Differentiated Thyroid Cancer(DTC) Management

Question 1

what types of thyroid tumour are included by differentiated thyroid cancer(DTC)

Answer 1

papillary and follicular carcinomas

Question 2

what is the treatment method of choice in DTC

Answer 2

surgery

Question 3

what are the main 3 surgical treatment of the DTC

Answer 3

thyroid lobectomy with isthmusectomy, sub-total thyroidectomy, total thyroidectomy

Question 4

what risk stratification is used for DTC in Ninewells

Answer 4

AMES(Age, Metastases, Extent of primary tumour, Size of primary tumour)

Question 5

describe a DTC that would be considered AMES low risk

Answer 5

younger patient with no evidence mets, older patient with intrathyroidal papillary or minimally invasive follicular + <5cm tumour + no mets

Question 6

describe a DTC that would be considered AMES high risk

Answer 6

distant mets all patients, extrathyroidal papillary, sig capsular invasion follicular, tumour >5cm older patients

Question 7

when would a thyroid lobectomy with isthmusectomy be used as treatment for DTC

Answer 7

papillary microcarcinoma(<1cm), minimally invasive follicular carcinoma with capsular invasion only, AMES low risk

Question 8

when would sub-total or total thyroidectomy be used as treatment for DTC

Answer 8

extrathyroidal spread, bilateral, distant mets, nodal involvement, AMES high risk

Question 9

what is current practice for lymph node surgery in papillary and follicular DTCs

Answer 9

papillary = central compartment clearance and lateral lymph node sampling 
follicular = central lymph node clearance

Question 10

describe the relevance of Ca2+ in post-operative DTC care

Answer 10

Ca checked within 24hrs, replacement initiated if corrected Ca fall <2mmol/l, IV Ca if <1.8mmol/l or symptomaitc

Question 11

in what patients is whole body iodine scan used

Answer 11

those who have had sub-total or total thyroidectomy

Question 12

when is whole body iodine scan usually performed and what needs to stop being taken prior

Answer 12

3-6 months post op, stop T3 2 weeks prior, stop T4 weeks prior to scan

Question 13

what level of TSH is best for whole body iodine scan results, and what does TSH level determine

Answer 13

TSH >20 for best results, sensitivity is determined by TSH levels elevated

Question 14

describe the process of whole body iodine scanning

Answer 14

rhTSH injection Monday/Tuesday, 2-4mCi I-131 Wednesday, scan Friday
(used to decide treatment)

Question 15

what is the reason for use of Thyroid Remnant Ablation(TRA) in DTC

Answer 15

to ablate residual thyroid tissue in order to destroy any remaining carcinoma in patients that have undergone surgery

Question 16

describe the process of Thyroid remnant ablation(TRA)

Answer 16

pre-treated with rhTSH, then given 2 or 3 GBq I-131(which is 200-300 x more than in whole body iodine scan)

Question 17

what protections are need for TRA and why

Answer 17

needed because patient is radioactive due to high amount of I-131
lead lined room, minimal/no contact with family/nurses, disposable cutlery, sheets etc.

Question 18

what can be used as a ‘tumour marker’ post TRA treatment

Answer 18

thyroglobulin(Tg)

should be measured pre-op too as not all patients are secretors of Tg

Question 19

what are patients maintained on after TRA and what is the aim of treatment

Answer 19

maintained on T4, aim to get TSH <0.1mU/l and keep free T4 <25

Question 20

what are the long term effects/side effects of TRA

Answer 20

very few side effects = sialedinits, sore throat

long term = small increase risk of AML(leukaemia), but no risk tumours/infertility/genetic changes

Question 21

what is thee recurrence rate for DTCs

Answer 21

30%

Question 22

how can recurrent DTC be identified

Answer 22

by rising Tg or imaging(whole body iodine scan)