Papillary Carcinoma of the Thyroid

Question 1

what % of thyroid carcinomas are papillary?

Answer 1

75-85%

Question 2

what is it?

Answer 2

most common form of thyroid cancer
usually a solitary nodule in the thyroid - can be multifocal, often cystic and may be calcified - psammoma bodies
sometimes present with lymph node metastases - if find thyroid tissue or psammoma body in lymph node then search for occult papillary carcinoma
it is a differentiated thyroid cancer (DTC) - most take up iodine and secrete thyroglobulin and are driven by TSH

Question 3

where does it spread?

Answer 3

if haematogenous spread - lungs, bone, liver and brain

Question 4

who gets it?

Answer 4

associated with Hashimoto’s thyroiditis

Question 5

how does it present?

Answer 5

lesion in thyroid gland or cervical lymph node mass (metastasis)
local effects
- hoarseness
- dysphagia
- cough
- dysphonea
- all suggest locally advanced disease
haematogenous spread - uncommon and usually to the lung
overall good survival rates - worse with age >40 extra-thyroid extension and distant metastasis

Question 6

how is it investigated?

Answer 6

US and guided FNA of the lesion
can involve excision and biopsy of the lymph node
isotope biopsy, CT and MRI are not beneficial
pre-operative laryngoscopy if vocal cord palsy is clinically suspected

Question 7

how is it managed?

Answer 7

• Surgery is the choice treatment - Extent of surgery is variable
• Thyroid lobectomy with isthmectomy – papillary microcarcinoma <1cm
• Sub-total thyroidectomy – high risk
• Total thyroidectomy – high risk
• Follow up is determined by risk
• AMES – age, metastases, extent of primary tumour and size classifies risk at ninewells
• Low risk – no metastases and young m<40 and w<50, older patients with a minimally invasive follicular/intrathyroidal papillary lesion <5cm and no distant metastases – 99% 20 year survival
• High risk – distant metastases, extrathyroidal papillary cancer, significant capsular invasion with follicular carcinoma or primary tumour >5cm – 61% 20 year survival
• Lymph node – central compartment clearance and lateral lymph node sampling for papillary tumours
• TRA – Thyroid remnant ablation can be considered

Question 8

post operative management?

Answer 8

• Check calcium within 24 hrs
• Calcium replacement initiated if corrected falls below 2mmol/l
• IV calcium for calcium levels below 1.8mmol/l or symptomatic
• Discharge on T3 or T4
• Whole body iodine scan
o 3-6 months post-op
o T4 stopped 4 weeks before
o T3 stopped 2 weeks before
o rhTSH far better so don’t need to stop T3/T4
o TSH should be > 20 for best results
o Scan informs treatment decisions