Thyroid cancer Flashcards
what is differentiated thyroid cancer?
Refers to Papillary and Follicular variants
“Differentiated” refers to histological appearance but also to physiological characteristics
Differentiated features means a good prognosis compared to other solid tumours
what drives differentiated thyroid cancer?
TSH
what do most differentiated thyroid cancers uptake and secrete?
uptake iodine
secrete thryoglobulin
what is thyroid cancer strongly associated with?
radiation exposure
is thyroid cancer associated with smoking?
no
how do most people with thyroid cancers present?
with palpable nodules in the neck
what % of cases present with local or disseminated metastases?
5%
what is the most common thyroid cancer?
papillary
where does papillary thyroid cancer tend to spread?
via lymphatics
haematogenous spread to bones, lungs and liver
what condition is papillary thyroid cancer associated with?
hashimotos thyroiditis
what is the second most common thyroid cancer?
follicular
where is incidence of follicular cancer higher?
in regions of relative iodine deficiency
how does follicular thyroid cancer tend to spread?
haematogenously
how are these cancers investigated?
usually ultrasound guided FNA of the lesion
can sometimes involve excision biopsy of the lymphnode
what are the clinical predictions of malignancy in thyroid nodules?
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
what are the surgical treatment options?
Thyroid lobectomy with isthmusectomy
Sub-total thyroidectomy
Total thyroidectomy
who is classed as a low risk patient?
Younger patients ( men <40, women <50) with no evidence of metastases
Older patients with intrathyroidal papillary lesion or minimally invasive follicular lesion and primary tumour < 5cm and no distant metastases
20 year survival for AMES low risk group is claimed to be 99%
who is classed as a high risk patient?
All patients with distant metastases
Extrathyroidal disease in patients with papillary cancer
Significant capsular invasion with follicular carcinoma
Primary tumour > 5cm in older patients
20 year survival in AMES high risk is 61%
what is a thyroid lobectomy with isthmusectomy?
Papillary microcarcinoma ( < 1cm diameter)
Minimally invasive follicular carcinoma with capsular invasion only
Patients in AMES low risk group
when is a sub total or total thyroidectomy used?
DTC with extra-thyroidal spread
Bilateral / multifocal DTC
DTC with distant metastases
DTC with nodal involvement
Patients in AMES high risk group
what is involved in the post operative care after thyroid surgery?
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
when is whole body iodine scanning used?
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
