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What is thyroid cancer?

Thyroid cancer develops when the cells of the thyroid grow and divide in an abnormal way. There are several types of thyroid cancer. It is possible to have more than one type at once, although this is unusual.

More common types of thyroid cancer

  • Papillary
    • most common type (about 70-80% of all thyroid cases)
    • develops from the follicular cells
    • tends to grow slowly
  • Follicular
    • about 15–20% of all thyroid cancer cases
    • develops from the follicular cells
    • includes Hürthle cell carcinoma, a less common subtype

Rare types of thyroid cancer

  • Medullary
    • about 4% of all thyroid cancer cases
    • develops from the parafollicular cells (C-cells)
    • can run in families
    • may be associated with tumours in other glands
  • Anaplastic
    • a rare thyroid cancer (about 1% of all thyroid cancer cases)
    • may develop from papillary or follicular thyroid cancer
    • tends to grow quickly
    • usually occurs in people over 60

How common is thyroid cancer?

About 2900 people are diagnosed with thyroid cancer each year in Australia. Thyroid cancer can occur at any age. It affects almost three times as many women as men – it is the seventh most common cancer affecting Australian women of all ages, and the most common cancer diagnosed in women aged 20–24.

Diagnoses of thyroid cancer in Australia have increased in recent years, with almost four times as many cases estimated in 2019 as there were in 1982. Some of this increase is due to the improved quality and greater use of diagnostic scans, such as ultrasounds. This has led to the detection of smaller, often insignificant, thyroid cancers that would otherwise not have been found. Researchers are trying to work out if there are any other causes of the increased rates of thyroid cancer.

Featured resource

Understanding Thyroid Cancer

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This information is reviewed by

This information was last reviewed January 2020 by the following expert content reviewers: A/Prof Diana Learoyd, Endocrinologist, Northern Cancer Institute, and Northern Clinical School, The University of Sydney, NSW; Dr Gabrielle Cehic, Nuclear Medicine Physician and Oncologist, South Australia Medical Imaging (SAMI), and Senior Staff Specialist, The Queen Elizabeth Hospital, SA; Dr Kiernan Hughes, Endocrinologist, Northern Endocrine and St Vincents Hospital, NSW; Yvonne King, 13 11 20 Consultant, Cancer Council NSW; Dr Christine Lai, Senior Consultant Surgeon, Breast and Endocrine Surgical Unit, The Queen Elizabeth Hospital, and Senior Lecturer, Discipline of Surgery, University of Adelaide, SA; A/Prof Nat Lenzo, Nuclear Physician and Specialist in Internal Medicine, Group Clinical Director, GenesisCare Theranostics, and The University of Western Australia, WA; Ilona Lillington, Clinical Nurse Consultant (Thyroid and Brachytherapy), Cancer Care Services, Royal Brisbane Women’s Hospital, QLD; Jonathan Park, Consumer.