thyroid cancer

Question 1

what types of thyroid cancer are differentiated?

Answer 1

papillary and follicular

Question 2

do differentiated tumours have better or worse prognosis than other solid tumours?

Answer 2

better

Question 3

what do the majority of thyroid cancers present with?

Answer 3

palpable nodules- small percentage are chance findings

Question 4

where does papillary thyroid cancer commonly spread?

Answer 4

via lymphatics
rare haematogenous spread to lungs, bone, liver, brain

Question 5

what disease is papillary thyroid cancer associated with?

Answer 5

hashimoto’s thyroiditis

Question 6

where do follicular thyroid carcinomas commonly spread?

Answer 6

haematogenously

Question 7

what investigations are done for thyroid cancer?

Answer 7

ultrasound guided FNA of lesion- can differentiate between cancerous and benign nodules
can do excision biopsy of lymph node

Question 8

what are the clinical predictors for malignancy?

Answer 8

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 9

what is the treatment of choice for thyroid cancer?

Answer 9

surgery
surgical options are:
Thyroid lobectomy with isthmusectomy
Sub-total thyroidectomy
Total thyroidectomy

Question 10

when do you use thyroid lobectomy with isthmusectomy?

Answer 10

-Papillary microcarcinoma ( < 1cm diameter)
-Minimally invasive follicular carcinoma with capsular invasion only
-low risk patients

Question 11

when do you do a sub-total or total thyroidectomy?

Answer 11

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

Question 12

what is the post operative care after thyroid surgery?

Answer 12

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 13

when do you use full body iodine scanning?

Answer 13

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

Question 14

what is thyroid remnant ablation?

Answer 14

radiation treatment post surgery to suppress TSH and prevent recurrence
lots of radiation so have to have no contact with children or pregnant people for 4 weeks

Question 15

what is the recurrence rate for thyroid cancer?

Answer 15

30%