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The Endocrine System > Differentiated Thyroid Cancer > Flashcards

Flashcards in Differentiated Thyroid Cancer Deck (32)
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1

Why can differentiated thyroid cancers be hard to detect?

  1. Histologically similar to normal
  2. Physiologically similar to normal

2

How do differentiated thyroid cancers differ from normal tissue?

  1. They secrete thyroglobulin
  2. They take up iodine to a greater extent

3

Which population of people have a particularly low incidence of differentiated thyroid cancer?

Afro-americans

4

Lifestyle factors such as smoking and obesity increase risk of differentiated thyroid cancer

True or false?

False

An individual cannot really predispose themselves to this type of cancer

5

What can cause a rise in DTC cases?

Nuclear incidents

(this will happen around 25 years after the incident)

6

How do DTCs often present?

  1. Palpable nodule in the neck - either part of the thyroid of a lymph node
  2. Pathological fractures

7

Cervical lymphadenopathy is associated most with which DTC?

Papillary thyroid carcinoma

(spreads lymphatically)

8

Distant metastasis is most associated with which DTC and why?

Follicular thyroid carcinoma

(spreads haematogenously)

9

Which investigations may be used for DTC?

  1. USS-FNA
  2. Excision of lymph nodes
  3. Pre-operative laryngography (if there is vocal cord palsy)

10

What are the three surgical options for DTC treatment?

  1. Thyroid lobectomy
  2. Sub-total thyroidectomy
  3. Total thyroidectomy

11

What is one postive aspect and one negative aspect to thyroid lobectomy?

Positive - Less invasive and lower mortality

Negative - Remaining thyroid poses cancer recurrence risk

12

What does a subtotal thyroidectomy involve?

Leaving 5-10% of the thyroid gland present during removal

13

What is the main issue with total thyroidectomy?

Risks post-operative complications

(e.g. recurrent laryngeal nerve palsy)

14

For high risk patients, which other treatment option may be used in DTC?

Radioiodine

15

Why may hypocalcaemia develop post-operatively for a DTC?

Damage or accidental removal of parathyroid glands

16

In patients who have undergone subtotal or total thyroidectomy, what will be done 3-6 months post op?

Whole body iodine scan

17

In order for a whole body iodine scan to show up remaining tumour, or metastasis, which hormone must be high?

TSH

(these tumours are TSH driven)

18

How can TSH levels be boosted prior to a whole body iodine scan?

Recombinant human TSH (rhTSH) can be given as an injection

19

Why is the use of rhTSH in the patient's interest?

It can be used in conjunction with T3/4

No symptoms of hypothyroidism need be experienced as T3/4 do not need to be stopped this way

20

If differentiated thyroid cancer is found on a whole body iodine scan, what is the next stage in treatment?

250x dose (compared to scanning) of RAI is given to destroy cells

The patient is hospitalised in alead lined room

21

What are the main systemic side effects of RAI?

No major side effects

Salivary glands and throat may be sore

22

What does the follow up to RAI therapy involve?

Supressing TSH <0.1mU/L to minimise recurrence

Thyroxine can aid with this (must be < 25 however)

23

What can be used as a tumour marker in DTC?

Thyroglobulin levels

24

What should the thyroglobulin levels be after RAI treatment?

They should be undetectable

25

In which patients is thyroglobulin not a useful tumour marker?

Patients with a thyroid lobectomy

Haf the thyroid gland remains to produce physiological thyroglobulin which masks any produced by a tumour

26

What is the main risk associated with RAI treatment?

Incidence of acute myeloid leukaemia is increased 50%

(1 : 25,000 down to 1 : 13,000)

27

What is the expected prognosis for DTC?

Best of all cancer excluding non-melanoma skin cancer

28

Recurrent DTC will likely present within what length of time post-treatment?

2 years

29

Why is recurrent DTC not "the end of the world"?

It is still very curable

(I-131 scan and RAI treament again)

30

Why is a rising thyroglobulin but negative I-131 whole body scan worrying?

Suggests de-differentiated thyroid cancer

This behaves like an anaplastic cancer