Table of ContentsView AllTable of ContentsTypesTNM Staging SystemPapillary (Follicular) StagingStage 4 CancerMedullary StagesAnaplastic StagingPrognosisNext in Thyroid Cancer GuideSymptoms of Thyroid Cancer
Table of ContentsView All
View All
Table of Contents
Types
TNM Staging System
Papillary (Follicular) Staging
Stage 4 Cancer
Medullary Stages
Anaplastic Staging
Prognosis
Next in Thyroid Cancer Guide
Read on to learn what you need to know about thyroid cancer stages, how to interpret number and letter combinations, why different staging systems are used, and survival rates for each of the four types of thyroid cancer.
LaylaBird / Getty Images
Types of Thyroid Cancer
Thyroid cancer has four main types, which are:
Stage 0 Cancer: What It MeansStage 0 cancer is also calledcarcinoma in situ(CIS), meaning thatprecancerous cellsthat look like cancer under a microscope—and may become cancerous in the future—exist in the original location in the thyroid gland. However, these cells haven’t yet developed into a thyroid carcinoma tumor.
Stage 0 Cancer: What It Means
Stage 0 cancer is also calledcarcinoma in situ(CIS), meaning thatprecancerous cellsthat look like cancer under a microscope—and may become cancerous in the future—exist in the original location in the thyroid gland. However, these cells haven’t yet developed into a thyroid carcinoma tumor.
The TNM Staging System
The American Joint Committee on Cancer/Union for International Cancer Control (AJCC/UICC) periodically updates the TNM staging system for thyroid cancer in the United States. In 2018, the AJCC/UICC introduced the current system.
The TNM staging system assigns a number after each letter to indicate the size of tumors and whether or not cancer has spread, as described in the table below:
A capital “X” suffix may also follow one of the TNM letters to indicate uncertainty. For example, MX would mean diagnosticians aren’t sure if the cancer has metastasized.
What Is the SEER Staging Program?
The Surveillance, Epidemiology, and End Results (SEER) program collects data and compiles cancer statistics in the United States. Unlike the TNM staging system, SEER summary staging doesn’t use numbers or letters to categorize different stages of thyroid cancer.Instead, SEER uses three common words (localized, regionalized, distant) for categorization:
Papillary or Follicular Thyroid Cancer Staging
Age makes a difference when staging papillary or follicular thyroid cancer. People under age 55 and those age 55 and older are categorized differently.
For Patients Under 55
For people under age 55, papillary and follicular thyroid cancer are only categorized as stages 1 or 2:
For Patients 55 and Older
For people 55 and older, papillary and follicular thyroid cancer are categorized as stages 1, 2, or 3:
Stage 4 Papillary, or Follicular, Thyroid Cancer
Stage 4 papillary, or follicular, thyroid cancer is metastatic, meaning that it’s spread outside the thyroid. When this happens, an uppercase letter (“A,” “B, or “C”) is placed after the “4” to indicate the extent of its spread:
Stages of Medullary Thyroid Cancer
Age does not play a role in determining the stages of medullary thyroid cancer. Stages 1, 2, 3, and 4 are used for staging this type regardless of whether someone is older or younger than 55:
Anaplastic Thyroid Cancer Staging
Anaplastic thyroid cancer is the least common but most deadly type. This type of cancer is automatically classified as stage 4 cancer because it grows incredibly fast and can spread to distant parts of the body really quickly. The letters “A,” “B,” and “C” after the “4” indicate where the cancer has spread:
What Is the Life Expectancy of Someone With Thyroid Cancer?
Undifferentiated (anaplastic) thyroid cancer has very high mortality rates and dramatically reduces life expectancy. The five-year relative survival rate for metastatic (stage 4) anaplastic thyroid cancer is only 4%, meaning that 96 out of 100 people will die prematurely from this type of thyroid cancer.
The average survival time for people diagnosed with undifferentiated anaplastic thyroid cancer is only six to eight months. However, life expectancy for other types of thyroid cancer is significantly better. For differentiated thyroid cancers, the 5-year survival rate for stages 1, 2, 3, and 4 are 100%, 100%, 93%, and 51% respectively.
Summary
Thyroid cancer has a high survival rate. Nine out of 10 people diagnosed with thyroid cancer won’t die from this disease. That said, survival rates depend on what type of thyroid cancer someone has and if it’s spread. Different stages of thyroid cancer are ranked on a scale from 1 to 4. Stage 4 thyroid cancer is the most serious. Stage 1 is the least severe. Generally, the lower the thyroid cancer stage number, the better the prognosis.
The TNM system is the most commonly used staging system. TNM assigns numbers after each letter to indicate the size of someone’s tumor, if there’s cancer in any lymph nodes, and how far it’s spread.
Another staging system, SEER, doesn’t use numbers; it uses three words—“localized,” “regionalized,” and “distant”—to indicate if the cancer has spread. Localized thyroid cancer is easier to treat and has a better survival rate than cancer that’s spread to distant parts of the body.
19 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
NIH: National Cancer Institute.Cancer staging.
NIH: National Cancer Institute.Thyroid cancer—patient version.
Ito Y, Miyauchi A, Kihara M, Fukushima M, Higashiyama T, Miya A.Overall survival of papillary thyroid carcinoma patients: a single‐institution long‐term follow‐up of 5897 patients.World j surg. 2018;42(3):615-622. doi:10.1007/s00268-018-4479-z
Park H, Yang H, Heo J, Kim TH, Kim SW, Chung JH.Long-term outcomes and causes of death among medullary thyroid carcinoma patients with distant metastases.Cancers. 2021;13(18):4670. doi:https://doi.org/10.3390/cancers13184670
Maniakas A, Dadu R, Busaidy NL, et al.Evaluation of overall survival in patients with anaplastic thyroid carcinoma, 2000-2019.JAMA Oncol. 2020;6(9):1397-1404. doi:10.1001/jamaoncol.2020.3362
Al-Qurayshi Z, Sullivan CB, Khadra H, Shama M, Lee GS, Kandil E.Presentation and outcomes of patients with undifferentiated thyroid carcinoma: a national perspective.Gland Surgery. 2021;10(6):1971979-1971979. doi:10.21037/gs-20-927
National Cancer Institute.SEER Training: Code 0: In Situ.
Asare EA, Grubbs EG, Gershenwald JE, Greene FL, Aloia TA.Setting the “stage” for surgical oncology fellows: pierre denoix and TNM staging.Journal of Surgical Oncology. 2019;119(7):823-823. doi:10.1002/jso.25404
Casella C, Ministrini S, Galani A, Mastriale F, Cappelli C, Portolani N.The new TNM staging system for thyroid cancer and the risk of disease downstaging.Front Endocrinol. 2018;9:541.doi:10.3389/fendo.2018.00541
Brierley J, O’Sullivan B, Asamura H, et al.Global Consultation on Cancer Staging: promoting consistent understanding and use.Nat Rev Clin Oncol. 2019;16(12):763-771. doi:10.1038/s41571-019-0253-x
The Surveillance, Epidemiology, and End Results (SEER).Cancer stat facts: Cancer of any site.
NIH: National Cancer Institute.SEER program coding and staging manual 2023.
American Cancer Society.Thyroid cancer stages.
Bible KC, Kebebew E, Brierley J, et al.2021 American Thyroid Association guidelines for management of patients with anaplastic thyroid cancer: american thyroid association anaplastic thyroid cancer guidelines task force.Thyroid. 2021;31(3):337-386.
Boucai L, Zafereo M, Cabanillas ME.Thyroid cancer: a review.JAMA. 2024;331(5):425. doi:10.1001/jama.2023.26348
Lauretta R, Bianchini M, Mormando M, Puliani G, Appetecchia M.Focus on thyroid cancer in elderly patients.Endocrines. 2023;4(4):757-772. doi:10.3390/endocrines4040055
Liu TR, Xiao ZW, Xu HN, et al.Treatment and prognosis of anaplastic thyroid carcinoma: a clinical study of 50 cases. Zhou S, ed.PLoS ONE. 2016;11(10):e0164840. doi:10.1371/journal.pone.0164840
Ganly I, Nixon IJ, Wang LY, et al.Survival from differentiated thyroid cancer: what has age got to do with it?Thyroid. 2015;25(10):1106-1114. doi:10.1089/thy.2015.0104
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
Spotting, Diagnosing, and Treating Thyroid CancerWhat Are the Stages of Thyroid Cancer?What Are the Symptoms of Thyroid Cancer?Signs Thyroid Cancer Spread to Lymph Nodes, Bones, ElsewhereThyroid Cancer Facts and Statistics
Spotting, Diagnosing, and Treating Thyroid Cancer
What Are the Stages of Thyroid Cancer?
What Are the Symptoms of Thyroid Cancer?
Signs Thyroid Cancer Spread to Lymph Nodes, Bones, Elsewhere
Thyroid Cancer Facts and Statistics
By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.Cookies SettingsAccept All Cookies
By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.
Cookies SettingsAccept All Cookies
