Week 3 - F - Week 3 -Differentiated thyroid cancer

Question 1

What are the 4 types of thyroid cancer? (that we need to know) Which are differentiated and which are undifferentiated?

Answer 1

Papillary carcinoma - differentiated

Follicular carcinoma - differentiated

Medullary carcinoma - differentiated

Anaplastic carcinoma - undifferntiated

Question 2

Does a differentiated or undifferentiated thyroid cancer have a better prognosis?

Answer 2

Differentiated thyroid cancer has a better prognosis

Question 3

Exposure to what increases the risk of a thyroid cancer? What gender is thyroid cancers more common in?

Answer 3

Iodine radiation exposure

More common in females

Question 4

Does smoking have any association to thyroid cancer?

Answer 4

No known association

Question 5

What autoimmune condition is papillary thyroid cancer associated with? How does it tend to spread? Tends to have a good prgnosis

Answer 5

Associated with Hashimoto’s thyroditis

Spreads via lymphatics or haematogenous spread

95% survival at 10 years

Question 6

What is the second most common thyroid cancer? How does it spread and what people does it more commonly affect?

Answer 6

Follicular thyroid cancer

Spreads via haemategenous route

Slightly more common in areas with an iodine deficiency

Question 7

How is a biopsy of the thyroid usually taken? Are CT or MRI used?

Answer 7

Usually ultrasound-guided fine needle aspiration

No role for CT or MRI

Question 8

Due to the fact fine needle aspiration only examines cells and not the capsule, what type of thyroid carcinoma can FNA not be used in?

Answer 8

follicular carcinoma

– hence distinction between follicular adenoma and carcinoma cannot be made by FNA as it is invasion through the capsule that helps distinguish the follicular carcinoma from the follicular adenoma

Question 9

What is the substance that medullary thyroid cancers deposit in the tumour as amyloid?

Answer 9

Calcitonin

Question 10

Due to the high levels of calcitonin prduced by the medullary thyroid cancer, what may this do to calcium levels?

Answer 10

May cause hypocalcaemia

Question 11

What does parathyroid hormone do to calcium levels in the blood and how?

Answer 11

PTH increases the osteoclastic activity of bone causing calcium to be released into the blood therefore increasing calcaemia

Question 12

What age is an indicator of thyroid cancer?

Answer 12

Red flag age is similar to red flag for back pain

A new thyroid nodule at the age of less than 20 or greater than 50

Question 13

Other risk factors of thyroid cancer include: History of head and neck irradiation Vocal cord palsy

What size of nodule is a risk factor of thyroid cancer?

Answer 13

lesion > 4cm in diameter

Question 14

What is the treatment of choice in a thyroid cancer?

Answer 14

Surgery

Question 15

What is the classifaction system for low and high risk patients used by ninewells for people with tyroid cancer?

Answer 15

Age

Malignancy

Extent of primary tumour

Size of primary tumour

Question 16

If there is no capsular invasion in the patient, is this high risk or low risk?

Answer 16

This is a low risk patient

Question 17

In people with thyroid cancer All patients with distant metastases are high or low risk?

Answer 17

All patients with distant metastases are high risk

Question 18

Why are sub-total thyroidectomys carried out instead of total thyroidectomy?

Answer 18

Subtotal thyroidectomy is a surgical procedure, in which the surgeon leaves a small thyroid remnant in situ to preserve thyroid function, thereby preventing lifelong thyroid hormone supplementation therapy.

Question 19

When continuing post-operative care, what mineral level must be checked within 24 hours and why?

Answer 19

Check calcium levels as this can drop due to parathyroid glands also being removed

Question 20

How should calcium be administered if calcium levels fall below 1.8mmol/L? (normal range - 2.2 to 2.7 mmol/L)

Answer 20

Give intravenous calcium

Question 21

Why are whole body iodine scans carried out?

Answer 21

If the patient is suspected of metastases carry this out to see if there are any tumours elsewhere

Question 22

Why do TSH levels need to be high for a whole body iodine scan ? (preferably above 20)

Answer 22

Aim is to make cancer cells hungry for iodine this is done by increasing TSH levels which is increased by giving rhTSH (recombinant human TSH)

TSH causes T3 and T4 production by uptaking iodine and therefore any metastases will show clearly if TSH level is high

Question 23

Surgery is gold standard for thyroid cancer What is carried out following surgery?

Answer 23

Thyroid radiation ablation (with radioiodine) - Pre-treated with rhTSH as before

Question 24

What percentage of the thyroid radiation ablation (TRA) is excreted in the first 24 hours?

Answer 24

80%

Question 25

To ensure the uptake of iodine in the thyroid bed is now less than 0.1%, showing malignancy has been removed, what procedure is re-performed?

Answer 25

Re-perform the whole body iodine scan

Question 26

What is produced by thyroid cells and thyroid cancer cells that can be used as a tumour marker? – nothing else produces this, therefore after total thyroidectomy, if there level isn’t 0 as no thyroid cells exist, then there is cancer cells somewhere

Answer 26

Thyroglobulin

Question 27

If the patient has the gold standard, surgery, TRA and follow up, what disease can this increase the risk of by double?

Answer 27

Doubles risk of leukaemia

(Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal white blood cells that accumulate in the bone marrow and interfere with the production of normal blood cells.)

Question 28

What is the recurrence rate of thyroid cancer after the treatment?

Answer 28

30%

(Difficult group are those with rising Tg but negative whole body I-131 scan )