Thyroid Cancer

Question 1

what is the definition of thyroid cancer?

Answer 1

cancer of the cells in the thyroid

Question 2

what is the epidemiology of thyroid cancer?

Answer 2

• Not common, but are responsible for 400 deaths annually in the UK
• More common in FEMALES than males

Question 3

what is the aetiology of thyroid cancer?

Answer 3

radiation

Question 4

what are the risk factors for thyroid cancer?

Answer 4

exposure to radiation, genetic predisposition

Question 5

what is the brief pathophysiology of thyroid cancer?

Answer 5

• Minimally active hormonally
• Over 90% secrete thyroglobulin which can be used as a tumour marker after thyroid ablation
• Carcinomas derived from thyroid epithelium may be:
• Differentiated - papillary or follicular
• Undifferentiated - anaplastic

Question 6

what are the differenet type of thyroid cancer?

Answer 6

• Papillary (70%): Most common, well differentiated, Young people, local spread and good prognosis, Arise from thyroid epithelium
• Follicular (20%): Middle age, spread to lung/bone, usually good prognosis, Well differentiated, arise from thyroid epithelium
• Anaplastic (<5%): Very undifferentiated and arise from thyroid epithelium, Aggressive, local spread but poor prognosis
• Lymphoma (2%)
• Medullary cell (5%) - arise from calcitonin C cells of thyroid gland

Question 7

what are the key presentations of thyroid cancer?

Answer 7

• In 90% they present as thyroid nodules
• Occasionally (5%) they present with cervical lymphadenopathy or with lung, cerebral, hepatic or bone metastases
• If thyroid gland increases in size, becomes hard and is irregular in shape - think carcinoma
• Patients may complain of dysphagia or hoarseness of voice due to tumour compression on surrounding structures i.e. oesophageal and laryngeal nerve

Question 8

what are the signs of thyroid cancer?

Answer 8

Thyroid nodules, cervical lymphadenopathy or with lung, cerebral, hepatic or bone metastases, increased size of thyroid, hard thyroid, irregularly shaped thyroid

Question 9

what are the symptoms of thyroid cancer?

Answer 9

dysphagia or hoarseness of voice

Question 10

what are the first line investigations for thyroid cancer?

Answer 10

• Fine needle aspiration cytology biopsy: to distinguish between benign or malignant nodules

Question 11

what are the gold standard investigations for thyroid cancer?

Answer 11

• Blood test - to check TFTs (TSH, T4 & T3): To check if hyperthyroid or hypothyroid - needs to be treated before carcinoma surgery
• Ultrasound of thyroid: Can differentiate between benign or malignant

Question 12

what are the differential diagnoses for thyroid cancer?

Answer 12

goitre

Question 13

how is thyroid cancer managed?

Answer 13

• Thyroid LOVES iodine so will readily take up radioactive iodine which in turn will locally irradiate and destroy cancer - providing very little radiation damage to other surrounding structures
• Administer lots of LEVOTHYROXINE (T4) to keep TSH reduced as this is a growth factor for cancer
• Chemotherapy helps to reduce risk of spread and treats micro-metastases that have been undetected
• Papillary and follicular carcinomas:
  • Total thyroidectomy
  • Ablative radioactive iodine
• Anaplastic carcinomas and lymphomas:
  • DO NOT respond to radioactive iodine
  • External radiotherapy provides brief respite - mainly palliative
• Medullary carcinoma:
  • Thyroidectomy and lymph node removal

Question 14

how is thyroid cancer monitored?

Answer 14

Repeat blood tests, ultrasounds and radioactive scanning of the neck

Question 15

what are the complications of thyroid cancer?

Answer 15

Injury to the voice box and hoarseness after thyroid surgery.
Low calcium level from accidental removal of the parathyroid glands during surgery.
Spread of the cancer to the lungs, bones, or other parts of the body.

Question 16

what is the prognosis of thyroid cancer?

Answer 16

Most patients cured after 5 years, around 90% survival first year, falls slightly after 5 years, 84% expected to survive after 10 years