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 NETs, 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 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 NET depends on:
- how quickly cells divide to make new tumour cells (called the mitotic count)
- the amount of protein (called Ki-67) cells make when they divide
- how many dead cells there are (necrosis).
NETs are usually divided into three groups:
- Well differentiated – the cells look like normal cells and are usually slow-growing.
- Moderately differentiated – the cells look more abnormal.
- Poorly differentiated – the cells look very abnormal. They are likely to grow more quickly and spread.