Thyroid/Thyroid cancer Flashcards
ATA nodule criteria for biopsy
high - 1cm
intermediate - 1cm
low - 1.5cm
very low - 2.0cm
TR nodule criteria for biopsy
TR 3 - 2.5cm
TR 4 - 1.5cm
TR 5 - 1.0cm
which Bethesda do we send for Thyroseq
Bethesda 3,4,5
Bethesda categories
1 - nondiagnostic 2- benign 3 - AUS/FLUS 4 - follicular neoplasm 5 - suspicious 6 - malignant
malignancy risk in high suspicion nodules
70-90%
malignancy risk in intermediate suspicion nodules
10-20%
malignancy risk in low suspicion nodules
5-10%
malignancy risk in very low suspicion nodules
<3%
malignancy risk in benign nodules
< 1%
high risk US features
microcalcification irregular margin taller than wide ETE interrupted rim calcification
malignancy risk of AUS/FLUS (Bethesda 3)
5-15%
malignancy risk of follicular neoplasm (Bethesda 4)
15-30%
malignancy risk of benign nodule (Bethesda 2)
0-3%
which Bethesda category is Hurthle cell neoplasm
Bethesda 4
repeated nondiagnostic FNA with high risk features
surgery or close US observation
pathologic criteria for sufficient thyroid FNA
6 groups of well-visualized follicular cells, each containing at least 10 well-preserved epithelial cells
malignancy risk in nondiagnostic samples
low
appropriate operation for indeterminant thyroid nodules
lobectomy
high suspicion nodule with negative FNA
repeat FNA within 12 months
intermediate nodules with negative FNA
repeat US 12-24 months with repeat FNA if > 50% volumetric growth
very low suspicion nodule with negative FNA
repeat US 24 months
risk of thyroid cancer after 2 negative FNA
essentially 0%
risk of false negative FNA
3%
what % of adults have thyroid nodules
50%
recommendation for thyroid nodules with suspected iodine deficiency
150 mcg daily iodine
management of thyroid nodules > 4cm
symptomatic - surgery
FNA
negative FNA - surgery or follow
thyroid nodule discovered during pregnancy
FNA if euthyroid or hypothyroid
PTC diagnosed during pregnancy
if substantial growth or e/o lymph nodes - surgery if stable (ie no growth), surgery after delivery
suspicious lymph node size criteria for FNA
8-10mm in SHORTEST dimension
absolute criteria of total thyroidectomy
thyroid cancer > 4cm
gross ETE
clinically apparent metastatic disease to nodes or distant sites
surgery for 1-4cm thyroid cancers
lobectomy or total thyroidectomy
therapeutic central neck dissection for which patients
clinically involved central nodes
prophylactic central neck dissection (ipsilateral or bilateral) should be considered in which patients
PTC with no clinical nodes who have advanced primary tumors (T3 or T4), or clinically involved lateral neck nodes
who does NOT need prophylactic central neck dissection
small (T1 or T2) tumors, noninvasive, clinically node-negative PTC, and for most follicular cancers
who should have therapeutic lateral neck lymph node dissection
ONLY biopsy-proven metastatic lateral cervical adenopathy
surgery for most follicular carcinomas
lobectomy
role of RAI ablation of remaining lobe in lieu of completion thyroidectomy
not recommended
diurnal pattern of TSH
highest values in late afternoon/evening
binding globulins for thyroid T4/T3
TBG
transthyretin
albumin
what percentage of T4 and T3 are bound
99.7 % +
two different assays for free hormone testing
analogue (cheaper, easier) equilibrium dialysis (not affected by serum binding proteins)
deiodinase D1 converts T4 to T3 in which organs
liver, kidney
deiodinase D2 converts T4 to T3 in which organ
brain
reverse T3 (RT3) affinity for the T3 receptor
100x less than T3
major disorders of thyroid hormone binding proteins
pregnancy
estrogen use
congenital TBG excess
familial dysalbuminemic hyperthyroxinemia
what is familial dysalbuminemic hyperthyroxinemia
inherited disorder in which albumin has enhanced affinity for T4, resulting in increased TOTAL T4 but not T3
role of T3 resin uptake measurement
helps distinguish protein binding disorders from true thyroid disease (inversely proportional to the protein binding capacity)
t3 resin uptake in hyperthyroidism
high
t3 resin uptake in hypothyroidism
low
two conditions where thyroglobulin can be useful
thyroid cancer
thyroiditis
effect of biotin on thyroid function tests
low TSH
high T4
looks like hyperthyroidism
when to suspect HAMA (heterophile ab) interference
abnormal TFTs that don’t fit clinical scenario
indications to treat subclinical hyperthyroidism
age > 65 years TSH <0.1 symptomatic bone disease/afib 0.1-0.4 can be considered for therapy
when to repeat thyroid US for 1cm very low risk thyroid nodules
either no follow up, or 2 years
initial surgical procedure for differentiated thyroid cancer with tumor > 4cm?
total thyroidectomy
initial surgical procedure with clinically apparent nodal mets, distant mets, or with gross extrathyroidal extension?
total thyroidectomy
initial surgical procedure for thyroid cancer > 1cm and < 4cm without ETE, and without nodal mets?
either lobectomy or total thyroidectomy
which patients should have therapeutic central compartment dissection?
pts with clinically involved central nodes
which patients should be considered for prophylactic central-compartment neck dissection (ipsilateral or bilateral)?
PTC with clinically uninvolved central compartment nodes BUT T3 or T4 tumors or clinically involved lateral neck nodes
which patients do NOT need prophylactic central neck dissection?
small tumors (T1, T2), noninvasive, node-negative PTC and most follicular cancers
which patients should get lateral neck lymph node dissection?
biopsy proven nodal metastasis
which patients should be offered completion thyroidectomy?
those for whom total thyroidectomy would have been recommended had the diagnosis been available before initial surgery (ie gross ETE, nodal involvement)
T1a
tumor < 1cm, without ETE
T1b
1-2cm, without ETE
T2
2-4cm, without ETE
T3
> 4cm in thyroid, OR
any size tumor with minimal ETE (sternohyoid muscle, perithyroid soft tissues)
T4a
tumor of any size extending thyroid capsule to invade subQ tissue, larynx, trachea, esophagus, or recurrent laryngeal nerve
T4b
tumor of any size involving prevertebral fascia or encasing carotid artery or mediastinal vessels
N0
no metastatic nodes
N1a
mets to level 6 nodes
N1b
mets to nodes in all other levels
M0
no distant mets
M1
distant mets
patient with thyroid cancer on levothyroxine withdrawal for treatment of thyroid cancer who develops nausea, confusion, lethargy, weakness, headache
check sodium level
number and size of micrometastases that still qualify as low-risk thyroid cancer
< or = 5, less than 0.2mm in largest dimension
TSH goal for low-risk thyroid cancers
0.5-2.0
TSH goal for intermediate-risk thyroid cancers
0.1-0.5
TSH goal for high-risk thyroid cancers
< 0.1
most common cause of thyroid storm in a patient already on thionamide tx
medication noncompliance
rising calcitonin/CEA in MTC patient with negative imaging – where to look for mets
Liver MRI with contrast
MRI spine
FDG PET/DOTATATE can be considered but not used routinely
2 ways of differentiating destructive thyroiditis from Graves’
uptake/scan, serum thyroglobulin
Graves’ pt gets RAI, has worsening hyperthyroidism the following week. Likely diagnosis?
destructive thyroiditis due to RAI
Graves’ pt gets RAI, then develops hyperthyroidism again a month later. Likely diagnosis?
recurrent Graves’ due to insufficient RAI dose
Graves’ pt gets RAI, then becomes more hyperthyroid after. How to differentiate between thyroiditis and recurrent Graves’?
uptake/scan
Pt with PTC has rising Tg level, negative Tg Abs, and negative whole body scan and neck US. Next imaging test?
PET/CT
treatment for pregnant female with substantial volume of residual cancer
surgery in 2nd trimester
treatment for pregnant female with small thyroid cancer
surgery after delivery
most common immune checkpoint inhibitor side effect
hypothyroidism
