Grades of Neuroendocrine (NET) Cancers
What G1, G2 and G3 mean for a neuroendocrine cancer diagnosis – plain-language explanation of grade, Ki-67, and how they shape treatment options.
Grades of Neuroendocrine (NET) Cancers
Your doctor might classify your NET as a grade according to the World Health Organization (WHO) grading system. Grading describes how tumour cells look under a microscope. It shows how abnormal the cells are and can give an idea of how quickly the tumour may develop. The grade is determined by both the mitotic count and Ki-67, which are markers of how fast the tumour cells grow and divide.
Identifying the grade of your NET helps you and your doctor create an appropriate treatment plan.
- Grade 1 (low-grade tumor): These cells divide at a low rate and therefore grow slowly.
- Grade 2 (intermediate-grade tumor): These cells divide at an intermediate rate.
- Grade 3 (high-grade tumor): These cells divide at a fast rate and therefore grow quickly.
NETs are also 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.
How are grades different to stages?
The grade focuses on how the tumour cells look under a microscope, as well as how they’re dividing and at what rate.
The stage of a NET describes its size and whether it has spread beyond its original site.
Your NET may fall under one of these stages:
- Localised: Be contained in a particular area of the body
- Regional: Have spread to nearby tissues or lymph nodes
- Metastatic: Have spread throughout the body
Both grades and stages tell your care team more about your NET cancer and which treatment may be most effective.
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