Thyroid cancer

Question 1

What are the red flags for malignancy?

Answer 1

• Rapid growth of nodule: CA (or can be haemorrhage into cyst)
• Hoarse voice (RLN involvement)
• Childhood history of H&N radiation/total body irradiation for bone marrow transplant
• Exposure to ionising radiation in childhood or adolescence
• FHx of thyroid CA
• MEN2 syndrome,
• background of Hashimoto (for lymphoma)

Question 2

What are the investigations for thyroid cancer?

Answer 2

Blood tests:

• TFT
• Thyroglobulin – tumour marker for differentiated thyroid tumours
• Carcinoembryonic antigen (CEA) – marker of thyroid medullary carcinomas
• Calcitonin
• Thyroid autoantibodies – Graves’ and Hashimoto’s disease (cytology in Hashimoto’s may be misinterpreted as features of malignancy)

U/S thyroid

• Determines type of swelling: diffuse, multinodular, solitary nodule
• Features of malignancy: solid, micro-calcification, ill-defined margin (infiltrative/ microlobulated), abnormal vascularity, palpable lymph nodes, “taller-than-wide” sign (spreads vertically > horizontally as this is how tumours grows), hypoechoic

Thyroid radioisotope scanning

• Measure uptake of radioactive iodine or technetium into metabolically active thyroid tissue
• Nearly all hot nodules are benign, 10-20% of cold nodules are malignant
• Useful in assessment of malignant thyroid metastases or ectopic thyroid tissue

FNAC

• Confirms malignancy
• Limitations: cannot differentiate follicular adenoma from a follicular carcinoma – requires demonstration of capsular invasion, sampling error when nodule >4cm

Question 3

What are the complications of thyroid cancer?

Answer 3

• Damage to recurrent laryngeal nerves (located in trachea-oesophageal grooves) OR invasion of larynx 🡪 hoarse voice, poor ‘breathy’ cough
• Invasion of oesophagus 🡪 dysphagia
• Trachea invasion or compression/displacement 🡪 shortness of breath
• Retrosternal extension 🡪 compression of mediastinal structures e.g. great veins 🡪 venous engorgement of the neck

Question 4

What are the indications for thyroid surgery?

Answer 4

4 ‘C’s indicative for surgery: Carcinoma, Compression (large goiter), Chemistry (e.g. hyperthyroidism that is uncontrolled), Cosmetic

Question 5

What is the cx of total thyroidectomy?

Answer 5

Bleeding/haematoma

Infection

Scar

RLN palsy (iarogenic) 🡪 is it unilateral or bilateral!

• Can be temporary because of the diathermy
• If really bad, can get aspiration + hoarseness

Hypocalcaemia

• Symptoms: perioral and fingertip paraesthesia
• Chvostek, Trousseau signs