How are NETs diagnosed?
NETs can be difficult to find and are sometimes diagnosed when patients are undergoing tests for a different condition.
Many doctors may not have seen or treated Merkel cell carcinoma before, so diagnosis is often delayed. It is a good idea to seek urgent review by a specialist connected with a skin cancer multi-disciplinary team.
If your doctor thinks that you may have a NET (or one of the syndromes associated with NETs) they will take your medical history, perform a physical examination and carry out certain tests. If the results suggest that you may have a NET, your doctor will refer you to a specialist who will carry out further tests.
Blood tests – including a full blood count to measure your white blood cells, red blood cells and platelets and chromogranin A (a hormone marker).
Urine tests – to measure serotonin production (which can be produced by NETs).
Endoscopy – a flexible tube with a camera on the end (endoscope) is inserted under sedation down the throat into the stomach, or into the anus and large bowel to view your gut.
Bronchoscopy – a thin, tube-like instrument with a light and a lens for viewing (bronchoscope) is inserted through the nose or mouth to view your lungs. The bronchoscope is also able to remove tissue to obtain a diagnosis.
CT (computerised tomography) or MRI (magnetic resonance imaging) scans – special machines are used to scan and create pictures of the inside of your body. Before the scan you may have an injection of dye (called contrast) into one of your veins, which makes the pictures clearer. During the scan, you will need to lie still on an examination table. For a CT scan the table moves in and out of the scanner which is large and round like a doughnut; the scan takes about 10 minutes. For an MRI scan the table slides into a large metal tube that is open at both ends; the scan takes about 30–90 minutes. Both scans are painless.
PET (positron emission tomography) scan – before the scan you will be injected with a small dose of radioactive glucose (sugar) solution. Many cancer cells will show up brighter on the scan. You will be asked to sit quietly for 30–90 minutes to allow the glucose to move around your body. The scan will take around 30 minutes to perform. There are two different types of PET scans used in NETs – Gallium-68 Dotatate (also called Gatate scans) and fluorodeoxyglucose (FDG). Which scan you have will depend on the type and grade of tumour.
Biopsy – removal of some tissue from the affected area for examination under a microscope. The biopsy may be done in one of two ways. In a needle biopsy, a local anaesthetic is used to numb the area, then a thin needle is inserted into the tumour under ultrasound or CT guidance. An open or surgical biopsy is done under general anaesthesia. The surgeon will cut through the skin to expose the affected area and take a tissue sample.
Echocardiogram – a painless ultrasound to examine your heart valves, which can sometimes be affected, and takes around 30–60 minutes.
Finding a NETs specialist
NeuroEndocrine Cancer Australia can be contacted for a directory of specialists in NET care and treatment.
Australasian Merkel Cell Carcinoma Interest Group (AMIGOs) can be contacted for a directory of specialists in Merkel cell carcinoma care and treatment.
This information is reviewed by
This information was last reviewed February 2021 by the following expert content reviewers: Dr David Chan, Medical Oncologist, Royal North Shore Hospital, NSW; Leslye Dunn, Consumer; Prof Gerald Fogarty, Radiation Oncologist, St Vincent’s Hospital, NSW; Katie Golden, Consumer; Dr Grace Kong, Nuclear Medicine Physician, Peter MacCallum Cancer Centre, VIC; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Elizabeth Paton, Melanoma and Skin Cancer Trials Group, NSW.