In its early stages, neuroendocrine tumors are usually undetected and typically found during a surgery or x-ray for an unrelated condition. People diagnosed with gastrointestinal-tract neuroendocrine tumors may experience the following tumor-related symptoms or signs:

General cancer symptoms:

• Fatigue
• Loss of appetite
• Unexplained weight loss

Other symptoms (dependent on tumor size and tumor location):

• Abdominal pain
• Nausea and vomiting
• Diarrhea, particularly in people who have had their gallbladder or part of their intestines removed.
• Skin rash
• Scale-like skin sores
• Facial flushing, usually without sweating
• Jaundice
• Bright red blood in your stools or dark tarry stools
• Constipation
• Confusion
• Anxiety
• Hyperglycemia, which can cause frequent urination and increased thirst and hunger
• Hypoglycemia, which can cause fatigue, nervousness and shakiness, dizziness or light-headedness, sweating, seizures and fainting
• Ulcer disease
• Niacin or protein deficiency

There are two types of neuroendocrine tumors: functional and non-functional. Functional neuroendocrine tumors produce an overabundance of hormones, while non-functional neuroendocrine tumors don’t produce enough hormones. Sixty percent of diagnosed neuroendocrine tumors are non-functional. The location where the cancer develops will determine which hormone(s) the cancer cells secrete. Your treatment plan will be determined by your symptoms, if any, and whether the tumor is functional or non-functional.

What are the different classifications of neuroendocrine tumors?

Neuroendocrine tumors can also be classified as indolent (slow-moving) or aggressive. Tumors are usually classified after more information is gathered through testing.

Indolent neuroendocrine tumors

An indolent neuroendocrine tumor, also known as a carcinoid tumor or low-grade neuroendocrine tumor, has cells that look like healthy, noncancerous cells and are slow-growing. This type of neuroendocrine tumor has a lower risk of metastasizing (spreading).

Aggressive neuroendocrine tumors

An aggressive neuroendocrine tumor has cells that look abnormal or different from healthy noncancerous cells. This type of neuroendocrine tumor is fast-growing and considered more aggressive.

Because indolent neuroendocrine tumors look similar to healthy cells, they may not respond as well to chemotherapy as aggressive neuroendocrine tumors would. Learn more about the treatment options for GI tract neuroendocrine tumors.

Tumor grade classes

To determine how fast the cancer is growing and dividing, Banner’s expert cancer specialists may utilize the following grade scales:

• Grade 1 (low grade): Neuroendocrine tumors have cells that look more like healthy cells and are not multiplying quickly. Neuroendocrine tumors with this grade have cells which grow slowly and may spread to other parts of the body.
• Grade 2 (intermediate grade): Neuroendocrine tumors’ cells exhibit a combination of features in grades 1 and 2. Neuroendocrine tumors with this grade have cells which grow slowly and may spread to other parts of the body.
• Grade 3 (high grade): Neuroendocrine tumors have cells that are multiplying quickly and look very abnormal. Cancers with this grade are called gastrointestinal neuroendocrine carcinomas (NECs). They typically grow and spread quickly and can metastasize to other parts of the body.

At Banner Health, our caring staff is here for you to provide support throughout your cancer journey. If you notice changes in your body and/or are exhibiting signs and symptoms, schedule an appointment with your doctor today.