Neuroendocrine Cancer

Neuroendocrine cancers are a group of cancers that develop in cells of the neuroendocrine system.

They can develop in different parts of the body, such as the stomach, bowel, pancreas or lungs.You might also hear them called neuroendocrine neoplasms (NENs). This means the same as neuroendocrine cancer.

There are 2 key groups of neuroendocrine cancer:

• neuroendocrine tumours (NETs )
• neuroendocrine carcinomas (NECs )

Neuroendocrine tumors (NETs)

Neuroendocrine tumors (NETs) are a group of uncommon tumors that start in specialised cells in your neuroendocrine system. They’re most common in your GI tract, lungs and pancreas but can form wherever neuroendocrine cells are in your body. Early diagnosis and treatment continue to increase the number of people living for years with NET.

Types of neuroendocrine tumors

Researchers classify NETs based on whether they release hormones:

• Functional NETs release hormones and can cause hormone-related symptoms.
• Non-functional NETs don’t release hormones. They can still cause symptoms if they impact an organ.

Researchers also classify neuroendocrine tumors based on where the tumor starts in your body. The most common types include:

• Gastrointestinal neuroendocrine tumors (GI-NETs): NETs most commonly start in your gastrointestinal (GI) tract. Most start in your intestines, rectum or appendix. GI-NETs used to be called carcinoid tumors.
• Lung neuroendocrine tumors: These tumors start in your lungs or bronchi, the tubes that carry air from your windpipe to your lungs. They’re the second most common type of NET and were also once called carcinoid tumors.
• Pancreatic neuroendocrine tumors (P-NETs): These tumors start in your pancreas and are a type of pancreatic cancer. P-NETs are the third most common type of NET.

Less often, NETs may start in your:

• Thyroid gland.
• Parathyroid glands.
• Pituitary gland.
• Adrenal glands.
• Thymus.

Symptoms

Often, neuroendocrine tumors don’t cause symptoms until a tumor impacts an organ. When this happens, symptoms vary based on location. NET symptoms may include:

• Fatigue.
• Stomach pain.
• Diarrhea.
• Nausea and vomiting.
• Shortness of breath.
• Coughing (sometimes with blood).

It’s important to remember that having these symptoms doesn’t always mean you have cancer. Talk to a healthcare provider if you’re experiencing symptoms that don’t improve.

FAQ

What can I expect if I have a NET?

NETs are often mistaken for other less serious conditions, so it may take some time before you’re diagnosed. Once you learn you have a neuroendocrine tumor, your prognosis, or expected outcome, depends on several factors, including the type of NET you have and whether your tumor has spread. On average, an estimated 39% of people with NETs are alive five years after diagnosis.

But statistics on life expectancy and survival rates vary. For example, the average survival rate for people with NETs that haven’t spread is as high as 30 years. Your healthcare provider can explain what factors shape your outlook.

In the meantime, keep in mind that finishing treatment is a major milestone but not the end of your NET journey. NETs can grow very slowly and recur (return) after treatment, so your healthcare provider will want to track your well-being for several years.

Can a neuroendocrine tumor be cured?

NETs are curable when your healthcare provider can remove all signs of the tumor with surgery. But one of the biggest challenges with this diagnosis is that although most NETs are slow-growing, they’ve often spread by the time they’re caught.

At this point, treatment can help slow tumor growth and provide symptom relief.

Prevention

Can I prevent neuroendocrine tumors?

As researchers don’t know what causes NETs, there’s nothing you can do to prevent them. Still, you can understand potential risk factors, like having an inherited condition like multiple endocrine neoplasia (MEN).

Ask your healthcare provider for help understanding whether your family health history puts you at risk of developing NETs.

Neuroendocrine carcinoma (NEC)

Neuroendocrine carcinomas (NECs) are cancers that start in the neuroendocrine system. They can develop in different parts of the body, such as the stomach, bowel, pancreas or lungs.

The cells of NECs look very abnormal. They are not like normal neuroendocrine cells at all. Doctors call them poorly differentiated cancers. They are also fast growing and are likely to spread.

What is the difference between neuroendocrine carcinomas (NECs) and neuroendocrine tumours (NETs)?

A specialist doctor (pathologist) looks at the cancer cells under a microscope. This is to find out what type of cancer you have. They check to see whether the cells look normal or not. If they are abnormal, the pathologist reports:

• how abnormal they look – this is called differentiation
• how quickly or slowly the cancer cells are dividing and growing – this is called grading

Neuroendocrine Tumours (NETs)

• NETs are well differentiated cancers. This means they look abnormal. But they still have some similarities to normal neuroendocrine cells.
• NETs may be grade 1, 2 or 3. This means they can be slow, medium or fast growing.

Neuroendocrine Carcinomas (NECs)

• NECs are poorly differentiated cancers. This means they look very abnormal and are not like normal neuroendocrine cells at all.
• Doctors don’t usually give NECs a grade. This is because they are all fast growing (high grade).
• There are different types of NEC, depending on what the cells look like. The main types are small cell NEC and large cell NEC.

Can NECs disrupt hormones and cause symptoms?

Neuroendocrine cancer can disrupt how much hormone

the neuroendocrine cells make and release. It is much more common for NETs to produce abnormal levels of hormone than NECs. This can cause symptoms. If a NET makes and releases abnormal levels of hormone, doctors call it a functioning NET.

Note — NECs are rarely functioning. They almost never have symptoms linked to making an abnormal amount of hormones.

Types of neuroendocrine carcinoma (NEC)

Doctors group NECs depending on where they start to develop. This is called the primary site. For example, a lung NEC starts to develop in the lung.

They also group NEC depending on what the cancer cells look like. There are different types including:

• small cell NEC
• large cell NEC

You can also get neuroendocrine cancer cells mixed in a tumour with a different type of cancer. Doctors call this MiNEN or mixed cell carcinoma.

Symptoms

• a swollen, tender, or discolored belly,
• feeding problems,
• vomiting (often green),
• diarrhea or bloody stools,
• lethargy,
• unstable body temperature,
• slow heart rate, and
• breathing issues like apnea.

FAQ

Can NEC be cured?

Your treatment depends on your:

• primary site - this is where the NEC starts to grow
• type - this is either small cell, large cell or mixed cell
• stage - this means the size of the cancer and whether it has spread
• general health and wellbeing

NEC can be harder to treat than NETs. This is because they are fast growing and have often spread to other parts of the body.

Your prognosis is better if you have an early stage NEC that has not spread. In a few cases, it might be possible for the surgeon to completely remove your cancer. But there is often a high chance that the cancer will come back.

Prognosis is also affected by:

• where the NEC started in your body
• whether you have a large or small cell carcinoma
• your general health and fitness