Thyroid cancer (thyroid carcinoma) is a malignant growth of the thyroid gland. The vast majority of thyroid nodules are benign — thyroid cancer makes up only a small share of all nodules.¹
The good news: the most common forms of thyroid cancer (papillary and follicular) have a very good prognosis. With early diagnosis and guideline-based treatment, they are usually highly curable. The S3 guideline on thyroid carcinoma (German Guideline Program in Oncology, version 1.0, July 2025) provides, for the first time in Germany, a comprehensive, evidence-based basis for diagnosis, treatment and follow-up.¹,²
Thyroid cancer is among the cancers with the best prognosis
Papillary and follicular carcinomas in particular are usually highly curable with early diagnosis and guideline-based treatment.¹
2. Forms
Thyroid carcinomas are classified by their tissue of origin and their behaviour.¹
Differentiated carcinomas (common, good prognosis)
Papillary carcinoma
By far the most common form. Usually grows slowly. Tends to metastasize to the neck lymph nodes. Prognosis usually very good.
Follicular carcinoma
Rarer than papillary carcinoma. Can metastasize via the bloodstream to the lungs and bones. Prognosis usually good.
Oncocytic carcinoma
Formerly classified as a variant of follicular carcinoma; since the WHO classification 2022 it is a distinct entity.
Other forms
Medullary carcinoma (MTC)
Arises from the C cells of the thyroid (calcitonin-producing cells). Can occur sporadically or hereditarily (MEN 2 syndrome). Calcitonin in the blood is an important tumour marker.
Anaplastic carcinoma
Very rare, but aggressive. Grows quickly and usually responds poorly to conventional therapies. Unfavourable prognosis. New targeted therapies (BRAF/MEK inhibitors) can help in certain cases.
Poorly differentiated carcinoma (PDTC)
In terms of aggressiveness, it sits between the differentiated and the anaplastic carcinoma.
3. Symptoms
In early stages, thyroid cancer usually causes no symptoms. It is mostly discovered as an incidental finding when thyroid nodules are evaluated. Possible later signs:
A palpable or visible lump in the neck
Rapid growth of a known nodule
Hoarseness — can indicate involvement of the recurrent laryngeal nerve
Trouble swallowing or a feeling of pressure in the neck
Enlarged neck lymph nodes
Back pain or bone pain — with distant metastases (rare at first diagnosis)
Warning signs for prompt evaluation
A rapidly growing, hard lump in the neck and/or newly appearing hoarseness without an obvious cause should be evaluated promptly by a doctor.
4. Risk factors
Radiation exposure: particularly radiation to the neck area in childhood (e.g. for other cancers) or radiation accidents. The most important known risk factor.
Family history: medullary carcinoma can occur hereditarily (MEN 2 syndrome, RET mutation). With differentiated carcinomas, familial clustering is rarer but possible.
Pre-existing thyroid conditions: goitre (an enlarged thyroid) and nodule formation can slightly increase the risk.
Sex and age: women are affected more often. The age at onset is usually between 30 and 60 years.
Iodine deficiency: can increase the risk of follicular carcinomas.
5. Diagnosis
Evaluating suspicious thyroid nodules is the most common route to diagnosis.¹
Ultrasound: assesses the size, shape, echogenicity, margins and blood flow of the nodule. A standardized risk classification (e.g. EU-TIRADS) helps with categorization.
Fine-needle aspiration (FNA): taking cells from the nodule under ultrasound guidance. The cytological assessment (e.g. by the Bethesda classification) determines the further approach.
Scintigraphy: shows whether a nodule is hormonally active (hot) or not (cold). Cold nodules have a slightly increased risk of malignancy.
Calcitonin: measured in the blood. An elevated value can indicate a medullary carcinoma. Some guidelines recommend it routinely when evaluating nodules.¹
Molecular diagnostics: genetic testing of the aspirated material (e.g. for BRAF, RAS mutations) can sharpen the diagnosis when cytology is unclear.
Surgery is the primary treatment for thyroid cancer.¹
StandardSurgical procedures
Total thyroidectomy
Complete removal of the thyroid gland. Usually the standard procedure for differentiated thyroid cancer, especially for tumours above a certain size or with risk factors.
Hemithyroidectomy
Removal of one thyroid lobe. Can be sufficient for small, low-risk papillary carcinomas in certain situations. The guideline defines criteria for when a hemithyroidectomy is acceptable.¹
Lymph node dissection
Affected neck lymph nodes are removed as well. A central lymph node dissection is recommended in certain constellations.
Possible complications — choose an experienced centre
Risks of thyroid surgery: recurrent laryngeal nerve palsy (damage to the nerve of the vocal cords, hoarseness) and hypoparathyroidism (damage to the parathyroid glands, calcium deficiency). The risks depend strongly on the surgeon's experience — an experienced thyroid centre is recommended.
7. Treatment: radioiodine therapy
Radioiodine therapy (RAI) is used after surgery for differentiated thyroid carcinomas.¹
Principle
Radioactive iodine (I-131) is taken and accumulates selectively in remaining thyroid tissue and in iodine-storing metastases. The radiation destroys this tissue in a targeted way.
Indication
Usually recommended for differentiated carcinomas after total thyroidectomy — to ablate remaining thyroid tissue and to destroy any tumour cells that may remain. The indication depends on the risk profile (tumour size, lymph node involvement, distant metastases).
Not for everyone
For very small, low-risk papillary carcinomas, radioiodine therapy can be omitted under certain conditions.¹
Medullary and anaplastic carcinoma
These forms do not respond to radioiodine, as they do not store iodine. Other treatment approaches are used here (e.g. targeted therapies such as BRAF/MEK inhibitors for anaplastic carcinoma).
8. Follow-up and levothyroxine
Levothyroxine replacement
After total thyroidectomy, lifelong replacement with levothyroxine (L-thyroxine) is necessary. With a differentiated carcinoma, levothyroxine is usually dosed so that the TSH value is suppressed (TSH suppression) — because TSH can stimulate the growth of any remaining tumour cells. The degree of suppression depends on the risk profile.¹
Thyroglobulin (Tg)
The most important tumour marker for differentiated thyroid carcinomas in follow-up. It is checked regularly after total thyroidectomy and radioiodine therapy. A rise can indicate a recurrence.
Ultrasound
Regular ultrasound checks of the neck (thyroid bed, neck lymph nodes) are part of standard follow-up.
Follow-up intervals
Initially close-meshed (every three to six months), later at longer intervals if the finding is stable. Follow-up is lifelong.
Taking the medication
Levothyroxine in the morning on an empty stomach, with a time gap from iron preparations, calcium and PPIs. More: Medications before or after eating.
9. Prognosis
The prognosis of thyroid cancer depends strongly on the form.¹
Papillary carcinoma — very good prognosis; the vast majority of those affected are cured
Follicular carcinoma — good prognosis; somewhat worse than papillary, but usually well treatable
Medullary carcinoma — the prognosis depends on the stage; usually good with early diagnosis
Anaplastic carcinoma — unfavourable prognosis; new targeted therapies can help in certain cases
Overall, thyroid cancer is among the cancers with the best prognosis of all. After successful treatment, many of those affected lead a normal life — with the proviso that levothyroxine must be taken for life and follow-up must be attended consistently.
How brite helps you with thyroid cancer
Levothyroxine on an empty stomach every morning, regular TSH and thyroglobulin checks, lifelong follow-up across endocrinology, nuclear medicine and oncology — care after thyroid cancer runs over decades. brite helps you keep the overview.
Medication reminder — levothyroxine strictly on an empty stomach (at least thirty minutes before breakfast), calcium or iron with a gap: brite reminds you on time. With TSH suppression, correct daily intake is especially important. Set up a reminder
Interaction check — levothyroxine doesn't get along with everything: iron, calcium, magnesium, PPIs (pantoprazole/omeprazole), soy products and some antacids reduce its absorption. brite shows the critical combinations and the necessary time gaps between doses. Check now
Health history — document TSH, thyroglobulin (the most important tumour marker), calcium and follow-up appointments over time. At your next appointment in endocrinology or nuclear medicine, show the real course — Tg stable or rising? Track your history
Digital medication plan — all your medications clearly laid out for endocrinology, nuclear medicine, oncology and your family doctor. Especially important before examinations with iodine-containing contrast medium or before radioiodine therapy (iodine restriction). Go to medication plan
The most common forms (papillary, follicular) are usually highly curable with early diagnosis and guideline-based treatment. The prognosis is among the best of all cancers.¹
Not always. For small, low-risk papillary carcinomas, a hemithyroidectomy (removal of one lobe) can be sufficient under certain conditions. For larger tumours or risk factors, total thyroidectomy is usually recommended.¹
After surgery, radioactive iodine (I-131) is taken, which accumulates in remaining thyroid tissue and iodine-storing metastases and destroys it in a targeted way. It is used for differentiated carcinomas. The therapy usually requires a short inpatient stay.¹
Yes — after total thyroidectomy, levothyroxine must be taken for life, because without a thyroid the body can no longer produce thyroid hormones. The dose is adjusted so that the TSH value is suppressed or kept within the normal range, depending on the risk profile.
A protein produced only by thyroid tissue. After complete removal of the thyroid and radioiodine therapy, thyroglobulin should no longer be detectable in the blood. A rise during follow-up can indicate remaining thyroid tissue or a recurrence.¹
A rarer form of thyroid cancer that arises from the calcitonin-producing C cells. It can occur sporadically or hereditarily (MEN 2 syndrome, RET mutation). Calcitonin in the blood is the most important tumour marker. It does not respond to radioiodine.
Initially every three to six months (blood draw: TSH, thyroglobulin; neck ultrasound). If the finding is stable, the intervals can be lengthened. Follow-up is lifelong — even with cured thyroid cancer.
A recurrence is possible, but relatively rare with differentiated carcinomas. Regular follow-up (thyroglobulin, ultrasound) serves early detection. Recurrences can usually be treated well.
Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or treatment. The treatment of thyroid cancer should usually be carried out in a specialized centre. Levothyroxine after thyroid surgery must be taken for life and should not be dosed or stopped on your own. Last updated: April 2026.
