# Follicular thyroid cancer

Source: https://onco.cc/cancers/follicular-thyroid-cancer/  
OnCo record `follicular-thyroid-cancer` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Follicular thyroid cancer looks like a benign nodule on a needle biopsy, so the diagnosis is usually made only after surgery. It spreads through the bloodstream rather than to neck nodes, is treated like papillary cancer with surgery and radioactive iodine, and has a good outlook when caught early.

## Summary

Follicular thyroid cancer is separated from a benign follicular adenoma only by invasion of the capsule or blood vessels, which a fine-needle biopsy cannot show; a follicular result on biopsy therefore leads to diagnostic lobectomy, and molecular tests on the aspirate now help decide who needs it. RAS mutations and the PAX8-PPARG fusion are common, and TERT promoter mutations mark aggressive disease. Minimally invasive tumours are cured by lobectomy; widely invasive tumours receive total thyroidectomy and radioactive iodine, which also treats the lung and bone metastases the disease favours. Oncocytic (Hurthle cell) carcinoma, once a follicular variant, is a separate entity in the 2022 WHO classification and takes up iodine poorly. Iodine-refractory disease is treated as in papillary cancer with lenvatinib or sorafenib.

## Fields

- Kind: Cancer
- Last checked: 2026-09-17
- Also known as: Follicular thyroid carcinoma; FTC; Oncocytic (Hurthle cell) carcinoma
- Tags: subtype-page
- Group: endocrine
- Burden: About one in ten thyroid cancers, commoner where iodine is scarce; it spreads through the blood to bone and lung rather than to neck nodes, and survival is somewhat lower than for papillary cancer but still high.
- Subtypes: Minimally invasive (capsular invasion only); Encapsulated angioinvasive; Widely invasive; Oncocytic (Hurthle cell) carcinoma (separate entity since WHO 2022)
- Biomarkers: RAS mutations; PAX8-PPARG fusion; TERT promoter mutation; Molecular tests on indeterminate aspirates (Afirma, ThyroSeq); Thyroglobulin

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/follicular-thyroid-cancer/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/follicular-thyroid-cancer/#overview [3 state-of-the-art points]
- Types and stages (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/follicular-thyroid-cancer/#what-it-is [4 subtypes]
- Symptoms and diagnosis (on the hub): How this cancer shows itself, how the diagnosis is confirmed, and the biomarkers clinicians test for. https://onco.cc/cancers/follicular-thyroid-cancer/#finding-it [5 biomarkers]
- Treatment (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/follicular-thyroid-cancer/#treating-it [4 settings, 2 decisions with options]
- Trials and papers (on the hub): Trials recruiting now, the landmark trials, the trials held by this cancer's subtypes, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/follicular-thyroid-cancer/#evidence [3 key papers, 3 milestones]
- Biology and targets (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/follicular-thyroid-cancer/#science [5 targets]
- Countries and centres (own page): Cases by country, the UK and NHS pathway and other country lenses, the expert centres with trials on record, and the centres named on this cancer's subtypes. https://onco.cc/cancers/follicular-thyroid-cancer/where-you-are/
- Decisions and support (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/follicular-thyroid-cancer/#living-with-it [14 questions, 6 red cards]
- Pipeline and open problems (own page): Everything in development, the medicines held by this cancer's subtypes, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/follicular-thyroid-cancer/coming/ [3 medicines, 3 open problems]
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/follicular-thyroid-cancer/data/ [23 connected records]

## Standard of care

- Indeterminate follicular nodule: Molecular testing of the aspirate; diagnostic lobectomy when suspicious. ([Thyroid cancer](https://onco.cc/cancers/thyroid/))
- Minimally invasive: Lobectomy alone in most cases; completion surgery and iodine only for high-risk features. ([Thyroid cancer](https://onco.cc/cancers/thyroid/))
- Widely invasive or metastatic: Total thyroidectomy, radioactive iodine, TSH suppression; bone metastases may need surgery or radiotherapy. ([Radioiodine therapy and whole-body iodine scanning](https://onco.cc/technologies/radioiodine-therapy/), [Palliative radiotherapy](https://onco.cc/technologies/palliative-radiotherapy/))
- Iodine-refractory: Lenvatinib or sorafenib; clinical trials of redifferentiation. ([Lenvatinib](https://onco.cc/drugs/lenvatinib/), [Sorafenib](https://onco.cc/drugs/sorafenib/), [Radioiodine-refractory (RAI-R) thyroid cancer](https://onco.cc/terms/rai-refractory/))

## State of the art

- Molecular testing of indeterminate nodules spares many patients a diagnostic operation.
- Most follicular cancers are cured by surgery alone; the widely invasive minority drives the deaths.
- Oncocytic carcinoma's separation as its own entity reflects its distinct genetics and poor iodine avidity.

## Open problems

- Telling adenoma from carcinoma without surgery.
- Bone metastases respond poorly to iodine.
- Few trials specific to follicular histology.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Follicular_thyroid_cancer
- Wikipedia: https://en.wikipedia.org/wiki/Follicular_thyroid_cancer

## Connected records

- cancers: [Anaplastic thyroid cancer](https://onco.cc/cancers/anaplastic-thyroid-cancer/), [Medullary thyroid cancer](https://onco.cc/cancers/medullary-thyroid-cancer/), [Papillary thyroid cancer](https://onco.cc/cancers/papillary-thyroid-cancer/), [Thyroid cancer](https://onco.cc/cancers/thyroid/)
- key papers: [2015 American Thyroid Association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer](https://onco.cc/key-papers/paper-ata-2015-thyroid-nodules-dtc-haugen-thyroid-2016/), [DECISION: sorafenib in radioactive iodine-refractory differentiated thyroid cancer](https://onco.cc/key-papers/paper-decision-sorafenib-lancet-2014/), [SELECT: lenvatinib versus placebo in radioiodine-refractory differentiated thyroid cancer](https://onco.cc/key-papers/paper-select-lenvatinib-nejm-2015/)
- technologies: [Palliative radiotherapy](https://onco.cc/technologies/palliative-radiotherapy/), [Radioiodine therapy and whole-body iodine scanning](https://onco.cc/technologies/radioiodine-therapy/), [Thyroglobulin, calcitonin and CEA in thyroid cancer follow-up](https://onco.cc/technologies/thyroid-cancer-markers/)
- drugs: [Dabrafenib](https://onco.cc/drugs/dabrafenib/), [Lenvatinib](https://onco.cc/drugs/lenvatinib/), [Sorafenib](https://onco.cc/drugs/sorafenib/)
- terms: [Radioiodine-refractory (RAI-R) thyroid cancer](https://onco.cc/terms/rai-refractory/)
- people: [Bryan R. Haugen](https://onco.cc/people/bryan-haugen/)

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JSON: https://onco.cc/api/v1/entities/follicular-thyroid-cancer.json