Thyroid cancer

Question 1

what is differentiated thyroid cancer?

Answer 1

Refers to Papillary and Follicular variants
“Differentiated” refers to histological appearance but also to physiological characteristics
Differentiated features means a good prognosis compared to other solid tumours

Question 2

what drives differentiated thyroid cancer?

Answer 2

TSH

Question 3

what do most differentiated thyroid cancers uptake and secrete?

Answer 3

uptake iodine
secrete thryoglobulin

Question 4

what is thyroid cancer strongly associated with?

Answer 4

radiation exposure

Question 5

is thyroid cancer associated with smoking?

Answer 5

no

Question 6

how do most people with thyroid cancers present?

Answer 6

with palpable nodules in the neck

Question 7

what % of cases present with local or disseminated metastases?

Answer 7

5%

Question 8

what is the most common thyroid cancer?

Answer 8

papillary

Question 9

where does papillary thyroid cancer tend to spread?

Answer 9

via lymphatics
haematogenous spread to bones, lungs and liver

Question 10

what condition is papillary thyroid cancer associated with?

Answer 10

hashimotos thyroiditis

Question 11

what is the second most common thyroid cancer?

Answer 11

follicular

Question 12

where is incidence of follicular cancer higher?

Answer 12

in regions of relative iodine deficiency

Question 13

how does follicular thyroid cancer tend to spread?

Answer 13

haematogenously

Question 14

how are these cancers investigated?

Answer 14

usually ultrasound guided FNA of the lesion
can sometimes involve excision biopsy of the lymphnode

Question 15

what are the clinical predictions of malignancy in thyroid nodules?

Answer 15

New thyroid nodule age <20 or >50
Male
Nodule increasing in size
lesion > 4cm in diameter
History of head and neck irradiation
Vocal cord palsy

Question 16

what are the surgical treatment options?

Answer 16

Thyroid lobectomy with isthmusectomy
Sub-total thyroidectomy
Total thyroidectomy

Question 17

who is classed as a low risk patient?

Answer 17

Younger patients ( men <40, women <50) with no evidence of metastases
Older patients with intrathyroidal papillary lesion or minimally invasive follicular lesion and primary tumour < 5cm and no distant metastases
20 year survival for AMES low risk group is claimed to be 99%

Question 18

who is classed as a high risk patient?

Answer 18

All patients with distant metastases
Extrathyroidal disease in patients with papillary cancer
Significant capsular invasion with follicular carcinoma
Primary tumour > 5cm in older patients
20 year survival in AMES high risk is 61%

Question 19

what is a thyroid lobectomy with isthmusectomy?

Answer 19

Papillary microcarcinoma ( < 1cm diameter)
Minimally invasive follicular carcinoma with capsular invasion only
Patients in AMES low risk group

Question 20

when is a sub total or total thyroidectomy used?

Answer 20

DTC with extra-thyroidal spread
Bilateral / multifocal DTC
DTC with distant metastases
DTC with nodal involvement
Patients in AMES high risk group

Question 21

what is involved in the post operative care after thyroid surgery?

Answer 21

Calcium checked within 24 hours
Calcium replacement initiated if corrected Calcium falls below 2 mmol/l
Intravenous calcium for calcium levels below 1.8 mmol/l or if symptomatic
Patient discharged on T3 or T4

Question 22

when is whole body iodine scanning used?

Answer 22

Used in patients who have undergone sub-total or total thyroidectomy
Usually performed 3-6 months post-op
T4 stopped 4 weeks prior to scan
T3 stopped 2 weeks prior to scan
rhTSH is far better as no need to stop T3/T4
TSH should be greater than 20 for best results