Thyroid Cancer
NICE guideline [NG230] Thyroid cancer: assessment and management. Published: Dec 2022.
NICE guideline [NG145] Thyroid disease: assessment and management. Last updated: Oct 2023.
Overview of Thyroid Cancer
Shared Clinical Features
- Painless lump in the neck – often the first and only symptom
- Slow progressive enlargement
- Lump moves on swallowing but NOT on tongue protrusion
- Mass effect (if the lump is large)
- On oesophagus → dysphagia
- On trachea → dyspnoea
- Non-specific neck fullness / discomfort
- Dysphonia (if the tumour invades / compresses the recurrent laryngeal nerve)
Importantly, most thyroid cancers do NOT cause hyper- or hypothyroid symptoms; TFTs are often normal. This key feature differentiates thyroid cancer from other causes of thyroid mass (e.g. Graves’ disease, toxic adenoma, toxic multinodular goitre)
Type-Specific Features
[Ref]
| Type | Histology | Characteristics | Distribution |
|---|---|---|---|
| Papillary thyroid carcinoma | Tissue of origin: thyrocytes
Well differentiated – ground-glass nuclei with psammoma bodies |
|
Most common type of thyroid cancer (~80% cases) |
| Follicular thyroid carcinoma | Tissue of origin: thyrocytes
Well differentiated – many colloid-filled follicles, resembling normal thyroid tissue |
|
|
| Medullary thyroid carcinoma | Tissue of origin: C cells (parafollicular cells)
Poorly differentiated –polygonal / spindle-shaped cells associated with amyloid deposits |
~30% associated with MEN2 syndrome, the rest is sporadic
Secretes calcitonin, which can cause a carcinoid syndrome-like presentation:
|
|
| Anaplastic thyroid carcinoma | Tissue of origin: thyrocytes
Poorly differentiated – pleomorphic giant cells |
|
|
| Thyroid lymphoma | Most common: large atypical B cells (diffuse large B-cell lymphoma)
2nd most common: lymphoepithelial lesions (MALT lymphoma) |
|
|
Investigation and Diagnosis
1st line: ultrasound neck – malignancy-suggesting features
- If ultrasound is abnormal → perform ultrasound-guided final needle aspiration for cytology
- Further testing (if needed) → core needle biopsy
Tumour markers (NICE does not recommend routine measuring for diagnosis, but it’s important to learn for exams):
- Medullary thyroid carcinoma: calcitonin
- Other types of cancer (papillary, follicular, etc): thyroglobulin
Management
Definitive Management
Key management principles:
- Surgical management (total thyroidectomy or hemithyroidectomy) is the standard of care for most patients with thyroid cancer
- Radioactive iodine is primarily used as an adjunctive treatment following surgical intervention in, rather than as an isolated therapy (unlike in Graves disease where radioactive iodine is a well-established primary treatment)
- Active surveillance is only reserved for those with solitary microcarcinoma
There are 3 main scenarios:
| Recommended management | Indications |
|---|---|
Surgery is optional:
|
|
Surgery needed:
|
|
| Total thyroidectomy |
|
| Compartment-oriented central / lateral neck dissection |
|
Post-Operative Supplementation
Levothyroxine (life-long) is standardly offered after total thyroidectomy for thyroid cancer to maintain euthyroid status
- If the patient underwent hemithyroidectomy, levothyroxine is only offered if the patient develops hypothyroidism
Calcium and vitamin D supplementation is recommended post-thyroidectomy to prevent transient hypocalcaemia due to parathyroid manipulation / injury
- Long-term supplementation is only offered if there are persistent hypoparathyroidism
Adjunct Management
As a blunt rule, the following is generally offered to those needing a total thyroidectomy (refer to 3rd row in the table above):
| Thyrotropin alfa (recombinant human TSH) | To be given before radioactive iodine to maximise radioactive iodine uptake |
| Radioactive iodine | To be given after thyroidectomy to ablate residual thyroid tissue |
| TSH suppression with levothyroxine | To be given to reduce risk of recurrence (to limit TSH-driven stimulation of residual or metastatic differentiated thyroid cancer cells)
|
Consider external beam radiotherapy if there is macroscopic disease after surgery or local disease that is unlikely to be controlled with radioactive iodine
Post-Thyroidectomy Monitoring
NICE recommends measuring:
- Thyroglobulin (detectable thyroglobulin levels suggest residual thyroid tissue or residual or recurrent cancer), and
- Thyroglobulin antibodies (the presence of thyroglobulin antibodies would affect the measurement of thyroglobulin levels)
- Neck ultrasound
Other commonly measured parameters in practice:
- TFTs are also routinely monitored in practice to detect the development of hypothyroidism and to titrate levothyroxine dose (for those who are on it)
- Calcium level to detect hypoparathyroidism.