Neuroendocrine Tumour of the Lung

Lung neuroendocrine tumours are a rare but important group of cancers that develop in specialized cells within the lungs, with each type having its own characteristics, treatment approaches, and outlook for patients.

Table of contents

• What are lung neuroendocrine tumours?
• Different types of lung neuroendocrine tumours
• How common are these tumours?
• Risk factors and causes
• Signs and symptoms
• Diagnosis and testing
• Treatment approaches
• Outlook and survival rates
• Living with lung neuroendocrine tumours

What are lung neuroendocrine tumours?

Lung neuroendocrine tumours are a group of cancers that start in the neuroendocrine cells of the lung^[1]. These are special cells found throughout your body that have features similar to both nerve cells, which send and receive signals from the brain, and hormone-making cells that control various body functions^[7].

In the lungs, neuroendocrine cells make hormones that help control the flow of air and blood^[3]. When these cells become cancerous, they form neuroendocrine tumours.

• Lungs
• Airways (bronchi)
• Windpipe (trachea)

Lung neuroendocrine cancer can start in any part of the lungs or airways, which are part of your breathing system. The right lung is divided into 3 sections called lobes, while the left lung has 2 lobes^[3].

Different types of lung neuroendocrine tumours

There are two main groups of lung neuroendocrine cancers: neuroendocrine tumours (NETs) and neuroendocrine carcinomas (NECs)^[3]. These two groups are very different, so it’s important to know which type you have.

Typical carcinoid

Typical carcinoids are slow-growing tumours that make up the majority of lung NET cases. They tend to have a good outlook when found early^[1]. The 5-year survival rate for typical carcinoid tumours diagnosed at an early stage is estimated to be around 85% to 95%^[1].

Atypical carcinoid

Atypical carcinoid tumours also grow slowly but are considered more aggressive than typical carcinoids. They have a slightly higher risk of spreading to other parts of the body^[1]. The 5-year survival rate for atypical carcinoids can range from 40% to 70%, with better outcomes when the tumour is found early^[1].

Small cell carcinoma

Small cell carcinoma is the most aggressive type of lung NET. It tends to grow rapidly and is often found at an advanced stage, making treatment more difficult^[1]. The outlook for small cell carcinoma is generally less favorable than for carcinoid tumours. The 5-year survival rate typically ranges from 20% to 30%^[1].

Large cell neuroendocrine carcinoma

Large cell neuroendocrine carcinoma (LCNEC) is a rare and aggressive type of lung tumour. It has features of both small cell lung cancer and non-small cell lung cancer^[1].

How common are these tumours?

Around 20 out of every 100 lung cancers (about 20%) diagnosed each year are lung neuroendocrine cancers^[3]. Most of these are a type called small cell neuroendocrine carcinoma.

Breaking this down further^[3]:

• 15 out of 100 lung cancers (15%) are small cell neuroendocrine carcinomas
• Around 3 out of 100 lung cancers (about 3%) are large cell neuroendocrine carcinomas
• Around 2 out of 100 lung cancers (about 2%) are lung neuroendocrine tumours (also called carcinoids)

Although most neuroendocrine cancers start in the digestive system, the lungs are the second most common place. Around 20 out of every 100 neuroendocrine cancers (about 20%) diagnosed in the UK start in the lungs^[3].

Risk factors and causes

Like many other cancers, the exact cause of lung neuroendocrine tumours remains unclear^[1]. However, several factors may increase the likelihood of developing these tumours.

Genetic factors

In some cases, a family history of lung NETs or certain genetic conditions can increase risk. One such condition is multiple endocrine neoplasia type 1 (MEN1), which can elevate the risk of developing these tumours^[1][3].

Age and gender

Lung NETs often affect people in their 40s and 50s^[1].

Smoking

Smoking is listed as a risk factor for lung neuroendocrine cancer^[3].

Previous history of cancer

Having had cancer before can increase the risk of developing lung neuroendocrine cancer^[3].

Signs and symptoms

Some people don’t have symptoms at all. Doctors may diagnose lung neuroendocrine tumours when doing tests for something else^[3]. When symptoms do appear, they are usually caused by the growth of the cancer in your lung or airway, the cancer spreading to other parts of the body, or hormones made by the cancer^[3].

Common symptoms

Symptoms of lung neuroendocrine cancer might include^[3]:

• A cough that doesn’t go away
• Wheezing
• Coughing up blood
• Feeling short of breath
• Aching or pain in your chest
• Ongoing chest infections
• Feeling very tired (fatigue)
• Unexplained weight loss

Symptoms caused by hormones

Some lung neuroendocrine tumours make extra hormones and release them into the bloodstream. This is less common in lung NETs compared to NETs that start in the digestive system^[3].

These hormones can cause a collection of symptoms called carcinoid syndrome, which includes^[3]:

• Skin flushing (reddening)
• Diarrhea
• Wheezing
• Fast heart beat

Carcinoid syndrome is more likely to happen if the lung NET has spread to other parts of the body, especially the liver^[3].

It’s important to remember that these symptoms could be due to other medical conditions as well. If you experience any of these symptoms, it’s important to see your doctor^[3].

Diagnosis and testing

Diagnosis of neuroendocrine tumours often starts with a physical exam. A healthcare professional might check your body for signs of cancer, such as swollen lymph nodes or signs that a tumour is producing excess hormones^[11].

Blood and urine tests

Your healthcare professional may recommend testing your blood or urine for signs of extra hormones that some neuroendocrine tumours produce^[11].

Imaging tests

Imaging tests create pictures of the inside of your body. For neuroendocrine tumours, these can show the cancer’s location and size, and whether it has spread^[11].

Imaging tests might include^[11]:

• Ultrasound
• Computerized tomography (CT) scan
• Magnetic resonance imaging (MRI) scan
• Positron emission tomography (PET) scan with a special tracer

Biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. Tests can show whether cancer cells are present. How a biopsy is done depends on where the cancer is in the body^[11].

Treatment approaches

The treatment you receive depends on several factors, including where the cancer started in your lung, the type of lung neuroendocrine cancer, whether it has spread, how fast the cells are growing, your symptoms, and your general health^[8].

A team of doctors and other professionals will discuss the best treatment and care for you. This is called a multidisciplinary team^[8].

Surgery

The main treatment for lung NETs is surgery. Surgery might be all the treatment you need if your cancer hasn’t spread^[8]. There are different types of operations to remove cancer from the lung, including^[8]:

• A lobectomy (removing a section of the lung)
• A bilobectomy (removing 2 lobes of the lung)
• A segmentectomy (removing an area of the lung along with the veins, arteries and airways)
• A pneumonectomy (removing the whole lung)

Other treatments for lung NETs

Besides surgery, other treatment options for lung NETs include^[8]:

• Somatostatin analogues
• Chemotherapy
• Targeted cancer drugs
• Surgery or other treatments for cancer that has spread to the liver

Treatments for lung NECs

For lung NECs, you might have^[8]:

• Surgery
• Chemotherapy
• Immunotherapy
• Radiotherapy
• Treatment for cancer that has spread to the liver

Some lung NETs grow slowly, and some might not grow at all for months or years. In these cases, you might not need treatment straight away. Your doctor might just keep an eye on it with regular tests^[8].

Outlook and survival rates

The outlook for lung neuroendocrine tumours varies greatly depending on the type of tumour and when it is diagnosed. Many are curable or can be controlled for many years^[13].

Advances in medical treatments, including surgery, chemotherapy, radiation therapy, and targeted therapies, have improved outcomes for some patients with lung NETs^[1]. It’s important to remember that survival rates are approximate and can vary based on individual circumstances.

Not everyone wants to know about their prognosis, and that’s okay. If you do want to know about your likely outlook, the best person to talk to is your doctor or specialist nurse^[13].

Living with lung neuroendocrine tumours

Managing emotions

You might have a number of different feelings when you’re told you have cancer. You may feel shocked, upset, frightened, uncertain, confused, angry, guilty, or sad^[13]. These feelings are normal, and everyone reacts in their own way.

Talking to your friends and relatives about your cancer can help and support you. If you find it difficult to talk to those close to you, you might find it easier to talk to someone else, such as a counselor^[13].

Getting information

You may be more able to cope and make decisions if you have information about your type of cancer and its treatment. Taking in information can be difficult, especially when you have just been diagnosed. Make a list of questions before you see your doctor, and take someone with you to help you remember what was said^[13].

Diet and nutrition

Some people with NETs have a group of symptoms called carcinoid syndrome. If that happens to you, certain foods and drinks may trigger problems like skin flushing, painful gas and bloating, and severe diarrhea^[17].

Foods high in substances called amines may cause these problems. These include^[17]:

• Aged or blue cheeses
• Chocolate
• Red wine and beer
• Smoked meats like salami or sausage
• Pickled fish
• Fermented foods like miso or sauerkraut

Eating healthy foods can keep your strength and energy up while you get treatment. Some tips that may help^[17]:

• Eat smaller, frequent meals
• Avoid fatty, greasy, or highly spicy foods
• Choose whole, natural foods over processed ones high in salt

Exercise and lifestyle

While no diet or vitamin can treat your disease, a healthy lifestyle can help you feel better in general. Keep up with exercise, such as taking a half-hour walk three times a week or more^[17].

Support networks

It’s natural to feel anxious, stressed out, and sometimes depressed when you find out you have a NET. Setting up a support network you can rely on is important. You might benefit from going to a support group for people who have NETs^[17].

Living with neuroendocrine cancer can often feel like riding a rollercoaster, with its ups and downs and moments of uncertainty^[14]. Remember that there are medical professionals and support networks available to provide guidance, care, and compassion throughout the process^[1].