What is staging of medullary thyroid cancer?

The stage of a cancer describes its size and whether it has spread from where it started.

Different types of thyroid cancer are staged differently. This information is about staging medullary thyroid cancer.

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TNM staging

The most common staging system is the TNM system.

T describes the size of the tumour and whether it has spread into nearby tissues around the thyroid gland.

N describes whether the cancer has spread to the lymph nodes close to the thyroid gland.

M describes whether the cancer has spread to other parts of the body, such as the lungs or the bones (metastatic).

T – Tumour

Doctors put a number next to the T to describe the size and spread of the cancer.

T1 means the tumour is 2cm or less and has not grown outside the thyroid gland.

  • T1a means the tumour is 1cm or smaller.
  • T1b means the tumour is between 1cm and 2cm.

T2 means the tumour is between 2cm and 4cm. It has not grown outside the thyroid gland.

T3 means the tumour is bigger than 4cm or it has grown slightly outside the thyroid gland.

  • T3a means the tumour is bigger than 4cm and has not grown outside the thyroid gland.
  • T3b means the tumour is of any size and has grown slightly outside the thyroid gland to nearby muscles.

T4 means the tumour has grown outside the thyroid gland and is attached to nearby structures.

  • T4a means the tumour has started to grow into nearby structures, such as the voicebox (larynx), windpipe (trachea), gullet (oesophagus) or the voicebox nerve (recurrent laryngeal nerve).
  • T4b means the tumour has grown into the area close to the spine or into a major blood vessel in the neck or upper chest.

N – Nodes

The N may have a number written next to it. This gives information about the nodes that were examined.

N0 means the lymph nodes are not affected.

N1 means the cancer has spread to lymph nodes close to the thyroid gland or in the neck or chest area.

  • N1a means the cancer has spread to lymph nodes in the middle of the neck, close to the thyroid gland.
  • N1b means the cancer has spread to lymph nodes in one or both sides of the neck or the upper part of the chest.

M – Metastases

The M may have a number written next to it. This gives information about whether the cancer has spread.

M0 means the cancer has not spread to other parts of the body.

M1 means the cancer has spread to another part of the body.

Number staging

Doctors often use the information from the TNM system to make an overall number stage, from 1 to 4.

Stage 1

The tumour is no bigger than 2cm. It has not grown outside the thyroid gland and not spread to any nearby lymph nodes.

Stage 2

The tumour is between 2cm and 4cm. It has not grown outside the thyroid gland. The cancer has not spread to nearby lymph nodes.

Or, the tumour is bigger than 4cm. It may have grown slightly outside the thyroid gland to nearby muscles in the neck. The cancer has not spread to nearby lymph nodes or other parts of the body.

Stage 3

The tumour is any size and it may or may not have grown slightly outside the thyroid gland to nearby muscles in the neck. The cancer has spread to nearby lymph nodes in the middle of the neck or upper chest. It has not spread to other parts of the body.

Stage 4

Stage 4 is divided into three groups, from A to C:

Stage 4A

The tumour is any size or has grown slightly outside the thyroid gland to nearby muscles in the neck. It has spread to lymph nodes in the side or sides of the neck or top of the chest. It has not spread to other parts of the body

Or, the tumour has started to grow into nearby structures, such as the voicebox (larynx), windpipe (trachea) or gullet (oesophagus). It may or may not have spread to nearby lymph nodes. It has not spread to other parts of the body.

Stage 4B

The tumour has grown into the area close to the spine, or into a large blood vessel in the neck or upper chest. It may or may not have spread the lymph nodes. It has not spread to other parts of the body.

Stage 4C

The tumour is any size and the cancer may or may not have spread to lymph nodes. It has spread to other parts of the body, such as the lungs or the bones.

About our information

  • References

    Below is a sample of the sources used in our thyroid cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    British Medical Journal. Best Practice Guidelines, Thyroid cancer. 2020.

    European Society Medical Oncology (ESMO): Thyroid cancer, Clinical Practice Guidelines for Diagnosis, Treatment and Follow-up. 2019.

    National Institute for Health and Care Excellence (NICE). TA535: Lenvatinib and Sorafenib for treating differentiated thyroid cancer after radioactive iodine. 2018. www.nice.org.uk/guidance/ta535 [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, Professor Nick Reed, Consultant Clinical 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.

The language we use

We want everyone affected by cancer to feel our information is written for them.

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