What are the grades and stages of thyroid cancer?

Cancer grading diagram

What are the grades of thyroid cancer?

Grading describes how quickly the cancer may grow and spread. 

  • Low-grade thyroid cancer: The cancer cells look only slightly abnormal, much like normal thyroid cells. The cancer is usually slow-growing and less likely to spread than high-grade thyroid cancer.
  • High-grade thyroid cancer: The cancer cells look fairly or very abnormal and are more likely to grow quickly.

Grading describes the cancer cells – what they look like and how they might grow. Staging describes where the cancer is in your body.

What are the stages of thyroid cancer?

Staging means finding out how big the cancer is and if it has spread to other parts of your body. Staging will help your doctor to plan the best treatment for you.

The staging system normally used in thyroid cancer is called TNM. This stands for:

  • Tumour (T): How big is the tumour?
  • Node (N): Is there cancer in your lymph nodes?
  • Metastasis (M): Has the cancer has spread to other parts of your body?

Your doctor often uses this information to give your cancer a number stage – from 1 to 4.

A higher number, such as stage 4, means a more serious cancer. Some stages are further divided into stage A and B. 

The different types of thyroid cancer can have different stage numbers, depending on your age, or they may omit certain stages. For example, there is no stage 2 or 3 for papillary or follicular cancer in people under 45.

Stage 2 thyroid cancer diagram

Staging can be hard to understand, so ask your doctor and nurse for more information if you need it.

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