Thyroid Tumours Flashcards
The incidence of papillary and follicular tumours are falling?
False
Incidence is increasing as the mortality falls
What in papillary and follicular tumours is there a strong association with?
Radiation exposure
Are follicular and papillary tumours TSH Independent?
False they are TSH dependant
Most take up iodine and secrete thyroglobulin
What ways are follicular and papillary tumours found?
Palpable lump
Small chance findings from thyroidectomy
5% present the pathological Metastatic disease
What are follicular tumours strongly linked to?
Iodine deficiency
How do papillary tumours prefer to spread?
Lymph
How do follicular tumours prefer to spread?
Haematogenous
What is the main investigation for thyroid tumours?
Ultrasound with fine needle aspiration
+/- excision biopsy of lymph nodes
What isn’t used in the investigation of thyroid tumours?
No CT, MRI or thyroid scan
What are some clinical predictors of malignancy?
Thyroid nodule is <20 or over >50
Head and neck irradiation
Rapidly growing
What is the mainstay of treatment in thyroid tumours?
Thyroidectomy and RAI
What is RAI
Radioactive Iodine therapy
What is the scale used for determining severity of disease?
AMES
What factors determine the AMES score?
Age
Metastasis
Extent of primary tumour
Size of primary tumour
What would be a stereotypical low AMES score?
Young with no metastatic disease
Old with a minimally invasive primary
What would be a stereotypical high AMES score?
Distant metastasis
Extra-thyroid disease
Capsular invasion (follicular)
What is the surgery usually used in a low AMES risk?
Thyroid lobectomy with isthmus
What would indicate a lobectomy?
Papillary Microcarcinoma <1cm
Minimally invasive follicular
What is the surgery usually used in a high risk AMES score?
Sub or total thyroidectomy
What would indicate a sub or total thyroidectomy?
Differentiated thyroid cancer + extra thyroidal spread
- distant mets or nodal involvement
Bilateral or multifocal tumours
In papillary cancer what is the nodal clearance?
Central compartment clearance
Lateral node sampling
In follicular cancer what is the nodal clearance?
Central compartment clearance
What is done acutely in post operative care?
Calcium is checked 24 hours post surgery
At what level is the calcium meant to be above?
2 mmol/l
What level of calcium requires urgent treatment?
1.8 mmol/l
IV calcium
What is done 3-6 months post operatively ?
Whole body iodine scan
In what circumstances is a whole body iodine scan completed?
High AMES risk
Sub or total thyroidectomy
What is key in a whole body iodine scan?
Must have high TSH level to drive iodine uptake
How are high TSH levels ensured in whole body iodine scan?
T3/4 injection are stopped weeks before
rhTSH is injected
If the scan as taking place in a week what is the timeline?
rhTSh administered on the Monday and Tuesday
Iodine capsule is given on the Wednesday
What iodine isotope is used?
I-131
Why do the tumours take up the iodine?
Synthetically induced high TSH levels and the fact the tumours are TSH dependant
What does the scan show?
Any thyroid remnants
Any tumour which takes up the iodine
In Thyroid remnant ablation therapy how many capsules are given?
2 or 3
200x more radiation than diagnostic
How are patients prepared for ablation therapy?
Same as in whole body iodine scan
What precautions are taken in ablation therapy?
Lead lined room
Sewage connected directly to the mains
Disposable cutlery clothes and bedding
Minimal/ no nurse and family contact
What level can patients be discharged?
radiation must be below 500 cps at 1 metre
How long does the level take to drop to a safe level?
usually 48 hours
What are the side effects of ablation therapy?
Sore throat
What is key in the follow up post ablation therapy?
Maintained in T4
Suppress TSH to prevent growth
What can be used a tumour marker post ablation?
Thyroglobulin levels
What should TSH levels be kept below?
<0.1 mU/l
Why should TSH levels be suppressed?
TSH drives the growth of the tumour, by reducing levels you can inhibit the growth of the tumour
List long term effects of ablation therapy
Small increased risk of acute myeloid leukemia
Does ablation therapy increase your risk of tumour developmen?
No
In what time period is recurrence most likely to occur?
Within the first two years
Which tumour caries the greatest risk of recurrence in the same sight?
Pappiliary
If a follicular tumour where to recur where would it be most likely to?
Lung
Bone
Brain
If there is a rising thyroglobulin level but the whole body iodine scan is negative what might have occurred and what is the correct corse of action?
Tumour has become anaplastic
PET scan the entire body
