Thyroid Cancer

Question 1

Histological Classification (40

Answer 1

papillary
follicular
medullary
anaplastic

Question 2

Differentiated thyroid cancer (DTC)

Answer 2

Refers to papillary and follicular variants

Take up iodine
Secrete thyroglobulin

TSH driven

Question 3

DTC incidence and prevalence

Answer 3

2females: 1 male

Uncommon in childhood
In females, rate increase from 15-40 then plateau
In males, steady increase with age

Question 4

DTC Epidemiology

Answer 4

Strong association with radiation exposure

lower incidence in Afro-americans

no association with diet, other malignancies, FHx, smoking or lifestyle factors

Question 5

DTC presentation

Answer 5

Palpable nodules

Chance findings on histological section of thyroidectomy tissue

local or disseminated mets (~5%)

Question 6

Papillary thyroid cancer

- Spread

Answer 6

Commonest histological type

Tend to spread via lymphatics

haematogenous spread to lungs, bone, liver and brain

Question 7

Papillary thyroid cancer association

Answer 7

hashimotos thyroiditis

Question 8

Papillary thyroid cancer prognosis

Answer 8

Good prognosis

-10 year mortality <5%

Question 9

Follicular Carcinoma incidence

Answer 9

incidence slightly higher in regions of relative iodine deficiency

Question 10

Follicular carcinoma spread & prognosis

Answer 10

Tend to spread haematogenously
Lymphatic spread very rare

Similar prognosis to papillary

Question 11

DTC Investigations

Answer 11

US guided FNA of lesion
Can involve excision biopsy of lymph node

if vocal cord palsy suspected clinically
- pre-operative laryngoscopy

No role for isotope thyroid scan or CT/MRI

Question 12

Clinical Predictors of Malignancy

Answer 12

new thyroid nodule age <20 or >50 
male
nodule increasing in size 
lesion >4cm in diameter 
History of head. neck irradiation 
Vocal cord palsy

Question 13

DTC Management

Answer 13

Surgical + Thyroid remnant ablation

Question 14

DTC Operative management

Answer 14

Surgery- treatment of choice.

Thyroid lobectomy with isthmusectomy
Subtotal thyroidectomy
Tootal thyroidectomy

Question 15

DTC Risk Stratification Post-Op

Answer 15

AMES

• Age
• metastases
• Extent of primary tumour
• Size of primary tumour

Question 16

AMES low risk

Answer 16

Younger patient (M<40 and F<50) with no evidence of mets

Older patient with

• Intrathyroidal papillary nodule
• minimally invasive follicular lesion
• primary tumour <5cm
• no distant mets

Question 17

AMES high risk

Answer 17

Distant mets
Papillary caner+ extra thyroidal disease
Follicular+ Significant capsular invasion
Primary tumour >5cm in older patients

Question 18

Thyroid Lobectomy with Isthmusectomy

Answer 18

Papillary micro carcinoma (<1cm)

minimally invasive follicular carcinoma with capsular invasion only

Patients in AMES low risk

Question 19

Sub-total/ Total thyroidectomy

Answer 19

DTC with extra-thyroidal spread

Bilateral / multifocal DTC

DTC with distant mets

DTC with nodal involvement

Patients in AMES high risk

Question 20

Lymph node surgery

Answer 20

Macroscopic lymph node disease
- nodal clearance

Papillary tumours
- central compartment clearance and lateral lymph node sampling

Follicular Cancer
-Central lymph node clearance

Question 21

DTC post-operative care

Answer 21

Calcium checked with 24hrs
Calcium replacement if <2mmol/L
IV calcium if <1.8mmol/l or symptomatic
Patient discharged on T3 or T4

Question 22

Whole Body iodine scanning

Answer 22

patient undergone thyroidectomy

3-6 months post-op

T4 stopped 4 weeks prior
T3 stopped two weeks prior

No need to stop T3/T4 for rhTSH

TSH> 20 for best results

Result of scan inform treatment decision

Question 23

Thyroid Remnant ablation

Answer 23

Pre-treated with rhTSH

2 or 3 GBq capsule of I-131 administered

Discharged when count rate <500cps at 1m

Side effects

• sialadenitis
• sore throat

follow up
-patient maintained on T4
Thyroglobulin used as ‘tumour marker’