Thyroid Cancer Flashcards
what are the 5 histological classes of thyroid cancer?
- papillary
- follicular
- medullary
- anaplastic
- other
what are the 2 most common types of thyroid cancer?
papillary
follicular
what does a medullary thyroid cancer secrete?
calcitonin
what is the prognosis like of anapaestic thyroid cancer?
very poor
almost anyone who gets it dies within a few months
what does the term differentiated thyroid cancer refer to?
papillary & follicular variants
what does the term differentiated refer to?
histological appearance but also to physiological characteristics that allow diagnosis & treatment
what do most DTCs take up?
iodine
what do most DTCs secrete?
thyroglobulin
what are DTCs driven by?
TSH
is thyroid cancer common or not?
not common at all
does DTC have higher or lower incidence in afro-americans?
lower
what does DTC have a strong association with?
radiation e.g. treatment for lymphoma
how do the majority of DTCs present?
palpable nodules
what is the commonest histological type of thyroid cancer?
papillary
how does papillary thyroid cancer commonly spread?
via lymphatics
where would a haematogenous spread likely go?
lungs
bone
liver
brain
which thyroiditis is papillary thyroid cancer associated with?
hashimoto’s thyroiditis
what is the second commonest type of DTC?
follicular carcinoma
in which regions is the incidence of follicular carcinoma slightly more common?
regions of relative iodine deficiency
follicular carcinoma is spreads more commonly through which system?
haematogenously
in which type of DTC are you more likely to find lymph node enlargement?
papillary
what is the most common 1st line investigation for suspected thyroid cancer?
ultrasound guided FNA of the lesion
FNA
fine needle aspiration
what is the 2nd most common investigation of thyroid cancer?
excision biopsy of lymph node
what investigation should a patient be sent for pre-operatively if vocal cord palsy is suspected clinical?
pre-operative laryngoscopy
what are the surgical options for thyroid cancer treatment?
thyroid lobectomy with isthmusectomy
sub-total thyroidectomy
total thyroidectomy
how is surgical risk assessed?
AMES Age Metastases Extent of primary tumour Size of primary tumour
what is the most common complication of thyroid surgery & why?
hypocalcaemia due to inadvertent removal of all parathyroid glands
in which patients is whole body iodine scanning used in?
patients who have undergone sub-total or total thyroidectomy
how long after an operation is whole body iodine scanning usually performed?
3-6 months
for how long before the whole body iodine scan is T4 stopped?
4 weeks prior
for how long before the whole body iodine scan is T3 stopped?
2 weeks prior
what level should TSH be at for whole body iodine scanning to be effective?
greater than 20
rhTSH
genetically made TSH aka thyrogen
what is the benefit of hTSH injections?
gives short rise in TSH levels without stopping thyroxin, no change in symptoms
where is iodine normal taken up in the body?
salivary glands
stomach
bladder (excreted via kidney)
TRA
thyroid remnant ablation
when is TRA used?
in those with residual disease
which protein can be used as a thyroid tumour marker after TRA?
thyroglobulin
which cells produce thyroglobulin?
normal thyroid cells
DTC cells
what should the serum thyroglobulin level be in a patient who is cured of DTC?
undetectable
why would you do TRA?
to ablate residual thyroid tissue in order to destroy occult microfoci
what are patient’s biochemical picture like after TRA?
hyperthyroid
at what level does hyperthyroidism after TRA become risky?
30+
what does hyperthyroidism of 30+ increase the risk of?
osteoporosis & AF
what is the absolute contraindication to TRA?
pregnancy
