Differentiated thyroid cancer Flashcards
What are the histological classifications of thyroid cancer?
Papillary
Follicular
Medullary
Anaplastic
What do most differentiated thyroid cancers take up, secrete and are driven by?
Take up iodine
Secrete thyroglobulin
Driven by TSH
How do differentiated thyroid cancers present?
Palpable nodule
5% present with a local or disseminated met
Where will papillary thyroid cancer spread?
Via lymph to lungs, bone, liver and brain
What autoimmune disease is papillary thyroid cancer associated with?
Hashimotos
Where is the incidence of follicular carcinoma higher?
Regions of relative iodine deficiency
How are thyroid carcinomas investigated?
Ultrasound guided FNA
Excision biopsy of lymph node
If vocal cord palsy, do pre-op laryngoscopy
What are the clinical predictors of malignancy?
New thyroid nodule age Male Nodule increasing in size Lesion over 4 cm in diameter History of head and neck irradiation Vocal cord palsy
How are thyroid cancers treated?
Surgery treatment of choice - thyroid lobectomy with isthmusectomy
Sub-total thyroidectomy
Total thyroidectomy
What risk stratification is used post op?
AMES Age Mets Extent of tumour Size of tumour
Who is AMES low risk?
Younger patients (women <50, men <40) with no evidence of mets Older patients with intathyroid papillary lesion with no distant mets
What are the 20 year survival for AMES low risk?
99%
Who are AMES high risk?
Distant mets
Extra Thyroid disease in those with papillary cancer
Significant capsular invasion with follicular cancer
Primary tumour over 5cm
What is the 20 year survival in AMES high risk?
61%
When is a thyroid lobectomy with isthmusectomy used?
Papillary microcarcinoma (<1cm)
Minimally invasive follicular with capsular invasion only
AMES low risk
When is a sub-total or total thyroidectomy used?
DTC with extra-thyroid spread Bilateral or multifocal DTC Distant mets Nodal involvement AMES high risk
What is the post op care after thyroid surgery?
Calcium check within 24 hours
Calcium replacement if calcium falls below 2 mmol/l
IV calcium for levels below 1.8 mmol/l or if symptomatic
Discharged on T3 or T4
When is whole body iodine scanning used?
Undergone sub-total or total thyriodectomy
3-6mnths post op
What is the pharma regime before a whole body iodine scan?
T4 stopped 4 weeks prior
T3 stopped 2 weeks prior
TSH greater than 20
What is thyroid remnant ablation?
Radiation aimed at thyroid
Ablate residual thyroid tissue in order to destroy occult microfoci
What can be used as a tumour marker?
Thyroglobulin
