Staging and grading of neuroendocrine tumours (NETs)
Staging of neuroendocrine tumours NETs
Tumours that develop from the neuroendocrine cells are known as neuroendocrine neoplasms (NENs). Most NENs are called neuroendocrine tumours (NETs) but depending on the grade, a smaller number are described as neuroendocrine carcinomas (NECs).
The stage of a cancer describes its size and whether it has spread beyond its original site. Knowing the stage of the cancer helps the doctors decide the best treatment for you.
There is no standard staging system for NENs, but doctors may divide them into three stages:
- Localised – the cancer is contained inside the organ where it started. For example, this could be the appendix, bowel or stomach.
- Regional spread – the cancer is growing through the wall of the organ into nearby tissues. It may also have spread to nearby lymph nodes.
- Distant spread (metastatic) – the cancer has spread to other parts of the body, such as the liver, bones or lungs.
Grading of neuroendocrine tumours (NETs)
Grading describes how tumour cells look under a microscope. It shows how abnormal the cells are. It can give an idea of how quickly the tumour may develop. This helps the doctors decide on the best treatment for you.
The grade of a NEN depends on:
- how quickly cells divide to make new tumour cells – a number called the mitotic count
- the amount of protein called Ki-67 cells make when they divide – this is described as a percentage
- how many dead cells there are – this is called necrosis.
Grading is also based on whether the cells are:
- Well differentiated – the cells have a mitotic count of less than 20 and less than 20% Ki-67. The cells look like normal cells and are usually slow-growing. These tumours are described as neuroendocrine tumours (NETs).
- Poorly differentiated – the cells have a mitotic count of more than 20 and more than 20% Ki-67. The cells look very abnormal. They are likely to grow more quickly and spread. These tumours are described as neuroendocrine carcinomas (NECs).
Your doctor will describe your tumour as grade 1, 2 or 3 depending on how the cells look, the mitotic count, and the amount of Ki-67.
About our information
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References
Below is a sample of the sources used in our neuroendocrine tumours (NETs) information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
Esmo clinical practice guidelines: endocrine and neuroendocrine cancers. Available from: www.esmo.org/guidelines/endocrine-and-neuroendocrine-cancers (accessed May 2021). -
Reviewers
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr Paul Ross, Consultant Medical Oncologist.
Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information
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Reviewers
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.
Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.
Date reviewed
Our cancer information meets the PIF TICK quality mark.
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