Health condition
Medullary thyroid cancer
Medullary thyroid cancer arises from the thyroid’s calcitonin-producing C cells; a quarter of cases are inherited through RET mutations, calcitonin provides an exquisitely sensitive tumour marker, and selective RET inhibitors now treat advanced disease.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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Every diagnosis warrants RET genetic testing - inherited cases affect whole families
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Calcitonin and CEA blood levels track the disease with unusual precision
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Complete surgery - total thyroidectomy with node dissection - is the primary treatment
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Selpercatinib and other RET inhibitors have transformed advanced RET-driven disease
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
This cancer differs from common thyroid cancers at every level: it arises from neuroendocrine C cells, does not take up radioactive iodine, secretes measurable calcitonin from its earliest stages, and in about 25% of patients reflects an inherited RET mutation - multiple endocrine neoplasia type 2 - which also brings phaeochromocytoma risk that must be excluded before any operation. A thyroid nodule with raised calcitonin reorders the entire diagnostic pathway.
Diagnosis and treatment routes
Surgery carries the curative burden, and its completeness matters because no radioiodine safety-net exists; calcitonin afterwards tells the truth about residual disease with little ambiguity, and its doubling time forecasts behaviour. For progressive advanced disease, highly selective RET inhibitors achieve deep, durable responses in mutation-positive patients - among precision oncology’s clearest wins. Family cascade testing, with risk-adapted preventive thyroidectomy in childhood for carriers, closes the loop. If you are waiting for results or want a second opinion on a proposed plan, a private consultation with a specialist who treats this condition regularly can usually be arranged quickly, and most will review your existing scans, biopsy reports and MDT correspondence.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a consultant endocrine surgeon. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Medullary thyroid cancer.
Quick, plain-English answers to what people ask us most.
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What is medullary thyroid cancer?
Medullary thyroid cancer is a less common type of thyroid cancer arising from specific hormone-producing cells (C-cells) within the thyroid gland, distinct from the more common papillary and follicular thyroid cancers. It can occur sporadically or as part of an inherited genetic syndrome.
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What causes medullary thyroid cancer?
Around a quarter of cases are linked to an inherited genetic mutation, most commonly in the RET gene, as part of multiple endocrine neoplasia type 2 syndrome, while the remainder occur sporadically without a clear inherited cause. Genetic testing is recommended for everyone diagnosed with this cancer type, given the significant proportion of inherited cases.
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What are the symptoms of medullary thyroid cancer?
Symptoms can include a thyroid lump or nodule, swollen lymph nodes in the neck, and sometimes symptoms related to excess hormone production such as diarrhoea or flushing, since this cancer type can produce specific hormones. Many cases are found through investigation of a thyroid nodule found incidentally.
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Is medullary thyroid cancer dangerous?
Yes, it can spread to lymph nodes and other organs, and inherited forms can be more aggressive, particularly in certain genetic subtypes, making thorough treatment and monitoring important. Early diagnosis and complete surgical removal give the best chance of good long-term outcomes.
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Is medullary thyroid cancer genetic?
In about a quarter of cases, yes, it's linked to an inherited RET gene mutation as part of multiple endocrine neoplasia type 2 syndrome, which also carries risk of other endocrine tumours. Genetic testing is recommended for all patients diagnosed with this cancer, since identifying an inherited cause has important implications for family members and future monitoring.
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Can medullary thyroid cancer be cured?
Complete surgical removal, particularly when the cancer is caught at an early stage, offers a good chance of cure, though this cancer type can be harder to treat if it has already spread by the time of diagnosis. Regular monitoring after treatment, using a specific blood marker, helps detect any recurrence early.
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How is medullary thyroid cancer treated?
Treatment primarily involves surgical removal of the thyroid gland, often along with nearby lymph nodes if there's evidence of spread, since this cancer type doesn't respond to radioactive iodine treatment used for other thyroid cancers. Targeted medications are available for advanced or spreading disease that can't be fully treated with surgery alone.
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How is medullary thyroid cancer monitored after treatment?
Monitoring typically uses a specific blood marker (calcitonin) that's produced by these cancer cells, allowing sensitive detection of any residual or recurrent disease, alongside regular clinical review and imaging as needed. This specific marker is a particularly useful tool for long-term follow-up in this cancer type.
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Medullary thyroid cancer vs papillary thyroid cancer — what's the difference?
Medullary thyroid cancer arises from different cells (C-cells) than papillary thyroid cancer (which arises from the hormone-producing follicular cells), doesn't respond to radioactive iodine treatment, and has a significant inherited genetic component in a substantial minority of cases, unlike papillary cancer. These differences significantly affect treatment approach, monitoring, and the importance of genetic testing and family screening.
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When should I see a specialist about medullary thyroid cancer, and how quickly can I be seen privately?
A thyroid nodule, especially with a family history of thyroid or endocrine cancers, should prompt endocrinology assessment. Private endocrinology consultations can typically be arranged within about two weeks, considerably faster than standard NHS routes, though urgent NHS cancer pathways also exist for suspicious findings.