9: Differentiated thyroid cancer

Question 1

Rank the types of thyroid cancer from most common to least common.

Answer 1

Papillary (absolutely most common)

Follicular

Medullary (C cells)

Anaplastic (killer)

Question 2

Papillary and follicular thyroid cancers are described as ___.

Answer 2

differentiated

Question 3

Differentiated thyroid cancers secrete ___ and take up ___.

Answer 3

secrete thyroglobulin (used as a tumour marker)

take up iodine (so iodine can be used to both investigate and kill the cancer)

Question 4

Which hormone drives papillary and follicular thyroid cancer?

Answer 4

TSH

Question 5

Differentiated thyroid cancers have a (good / bad) prognosis.

Answer 5

good prognosis

Question 6

Thyroid cancer is more common in (males / females).

Answer 6

females

Question 7

Thyroid cancer is strongly associated with exposure to what?

Answer 7

Radiation

Question 8

Thyroid cancer incidence increases following what type of accidents?

Answer 8

Nuclear incidents

e. g Chernobyl, Fukushima
www. theguardian.com/world/2014/mar/09/fukushima-children-debate-thyroid-cancer-japan-disaster-nuclear-radiation

Question 9

How long does it take for thyroid cancer to develop following nuclear incidents?

Answer 9

4 years - several decades

Question 10

What is found on thyroid examination in the majority of thyroid cancers?

Answer 10

Palpable nodules

Question 11

Thyroid cancer is a chance finding following what procedure?

Answer 11

Thyroidectomy

for say hyperthyroidism secondary to Graves disease

Question 12

What is the most common type of thyroid cancer?

Answer 12

Papillary

Question 13

Papillary thyroid cancer spreads via which system?

Answer 13

Lymphatic system

Question 14

Papillary thyroid cancer is associated with what type of thyroiditis?

Answer 14

Hashimoto’s thyroiditis

Question 15

Follicular thyroid cancer tends to spread how?

Answer 15

Haematogenously

Question 16

How are suspected thyroid cancers investigated?

Answer 16

Ultrasound-guided FNA

Question 17

How is thyroid cancer initially treated?

Answer 17

Surgery

Question 18

What are the surgical options for treating thyroid cancer?

Answer 18

Lobectomy (including the isthmus)

Sub-total thyroidectomy

Total thyroidectomy

Question 19

Why isn’t lobectomy commonly carried out anymore?

Answer 19

Leaves half the thyroid intact, skewing thyroid function tests, drug doses etc.

Question 20

Depending on the risk calculated following surgery, what treatment is added on for thyroid cancer?

Answer 20

Thyroid remnant ablation (TRA)

using radioiodine

Question 21

Which risk stratification tool is used post-op in thyroid cancer?

Answer 21

AMES system

Age, Metastases, Extent of primary tumour, Size of primary tumour

Question 22

The AMES system divides post-op thyroid cancer patients into which two groups?

Answer 22

Low risk (cancer is/was confined to the thyroid)

High risk (spread outwith the thyroid)

Question 23

Which group of patients receive radioactive iodine treatment post-op?

Answer 23

High risk patients

Question 24

In which type of cancer would lymph node surgery be considered in addition to surgery and TRA?

Answer 24

Papillary

because it tends to spread lymphatically

Question 25

Why can patients become hypocalcaemic following thyroid surgery?

Answer 25

**Removal of parathyroid glands**

Question 26

Following thyroid surgery, what drug are patients discharged with?

Answer 26

**Thyroxine tablets** **Calcium** / recombinant **PTH** if parathyroids removed

Question 27

What test is carried out 3-6 months post-op to detect remnants of thyroid cancer?

Answer 27

**Whole body iodine scanning** to check for metabolically active cells, i.e cancer

Question 28

What needs to be elevated before a patient recieves a whole body iodine scan?

Answer 28

**TSH** to stimulate the metabolism of the cancer cells so they show up on the scan

Question 29

How are a patient's TSH levels raised prior to their whole body iodine scan?

Answer 29

**Stop taking their thyroxine for 2-4 weeks** (produces hypothyroid symptoms) **rhTSH injections** (don't need to stop thyroxine, but very expensive)

Question 30

If thyroid cancer is still active following surgery, what treatment is given to patients?

Answer 30

**Thyroid remnant ablation** using radioactive iodine

Question 31

Patients undergoing thyroid remnant ablation need to have a **(raised / suppressed)** TSH and undergo treatment **(at home / in isolation)**.

Answer 31

**raised TSH** **in isolation** (as their necks are really radioactive)

Question 32

What protein is used as a tumour marker for differentiated thyroid cancer?

Answer 32

**Thyroglobulin** as it is produced by papillary and follicular carcinomas thyroxine precursor

Question 33

Following treatment for differentiated thyroid cancer, you want to keep a patient's TSH (high / low).

Answer 33

**low** remember that it drives the cancer so **high to investigate**, **low post-op**

Question 34

What is an uncommon disease which can be caused by thyroid remnant ablation?

Answer 34

**Acute myeloid leukaemia (AML)** patients must be informed of this (1 : 10000 chance)

Question 35

How often are thyroid cancer patients followed up in clinic post-treatment?

Answer 35

**Every 2 months**

Question 36

Following treatment for thyroid cancer, what are patients put on?

Answer 36

**Thyroxine tablets**

Question 37

How can you tell if thyroid cancer has recurred?

Answer 37

**Raised thyroglobulin** **Metastasis to other parts of the body**

Question 38

If a patient has suspected recurrence of thyroid cancer, what test would you do?

Answer 38

Whole body iodine scan again

Question 39

What is the recurrence rate of differentiated thyroid cancer?

Answer 39

**30%**

Question 40

Apart from whole body iodine scanning, what other imaging may be used to identify areas of active cancer i.e in metastatic disease?

Answer 40

**PET scan**

Question 41

What is the general timeline of investigation and treatment in a patient presenting with DTC?

Answer 41

**Ultrasound-guided FNA** **Surgery** Whole body iodine scan --\> **Thyroid remnant ablation** **Thyroxine** and regular follow-up