Testing for NET & Carcinoid Syndrome

Testing for NETs and Carcinoid Syndrome

NETs and Carcinoid Syndrome are rare and can be difficult to diagnose. Fortunately, there are tests that can help your healthcare team diagnose, treat, and monitor your condition. Your doctor will determine which option is best for you.

Tests for NETs and Carcinoid Syndrome are used to detect:

Presence of disease

Progress of disease

Effects of treatment

Testing options:

  • Biomarkers

    Blood, urine, or tissue samples are taken and checked for signs of disease. These signs are known as biomarkers.

  • Scans

    Images of your body are taken and used to see what’s going on inside your body.

NET Biomarkers
What is CgA?

CgA is a protein found in the secretory granules of neuroendocrine cells.

What is it used for?
  • Detecting size, progression of NETs
  • Measuring response to treatment
How is the test taken?

Blood samples are measured for CgA.

What do the results mean?

Higher than normal levels of CgA may mean a NET is present in the body.

What is Ki-67?

Ki-67 is a biomarker expressed by dividing tumor cells. The mitotic rate is used to measure the amount of cells being replicated.

What is the test used for?

Detecting and measuring tumor cells to monitor disease progression and develop treatment plans.

How is the test taken?

Tissue samples are tested for Ki-67.

What do the results mean?

A high percentage of Ki-67 or mitotic rate (20% or higher Ki-67 index) may mean the NET will grow and spread quickly.

What is Pancreastatin?

Pancreastatin is a protein secreted by neuroendocrine cells.

What is the test used for?
  • Diagnosing NETs
  • Detecting disease progression
  • Monitoring treatment response
  • Predicting disease outcome (prognosis)
How is the test taken?

Plasma (blood) samples are tested for pancreastatin.

What do the results mean?

Higher than normal levels of pancreastatin (135 pg/mL and above) may mean the NET will continue to grow and progress.

What is Neurokinin A?

Neurokinin A is a molecule made up of amino acids secreted by midgut carcinoid tumors.

What is the test used for?

Predicting disease outcome (prognosis).

How is the test taken?

Blood samples are tested for neurokinin A.

What do the results mean?
  • Levels of neurokinin A which continue to rise despite somatostatin analog (SSA) treatment may mean a poor disease outlook
    • Higher than normal levels of neurokinin A means the test may need to be repeated
  • Decreasing levels of neurokinin A with SSA treatment may mean an improved disease outlook
NET Scans
What is a SRS scan?

The SRS is used to detect widespread tumors. There are receptors on the tumors that bind to drugs like somatostatin, which is injected with radioactive material and used in the scan.

What is the scan used for?
  • Diagnosing NETs
  • Detecting NET location
  • Understanding the severity or spread of primary tumor(s) across the whole body
How does it work?
  1. 4-6 hours before the initial scan, an injection of a radioactive drug which attaches to tumor cells is given.
  2. The whole body is scanned for tumors using a device which detects the radioactive drug.
  3. A second scan is performed 96 hours after injection.
What do the results mean?
  • Positive results may mean a NET is present in the body
  • Negative results may mean NETs are not present in the body
What is a PET scan?

A PET scan has a shorter wait time than SRS scans. PETs can detect tumors by finding areas of increased cell activity. They can detect metastasizing tumors better than primary NETs, due to their high activity level.

What is the scan used for?

Locating midgut carcinoid primary and metastasized tumors and monitoring treatment response.

How does it work?
  1. 1 hour before the scan, an injection of a radioactive sugar is given.
  2. You lie on a table and slide through a PET machine.
  3. Cancer cells use more sugar and appear brighter than normal cells on the scan.
What do the results mean?
  • Positive results may mean a NET is present in the body
  • Negative results may mean NETs are not present in the body
What is a Gallium 68 PET scan?

Gallium 68 is a part of the next generation of technology being used in PET scans. Unlike the conventional PET scan which uses sugar, this scan detects tumors using a molecule called Gallium 68.

What is the scan used for?

Locating hard-to-find tumors.

How does it work?
  1. An injection of Gallium 68 is given.
  2. You lie on a table and slide through a PET machine.
  3. Gallium 68 indicates tumor location on scan.
What do results show?

Where NETs are located and may have spread inside your body.

What do the results mean?
  • Positive results may mean a NET is present in the body
  • Negative results may mean NETs are not present in the body
Carcinoid Syndrome Biomarkers and Tests
What is 5-HIAA?

When serotonin breaks down in the body, it becomes 5-HIAA.

What is the test used for?
  • Diagnostic purposes
  • Measuring serotonin levels
How is the test taken?

Urine or plasma (blood) samples are measured for 5-HIAA. Foods with serotonin such as butternuts, black walnuts, pecans, pineapple, and bananas should be avoided for 24 hours before the test.

What do the results mean?

Higher than normal levels may mean Carcinoid Syndrome is worsening.

What is serotonin?

Serotonin is a hormone that helps control mood and digestion. When too much serotonin is produced by NETs, it can cause Carcinoid Syndrome.

What is the test used for?
  • Diagnosis
  • Monitoring disease progression and treatment response
How is the test taken?

Blood samples are measured for serotonin.

What do the results mean?

High levels may mean Carcinoid Syndrome is present.

Remember: Talk to your doctor about tests used to diagnose and monitor your condition.