Differentiated thyroid cancer Flashcards
What are they types of differentiated thyroid cancer (DTC)?
Papillary and follicular
Which substance drives DTC?
Thyroid stimulating hormone
What do DTCs take up and secrete?
Take up: Iodine and secrete: thyroglobulin
What are the demographics of DTC?
Commoner in females (risk increases until middle age then plateaus) than males (risk increases with age), uncommon in children, lower incidence in black people
What is the epidemiology of DTC?
Strong associations with radiation, weak associations with adenoma, chronic elevation of TSH and increasing number of children
How does DTC present?
Palpable nodes
Less commonly local of disseminated metastases
What is the commonest type of thyroid cancer?
Papillary (followed by follicular)
How does papillary thyroid cancer tend to spread and to where?
Lymphatics to cervical nodes
How does follicular thyroid cancer tend to spread and to where?
Haematogenously to brain, bones, liver and brain
What pathology is papillary cancer associated with?
Hashimoto’s thyroiditis
What deficiency is follicular cancer associated with?
Iodine
What is the prognosis of DTC?
Very, very good
How are suspected DTCs investigated?
Ultrasound guided FNA +/- excision biopsy of lymph nodes
How are suspected DTCs investigated if there is vocal cord palsy?
Pre-operative laryngoscopy
What are the clinical predictors of DTC cancer?
Nodule aged 50 Male Increasing size >4cm diameter History of irradiation Vocal cord palsy
How is DTC treated?
Surgically - lobectomy + isthmusectomy OR sub-total thyroidectomy OR total thyroidectomy
What is the risk scoring system for DTC?
A - age
M - metastases
E - extent of tumour
S - size of tumour
When is a lobectomy with isthmusectomy used?
Microcarcinomas (
When are sub total or total thyroidectomys used?
Extra-thryoidal spread Bilateral/multifocal involvement Distant metastases Nodal involvement High risk AMES
How is lymph node surgery used in DTC?
Papillary - central compartment clearance with biopsy of lateral nodes
Follicular - central compartment clearance
What must be checked following thyroid surgery?
Calcium
How is a calcium deficiency treated post-thyroid surgery?
Replacement if calcium below 2 mmol/l
IV replacement if calcium below 1.8 mmol/l
What medication must a patient be given following thyroid surgery?
T3 or T4 (commonly T4)
When and why is whole body iodine scanning used?
3-6 months after subtotal or total thyroid surgery to check that all the thyroid tissue has been cleared
What must be stopped prior to whole body iodine scanning?
T3 - 2 weeks prior
T4 - 4 weeks prior
When might a patient undergo thyroid remnant ablation?
If uptake of iodine on a full body iodine scan is more than >0.1% of the ingested dose
How is thyroid remnant ablation carried out?
Administration of I-131 with extensive radiation precautions
What are the side effects of thyroid remnant ablation?
Sialadenitis (salivary gland inflammation) and/or sore throat
What level should TSH and free T4 ideally be below following treatment for DTC?
TSH below 0.1mU/l
Free T4 below 25
Which substance can be used as a tumour marker (i.e a marker of recurrence)?
Thyroglobulin
What are the long term affects of thyroid remnant ablation?
Small increase in acute myeloid leukemia
How can recurrent disease be detected?
Rising thyroglobulin
Imaging (whole body thyroid uptake scan, PET)
