Quick answer
What is thyroid cancer?
Thyroid cancer is cancer of the thyroid gland in the neck — often found as painless lump or incidentally on scan. Papillary thyroid cancer is commonest and has excellent prognosis — over 90% 10-year survival. Most need surgery (partial or total thyroidectomy) and may receive radioactive iodine. Thyroid function blood tests are usually normal. See a GP for lump in front of neck moving on swallowing, hoarse voice, or neck lymph nodes — 2-week wait referral. Very treatable compared with many cancers when caught early.
Thyroid cancer — usually highly treatable
Thyroid cancer arises from thyroid follicular or parafollicular cells — ~3,900 UK cases/year — rising incidental detection.
Papillary carcinoma — 80% — excellent prognosis
Presentation
Classic:
- Painless anterior neck nodule
- Moves with swallow
- Normal TFTs usually
Concerning features (U3–U5 ultrasound):
- Solid hypoechoic nodule
- Irregular margins
- Microcalcifications
- Taller than wide
- Extrathyroidal extension
- Abnormal lymph nodes
See underactive thyroid — goitre common — most nodules benign
Diagnosis pathway
- Examination + TFTs
- Ultrasound + U classification
- FNA if U3–U5 or suspicious nodes
- Bethesda cytology — I–VI
- Surgery if malignant/indeterminate high risk
Histological types
| Type | Origin | Behaviour |
|---|---|---|
| Papillary | Follicular cells | Indolent, lymph node spread common |
| Follicular | Follicular cells | Haematogenous spread |
| Medullary | C cells | Calcitonin, RET proto-oncogene |
| Anaplastic | Dedifferentiated | Aggressive |
Treatment
Surgery:
- Hemithyroidectomy — low-risk micro papillary
- Total thyroidectomy — larger, multifocal, nodes, high risk
Radioactive iodine (I-131):
- Ablation remnant and micrometastases
- Only works differentiated — papillary/follicular
- Low-iodine diet preparation
Levothyroxine:
- Replacement lifelong
- TSH suppression — high-risk years — balance vs osteoporosis/AF risk
Follow-up
Thyroglobulin — tumour marker post-total thyroidectomy
Neck ultrasound — annual early years
Most return to normal life — pregnancy safe after stable remission — levothyroxine adjusted
Neck lump at Adam’s apple level moving on swallow — GP ultrasound — likely benign, cancer if present usually curable.
Common questions
- What are the symptoms of thyroid cancer?
- Painless neck lump in thyroid area moving on swallowing — often only sign. Hoarse voice if recurrent laryngeal nerve involved. Difficulty swallowing, neck lymph node enlargement, rarely stridor. Usually normal thyroid function blood tests — not hyper or hypothyroid from cancer itself. Many found incidentally on carotid or chest CT.
- What are the types of thyroid cancer?
- Papillary — commonest, best prognosis. Follicular — may spread via blood to bone/lung. Medullary — from C cells, calcitonin marker, sometimes genetic (MEN2). Anaplastic — rare, aggressive, older patients. Lymphoma of thyroid — rare, distinct treatment.
- How is thyroid cancer diagnosed?
- Ultrasound thyroid with U classification of nodules. Fine needle aspiration biopsy — cytology Bethesda category. Staging CT/MRI if advanced disease. Serum calcitonin if medullary suspected. Post-surgery histology confirms type and risk stratification.
- How is thyroid cancer treated?
- Surgery — hemithyroidectomy for low-risk unifocal microcarcinoma or total thyroidectomy for larger/multifocal/high-risk. Radioactive iodine ablation (I-131) for selected intermediate/high-risk differentiated thyroid cancer. Lifelong levothyroxine after total thyroidectomy. External radiotherapy for anaplastic or unresectable disease.
- What is the outlook for thyroid cancer?
- Papillary — 10-year survival over 90% — one of the most curable cancers. Recurrence monitored with thyroglobulin blood test and neck ultrasound. Most live normal lifespan. Anaplastic — poor prognosis — rare.