What is thyroid cancer?

Thyroid cancer is malignancy of the thyroid gland — a butterfly-shaped endocrine gland in the neck. Most are well-differentiated and highly treatable; a minority are aggressive and poorly responsive to treatment. The 5-fold rise in thyroid cancer incidence over 30 years is partly real (radiation exposure, iodine deficiency, obesity links) but substantially due to overdiagnosis — detection of small indolent papillary cancers on neck ultrasound that would never have caused clinical problems.

What are the different types of thyroid cancer?

Papillary thyroid carcinoma (>85%): most common, excellent prognosis (>95% 10-year survival), often lymph node metastases (not life-threatening in most), BRAF V600E mutation in approximately 60%. Follicular thyroid carcinoma (~10%): metastasises haematogenously (to bone, lung); RAI-responsive; good prognosis in most. Medullary thyroid carcinoma (~3%): from C-cells; calcitonin marker; 25% hereditary (RET mutations); not RAI-responsive. Anaplastic thyroid carcinoma (<2%): undifferentiated, extremely aggressive, median survival 3-5 months — an oncological emergency.

How is thyroid cancer treated?

Differentiated thyroid cancer (papillary/follicular): total thyroidectomy (or lobectomy for very low-risk); RAI (I-131) ablation for intermediate/high-risk disease; levothyroxine to suppress TSH (promotes cancer growth); lifelong thyroglobulin monitoring. Medullary thyroid cancer: total thyroidectomy + central neck dissection; kinase inhibitors (vandetanib, cabozantinib) for progressive disease. Anaplastic thyroid cancer: multimodal approach — surgery if resectable, external beam radiation, chemotherapy; dabrafenib + trametinib if BRAF V600E mutated (achieves response in approximately 60-70%).

What is overdiagnosis and the thyroid cancer epidemic?

The dramatic 5-fold rise in thyroid cancer incidence over 30 years is substantially driven by overdiagnosis — detection of small papillary microcarcinomas (≤1cm) that would never have caused symptoms or death. When South Korea implemented a national thyroid ultrasound screening programme in the 1990s, thyroid cancer diagnoses increased 15-fold — with no reduction in thyroid cancer deaths. Most thyroid microcarcinomas are indolent and can be safely monitored with active surveillance rather than immediate surgery. ATA guidelines now support observation for low-risk microcarcinomas.

Who should be tested for hereditary thyroid cancer?

All patients with medullary thyroid cancer should undergo germline RET mutation testing — approximately 25% have a hereditary mutation (MEN2A, MEN2B or familial MTC). Identifying RET mutations is critical because: first-degree relatives should be tested and — if RET-positive — offered prophylactic thyroidectomy at the appropriate age (determined by specific mutation). RET M918T mutation (MEN2B) requires thyroidectomy in the first 6 months of life; other mutations allow later surgery.

Can thyroid cancer be prevented?

Radiation exposure prevention: childhood exposure to ionising radiation (medical or fallout) dramatically increases thyroid cancer risk — iodine-131 supplementation after nuclear accidents protects the thyroid by saturating the gland. Iodine sufficiency: iodine deficiency promotes follicular thyroid cancer; universal salt iodisation has been a major preventive public health measure. Prophylactic thyroidectomy: in hereditary MTC (germline RET mutations), thyroidectomy before cancer develops is curative.

How does GMJ News cover thyroid cancer?

GMJ News covers GLOBOCAN thyroid cancer data, the overdiagnosis controversy, RAI treatment evidence, medullary thyroid cancer RET mutations, anaplastic thyroid cancer management and radiation-related thyroid cancer. Thyroid cancer is a significant clinical and public health concern in Georgia — an iodine-historically-deficient region — relevant to PHIG's cancer programme and the Georgian Medical Journal.

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Thyroid Cancer

Q: How is thyroid cancer treated?

Differentiated thyroid cancer (papillary/follicular): total thyroidectomy (or lobectomy for very low-risk); RAI (I-131) ablation for intermediate/high-risk disease; levothyroxine to suppress TSH (promotes cancer growth); lifelong thyroglobulin monitoring. Medullary thyroid cancer: total thyroidectomy + central neck dissection; kinase inhibitors (vandetanib, cabozantinib) for progressive disease. Anaplastic thyroid cancer: multimodal approach — surgery if resectable, external beam radiation, chemotherapy; dabrafenib + trametinib if BRAF V600E mutated (achieves response in approximately 60-70%).

Q: What is overdiagnosis and the thyroid cancer epidemic?

The dramatic 5-fold rise in thyroid cancer incidence over 30 years is substantially driven by overdiagnosis — detection of small papillary microcarcinomas (≤1cm) that would never have caused symptoms or death. When South Korea implemented a national thyroid ultrasound screening programme in the 1990s, thyroid cancer diagnoses increased 15-fold — with no reduction in thyroid cancer deaths. Most thyroid microcarcinomas are indolent and can be safely monitored with active surveillance rather than immediate surgery. ATA guidelines now support observation for low-risk microcarcinomas.

Q: Who should be tested for hereditary thyroid cancer?

All patients with medullary thyroid cancer should undergo germline RET mutation testing — approximately 25% have a hereditary mutation (MEN2A, MEN2B or familial MTC). Identifying RET mutations is critical because: first-degree relatives should be tested and — if RET-positive — offered prophylactic thyroidectomy at the appropriate age (determined by specific mutation). RET M918T mutation (MEN2B) requires thyroidectomy in the first 6 months of life; other mutations allow later surgery.

Q: Can thyroid cancer be prevented?

Radiation exposure prevention: childhood exposure to ionising radiation (medical or fallout) dramatically increases thyroid cancer risk — iodine-131 supplementation after nuclear accidents protects the thyroid by saturating the gland. Iodine sufficiency: iodine deficiency promotes follicular thyroid cancer; universal salt iodisation has been a major preventive public health measure. Prophylactic thyroidectomy: in hereditary MTC (germline RET mutations), thyroidectomy before cancer develops is curative.

Q: How does GMJ News cover thyroid cancer?

GMJ News covers GLOBOCAN thyroid cancer data, the overdiagnosis controversy, RAI treatment evidence, medullary thyroid cancer RET mutations, anaplastic thyroid cancer management and radiation-related thyroid cancer. Thyroid cancer is a significant clinical and public health concern in Georgia — an iodine-historically-deficient region — relevant to PHIG's cancer programme and the Georgian Medical Journal.

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Thyroid cancer — with 586,202 new cases in 2020 — is the most rapidly rising cancer incidence of any major malignancy, though this rise is partially attributable to overdiagnosis of small indolent papillary cancers detected incidentally on ultrasound (IARC GLOBOCAN 2020). Over 85% of thyroid cancers are papillary carcinoma — with an excellent prognosis (10-year survival >95%) when treated with surgery, radioactive iodine and TSH suppression. The minority of cases — medullary (RET mutations, MEN2) and anaplastic thyroid carcinoma (universally fatal, median survival 3-5 months without treatment) — represent the most challenging ends of the thyroid cancer spectrum.

Key messages

586K cases — fastest rising cancer incidence

Thyroid cancer has the fastest rising incidence of any major cancer over 30 years — from approximately 120,000 new cases in 1990 to 586,202 in 2020. A substantial proportion of this rise reflects overdiagnosis of small incidental papillary cancers detected on ultrasound (IARC GLOBOCAN 2020).

Over 85% are papillary — excellent prognosis

Papillary thyroid carcinoma (PTC) comprises over 85% of thyroid cancers, with a 10-year survival exceeding 95% when properly treated. PTC is largely a curable cancer.

Four types — vastly different biology

Four main types: papillary (>85% — slow-growing, curable); follicular (~10% — haematogenous spread, RAI-responsive); medullary (~3% — calcitonin-secreting, RET mutations, MEN2 syndromes); anaplastic (<2% — universally fatal, median survival 3-5 months).

Radioactive iodine — unique treatment

Differentiated thyroid cancers (papillary, follicular) are treated with thyroidectomy followed by radioactive iodine (RAI/I-131) ablation — exploiting thyroid cells' unique ability to concentrate iodine. TSH suppression with levothyroxine completes treatment.

RET mutations drive medullary cancer

Medullary thyroid cancer (MTC) arises from parafollicular C-cells. Approximately 25% are hereditary — caused by germline RET mutations (MEN2A, MEN2B, familial MTC). Vandetanib and cabozantinib are approved for progressive MTC. Prophylactic thyroidectomy in RET mutation carriers prevents MTC.

Anaplastic — an emergency

Anaplastic thyroid carcinoma (ATC) — universally fatal, median survival 3-5 months — requires immediate specialist evaluation. The BRAFV600E mutation is present in approximately 40-50%; dabrafenib + trametinib (BRAF/MEK inhibitors) achieves responses in BRAF-mutated ATC and has transformed a once-untreatable emergency.

Key statistics

586K

new thyroid cancer cases/year (2020)

IARC GLOBOCAN

>95%

10-year survival for papillary thyroid cancer

ESMO/ATA

increase in thyroid cancer incidence over 30 years

IARC

3-5mth

median survival for anaplastic thyroid cancer without treatment

ESMO

~25%

of MTC cases are hereditary (RET mutations)

ESMO

3:1

female to male ratio in thyroid cancer

IARC

Thyroid cancer types by frequency and 10-year survival — ATA/ESMO

Source: ATA/ESMO. Papillary dominates incidence but has excellent prognosis; anaplastic is rare but invariably fatal.

Glossary of key terms

Papillary thyroid carcinoma (PTC)
ATA/ESMOThe most common thyroid cancer — slow-growing, often multifocal, with lymph node metastases common but rarely life-threatening. BRAF V600E mutation in approximately 60%. Treated with thyroidectomy (total or lobectomy for low-risk), RAI ablation for higher-risk disease, and TSH suppression.

Radioactive iodine (RAI/I-131)
ATA/WHORadioactive iodine-131 — taken orally — is concentrated by remnant thyroid tissue and metastases, delivering targeted radiation. Used for post-surgical thyroid remnant ablation and treatment of RAI-avid metastases. The unique ability of thyroid cells to take up iodine makes RAI one of the most targeted cancer treatments in medicine.

Medullary thyroid carcinoma (MTC)
ATA/ESMOArises from parafollicular C-cells — not thyroid follicular cells. Produces calcitonin (the tumour marker). Approximately 25% are hereditary — RET germline mutations in MEN2A (pheochromocytoma + primary hyperparathyroidism), MEN2B (pheochromocytoma + marfanoid habitus, mucosal neuromas), or familial MTC. Treated with total thyroidectomy; no RAI response; kinase inhibitors for progressive/metastatic disease.

Vandetanib and cabozantinib
FDA/ESMOKinase inhibitors approved for progressive/symptomatic metastatic MTC: vandetanib (targets RET, VEGFR, EGFR — FDA 2011); cabozantinib (RET, VEGFR2, MET — FDA 2012 for progressive MTC; 2019 for radioiodine-refractory DTC). Both approved for unresectable locally advanced or metastatic MTC.

Lenvatinib and sorafenib
FDA/EMAMulti-kinase inhibitors approved for radioiodine-refractory differentiated thyroid cancer (DTC — papillary/follicular not responsive to RAI, with progressive disease): lenvatinib (targets VEGFR 1-3, FGFR, PDGFR, RET, KIT — SELECT trial); sorafenib (targets VEGFR, BRAF — DECISION trial). Both extend PFS in RAI-refractory DTC.

Overdiagnosis controversy
IARC/ATAThe dramatic rise in thyroid cancer incidence is partly (largely, in some countries) due to overdiagnosis — detection of small papillary cancers (<1cm — papillary microcarcinomas) that would never have caused symptoms or death. South Korea's universal thyroid ultrasound screening programme caused a 15-fold increase in thyroid cancer diagnoses with no reduction in thyroid cancer deaths. Active surveillance (watchful waiting without immediate surgery) for low-risk microcarcinomas is increasingly recommended.