Thyroid Cancer

Question 1

Below what age is thyroid cancer rare?

Answer 1

25 yrs

Question 2

What are the 4 commonest histologies thyroid cancer?

Answer 2

Papillary
Follicular
Medullary
Anaplastic

PFMA

Question 3

Which thyroid cancers are well differentiated and have a good prognosis?

Answer 3

Papillary and follicular

Question 4

What is the relationship between follicular thyroid cancer and iodine levels?

Answer 4

Higher levels follicular cancer in areas of iodine deficiency

Question 5

Which type of thyroid cancers arise from C cells?

Answer 5

Medullary

Question 6

Which type of thyroid cancer should patients be teated for a germline gene mutation?

Answer 6

Medullary cancer all patients should be tested for RET mutations

Question 7

If FNA of the thyroid shows follicular histology what is the next step?

Answer 7

Hemithyroidectomy to get histology

FNA cant distinguish between follicular malignant or benign- need histology to distinguish

Question 8

What imaging should be avoided prior to radioiodine?

Answer 8

Iodinated contrast media

Question 9

Which bloods should be done medullary thyroid cancer?

Answer 9

Calcitonin

CEA

Question 10

Should serum thyroglobulin be measured in the workup of thyroid cancer?

Answer 10

Its of no diagnostic value unless thyroid has been removed

Question 11

How to decide between hemi and total thyroidectomy?

Answer 11

Differentiated thyroid cancer
less than or = 1cm 
does not extend beyond capsule 
No LN 
No VI 
Not familial disease

Question 12

Recurrent laryngeal nerve injury with total thyroidectomy?

Answer 12

1-5%

Question 13

When to do prophylactic central neck node dissection?

Answer 13

> 4cm tumour

Extrathyroid disease

Question 14

A patient has thyroid cancer which secretes calcitonin and CEA, what kind is it?

Answer 14

Medullary

Question 15

Tell me about medullary thyroid cancer

Answer 15

Sporadic form peak age 50-60
Slightly more common in women 1.5:1
Associated with MEN 2 and 3 (AD, RET mutations)
Measuring post operative calcitonin can help tell risk of residual/ metastatic disease
If post op calcitonin is more than 150pg/ml look for locoregional or distant disease
A calcitonin doubling time of more than 2 years is a good sign

Question 16

In which type of thyroid cancer does the calcitonin level dictate the extent of surgery?

Answer 16

Medullary
Pre op 20 pg/ml only need a total thryoidectomy
200-500 do a contralateral lateral neck dissection!
Mediastinum only explored for imaging showing disease