Neuroendocrine Carcinoma

Neuroendocrine carcinomas are fast-growing cancers that develop from specialized cells throughout the body, most commonly affecting the digestive system, lungs, and pancreas, with symptoms varying widely depending on where the cancer is located and whether it produces hormones.

Table of contents

• What Are Neuroendocrine Carcinomas?
• The Difference Between NETs and NECs
• Where Neuroendocrine Carcinomas Occur
• What Causes Neuroendocrine Carcinomas
• Symptoms of Neuroendocrine Carcinomas
• How Neuroendocrine Carcinomas Are Diagnosed
• Treatment Options

What Are Neuroendocrine Carcinomas?

Neuroendocrine carcinomas are cancers that start in neuroendocrine cells, which are specialized cells found throughout the body. These cells have unique characteristics because they combine traits of nerve cells and hormone-producing cells. Neuroendocrine cells receive signals from the brain and respond by making hormones that help control important body functions such as digestion, heart rate, and sleep^[3].

Neuroendocrine carcinomas belong to a larger group of diseases called neuroendocrine neoplasms (NENs). Within this group, there are two main types: neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs). These two types behave very differently, and it is important for patients to understand which type they have^[6].

The Difference Between NETs and NECs

Neuroendocrine carcinomas are distinct from neuroendocrine tumors in several important ways. NECs are poorly differentiated cancers, which means their cells look very abnormal and very different from normal neuroendocrine cells when examined under a microscope^[6].

All neuroendocrine carcinomas are fast-growing cancers. Doctors typically classify them as small cell or large cell in appearance, but they don’t usually assign them a grade because all NECs grow quickly^[6]. In contrast, neuroendocrine tumors can grow slowly, at a moderate pace, or quickly, and their cells still look somewhat similar to normal neuroendocrine cells^[6].

Where Neuroendocrine Carcinomas Occur

Neuroendocrine carcinomas can develop anywhere in the body where neuroendocrine cells are present. However, they most commonly occur in the digestive tract. They can also develop in the lungs, pancreas, endocrine glands, skin, and reproductive system^[3].

• Digestive tract
• Lungs
• Pancreas
• Endocrine glands
• Skin
• Reproductive system

Neuroendocrine cells are located in almost all organs and endocrine glands throughout the body, including the food pipe, stomach, small and large bowel, appendix, and lungs^[6].

What Causes Neuroendocrine Carcinomas

Neuroendocrine carcinomas form when neuroendocrine cells begin to divide and multiply uncontrollably. Eventually, these abnormal cells become tumors that can affect the organs where the cells are located. Researchers don’t know exactly what triggers this abnormal cell growth^[2].

While most neuroendocrine carcinomas appear without a clear cause, researchers have identified certain inherited conditions that increase the risk of developing these cancers. Neuroendocrine carcinomas have been linked to rare inherited syndromes that involve changes in certain genes. One example is Multiple Endocrine Neoplasia (MEN), a condition that causes overactive tumors to form in various organs and endocrine system glands. Type 1 MEN (MEN1) is the most common cancer syndrome associated with neuroendocrine neoplasms^[2].

Symptoms of Neuroendocrine Carcinomas

The symptoms of neuroendocrine carcinomas vary widely based on where the cancer is located in the body, whether it makes hormones, and which hormones it produces^[3]. Often, neuroendocrine tumors and carcinomas don’t cause symptoms until the tumor impacts an organ^[2].

Common 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. Many less serious conditions can cause similar symptoms. However, if you’re experiencing symptoms that don’t improve, talk to a healthcare provider^[2].

How Neuroendocrine Carcinomas Are Diagnosed

Diagnosing a neuroendocrine carcinoma often starts with a physical examination. A healthcare professional might check your body for signs of cancer, such as swollen lymph nodes or signs that the tumor is producing excess hormones. They may also ask about your symptoms^[10].

Several tests may be used to diagnose neuroendocrine carcinomas:

Blood and urine tests can check for signs of excess hormones. Some neuroendocrine carcinomas make large amounts of hormones, and these tests can detect abnormal hormone levels^[10].

Imaging tests create pictures of the inside of the body and show the cancer’s location and size. If there’s a risk that the cancer may have spread, imaging tests can look for that too. Common imaging tests include ultrasound, computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, and specialized positron emission tomography (PET) scans^[10].

A biopsy is a procedure to remove a sample of tissue for testing in a laboratory. In the lab, specialists can examine whether cancer cells are present and determine their characteristics. How a biopsy is done depends on where the cancer is located in the body^[10].

A specialist doctor called a pathologist looks at the cancer cells under a microscope and reports how abnormal the cells look and how quickly the cancer cells are dividing and growing. This information helps determine whether the disease is a neuroendocrine tumor or a neuroendocrine carcinoma^[6].

Treatment Options

Treatment for neuroendocrine carcinomas varies depending on several factors, including the type of tumor, its location, whether it produces excess hormones, how aggressive it is, and whether it has spread to other parts of the body^[1].

Chemotherapy is a common treatment for neuroendocrine carcinomas. This treatment uses anti-cancer drugs to destroy cancer cells. Chemotherapy is typically used for NECs or for tumors that have spread to other parts of the body^[13].

In some cases, surgery may be part of the treatment plan. Surgery can be performed to remove the tumor and any affected lymph nodes, or to reduce the tumor’s size to help relieve symptoms such as pain^[14].

Radiation therapy uses high-energy rays to destroy cancer cells. This treatment may be recommended in certain situations depending on the tumor’s characteristics and location^[13].

Other treatment options may include targeted therapy drugs, which can change the way cells work and help the body control tumor growth, and immunotherapy, which helps the immune system attack cancer cells^[13].

Because neuroendocrine carcinomas are complex diseases, treatment requires a highly skilled team of medical oncologists, radiation oncologists, surgeons, nuclear medicine specialists, and others working together^[14]. Many specialized cancer centers offer access to clinical trials, which test new treatments that may benefit patients^[14].