Differentiated thyroid cancer

Question 1

What are they types of differentiated thyroid cancer (DTC)?

Answer 1

Papillary and follicular

Question 2

Which substance drives DTC?

Answer 2

Thyroid stimulating hormone

Question 3

What do DTCs take up and secrete?

Answer 3

Take up: Iodine and secrete: thyroglobulin

Question 4

What are the demographics of DTC?

Answer 4

Commoner in females (risk increases until middle age then plateaus) than males (risk increases with age), uncommon in children, lower incidence in black people

Question 5

What is the epidemiology of DTC?

Answer 5

Strong associations with radiation, weak associations with adenoma, chronic elevation of TSH and increasing number of children

Question 6

How does DTC present?

Answer 6

Palpable nodes

Less commonly local of disseminated metastases

Question 7

What is the commonest type of thyroid cancer?

Answer 7

Papillary (followed by follicular)

Question 8

How does papillary thyroid cancer tend to spread and to where?

Answer 8

Lymphatics to cervical nodes

Question 9

How does follicular thyroid cancer tend to spread and to where?

Answer 9

Haematogenously to brain, bones, liver and brain

Question 10

What pathology is papillary cancer associated with?

Answer 10

Hashimoto’s thyroiditis

Question 11

What deficiency is follicular cancer associated with?

Answer 11

Iodine

Question 12

What is the prognosis of DTC?

Answer 12

Very, very good

Question 13

How are suspected DTCs investigated?

Answer 13

Ultrasound guided FNA +/- excision biopsy of lymph nodes

Question 14

How are suspected DTCs investigated if there is vocal cord palsy?

Answer 14

Pre-operative laryngoscopy

Question 15

What are the clinical predictors of DTC cancer?

Answer 15

Nodule aged 50
Male
Increasing size
>4cm diameter
History of irradiation
Vocal cord palsy

Question 16

How is DTC treated?

Answer 16

Surgically - lobectomy + isthmusectomy OR sub-total thyroidectomy OR total thyroidectomy

Question 17

What is the risk scoring system for DTC?

Answer 17

A - age
M - metastases
E - extent of tumour
S - size of tumour

Question 18

When is a lobectomy with isthmusectomy used?

Answer 18

Microcarcinomas (

Question 19

When are sub total or total thyroidectomys used?

Answer 19

Extra-thryoidal spread
Bilateral/multifocal involvement
Distant metastases
Nodal involvement
High risk AMES

Question 20

How is lymph node surgery used in DTC?

Answer 20

Papillary - central compartment clearance with biopsy of lateral nodes
Follicular - central compartment clearance

Question 21

What must be checked following thyroid surgery?

Answer 21

Calcium

Question 22

How is a calcium deficiency treated post-thyroid surgery?

Answer 22

Replacement if calcium below 2 mmol/l

IV replacement if calcium below 1.8 mmol/l

Question 23

What medication must a patient be given following thyroid surgery?

Answer 23

T3 or T4 (commonly T4)

Question 24

When and why is whole body iodine scanning used?

Answer 24

3-6 months after subtotal or total thyroid surgery to check that all the thyroid tissue has been cleared

Question 25

What must be stopped prior to whole body iodine scanning?

Answer 25

T3 - 2 weeks prior | T4 - 4 weeks prior

Question 26

When might a patient undergo thyroid remnant ablation?

Answer 26

If uptake of iodine on a full body iodine scan is more than >0.1% of the ingested dose

Question 27

How is thyroid remnant ablation carried out?

Answer 27

Administration of I-131 with extensive radiation precautions

Question 28

What are the side effects of thyroid remnant ablation?

Answer 28

Sialadenitis (salivary gland inflammation) and/or sore throat

Question 29

What level should TSH and free T4 ideally be below following treatment for DTC?

Answer 29

TSH below 0.1mU/l | Free T4 below 25

Question 30

Which substance can be used as a tumour marker (i.e a marker of recurrence)?

Answer 30

Thyroglobulin

Question 31

What are the long term affects of thyroid remnant ablation?

Answer 31

Small increase in acute myeloid leukemia

Question 32

How can recurrent disease be detected?

Answer 32

Rising thyroglobulin | Imaging (whole body thyroid uptake scan, PET)