgA) and 5-hydroxyindoleacetic acid (5-HIAA) repeated every 3 to 6 months. 

In general, with both tests, results that show the numbers going down mean that your disease is under control.

  • CgA levels that are very high (up to 1000 times normal levels) may indicate that carcinoid tumors have spread

  • 5-HIAA testing may be useful in patients with functional lung NET. Elevated levels may indicate carcinoid heart disease

Keeping track of your test results and your symptoms

Keeping records of your CgA or 5-HIAA level (or both) over time can help you keep track of how well your treatment for lung NET is working.

Working With Your Health Care Team


Make the Most of Your Doctor Visits

Having a good relationship with your doctors and health care team is very important, and being prepared for your doctor visits can help make the most of your time.

Your team of health care professionals

Your doctor or oncologist may suggest that you see a team of medical experts to care for your lung NET. This is called a multidisciplinary team. This team can help ensure that you receive the best possible care, because NET can cause different symptoms and can lead to other medical issues.

The HCPs below are specialists who may be part of your multidisciplinary team. There are other HCPs not noted who can also support lung NET patients. Read about the HCPs below to see how they can help care for your carcinoid or lung NET.


Diagnoses and manages different types of cancerous tumors


Treats diseases of the endocrine system, made up of glands that produce and secrete hormones essential to help the body function properly


Performs surgery and removes tumors


Uses a powerful microscope to look at samples of tumors, called a biopsy. This helps determine the type of tumor you have

Nuclear medicine tech

Creates medical pictures of tumors; called "imaging"


Uses imaging tests to diagnose and stage tumors, even those that have spread to other parts of the body


Suggests changes to diet and nutrition that may help improve a patient's health

Nurse practitioner

Works alongside your doctors to care for you in the clinic and the hospital

Social worker

Helps you and your family deal with emotional and social issues, insurance problems, and treatment arrangements

Case manager

Oversees your care from diagnosis to recovery and helps you get the resources you need along the way

Ensure that you talk to your health care team

It's important to tell your health care team everything about your disease, including:

  • Symptoms

  • Allergies

  • Foods you eat

  • All medicines you take (prescription and over-the-counter)

  • Any changes in your daily habits

Be sure to include details about any changes in symptoms or new symptoms, especially if they become worse.

It's also important to share information about your daily life with your doctors, like your work or exercise habits. They will consider all of these details to help create a plan for you to manage your NET.

Ask your health care team questions

Take an active role in your care. Ask your doctors a lot of questions and write down the answers, so you can read them again later. Your doctors want you to ask questions. If there's something you don't understand, ask your doctors to explain more or slow down when speaking.

Keep a regular appointment schedule

Making a commitment to your medical appointments can help you establish a partnership with your health care team. Try to plan your day-to-day calendar far in advance so you won't have to cancel your medical appointment.

Living With Lung NET


What Can You Do to Live With Your Lung NET?

Like all cancer, lung NET can change your life.

If you have been diagnosed with a lung NET, it is normal to feel confused, overwhelmed, afraid, and even angry. Your family and friends may feel the same way, too.

Remember, it's important to learn how to live with your NET. Understanding your condition may help you live as comfortably as possible.

Breathing exercises

Taking a deep breath may be difficult for someone with a lung NET because of stress or respiratory symptoms. Read about some breathing exercises below. 

  • Take a deep breath through your nose
  • Breathe in for about 5 seconds or whatever is comfortable for you
  • Hold this breath in your chest for about 2 seconds
  • Then exhale through your mouth
  • Keep exhaling for 5 seconds
  • While exhaling, press your belly button toward your spine

Step 1: Breathe in with your diaphragm

  • Sit in a chair or stand up—your choice
  • Place your hand on your belly
  • Breathe in deeply through your nose
  • While inhaling, push your belly out gently
  • Allow your hand to move outward

Step 2: Breathe out with pursed lips

  • Pucker your lips and exhale slowly through your mouth
  • Push gently in and up on your belly to help empty the lungs
  • Press your belly button toward your spine while exhaling all the air

Step 3: Breathe back in and repeat

  • Finally, inhale slowly and fill your lungs with air
  • Repeat this exercise several times a day

Ask your doctor if these breathing exercises are right for you. When doing these exercises, be careful not to breathe in too deeply for a long time to avoid getting dizzy.

Maintain a healthy lifestyle

Your doctor may suggest some things you can do to help make living with a lung NET as comfortable as possible.

  • Adjust your diet: Eating certain types of food may help reduce symptoms

  • Light exercise: Mild activity, such as walking, is best and can help reduce stress

  • Get a good night's sleep: Get plenty of sleep and take naps when you can

  • Avoid stress: Make time for yourself to do things you enjoy and keep a positive attitude

Continue your daily routine

Your family members and caregivers will be there for you throughout this journey. Don't be afraid to ask them for help. They can help you with daily activities and also help you cope with your feelings. They understand that the most important thing is for them to be there for you.

Your loved ones can help:

  • Provide emotional support

  • Take notes and ask questions at your doctor appointments

  • Keep track of your appointments and paperwork

  • Drive you to your appointments

  • Prepare meals and do the grocery shopping

Let the people in your life know how you feel and what you are going through. Asking them to be more involved can help you continue your regular routines.

Build a support network

In addition to your family, friends, and caregivers, there are other people like you and patient advocacy groups who want to help you. These groups work to improve the lives of people living with NET through support, awareness, education, research, and advocacy.

Building a support network is a great way to learn about your lung NET and get more engaged with your care. You should ask your doctor or nurse for information about groups in your area.

Tools, Resources, and Support


Learn About Available NET Resources


Galaxies of Hope

Embark on an interactive journey with the NET cancer community to gain a better understanding of your diagnosis. Navigate your emotional landscape, hear from real patients with NET cancer along the way, and find comfort in a galaxy created with you in mind.

Begin your journey.

Start exploring the Galaxies of Hope app by downloading on your mobile device or tablet!


Galaxies of Hope

Embark on an interactive journey with the NET cancer community to gain a better understanding of your diagnosis. Navigate your emotional landscape, hear from real patients with NET cancer along the way, and find comfort in a galaxy created with you in mind.

Begin your journey.

Start exploring the Galaxies of Hope app by downloading on your mobile device or tablet!

30-Second carcinoid syndrome test

Download this 30-second test to help you identify and understand potential symptoms that could be a sign of carcinoid syndrome.

Simply download, answer the questions, and share with your doctor or nurse at your next appointment, so he or she can review with you and determine the next appropriate steps.

Lung NET overview
Lung NET overview

Learn about lung NET with this overview of its symptoms, diagnosis, and management.

NET journey road map

See the pathway of dealing with NET, from prior to official diagnosis, to treatment and beyond. Also learn how your doctor is there to help along the way.

Find Support Groups

You may have an uncommon disease, but you are not alone. Learn more about the patient advocacy and support groups for patients with NET and their families by visiting any of the below websites. Novartis is neither affiliated with nor endorses these organizations. The information provided by the organizations is meant for informational purposes only and is not meant to replace your doctor's medical advice.


Carcinoid Cancer Foundation


Healing NET Foundation




Los Angeles Carcinoid Neuroendocrine Tumor Society



Neuroendocrine Cancer Awareness Network



Neuroendocrine Tumor Research Foundation


NorCal CarciNET

Northern California CarciNET Community


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