Differentiated Thyroid Cancer Flashcards
Some epidemiological facts regarding papillary thyroid cancer
(risk factors, prognosis)
- 70-80% of thyroid carcinomas
- peak incidence 30s-40s
- most important risk factor = childhood radiation exposure
- other risk factors: family history, Werner/Cowden syndrome, Carney complex, familial polyposis
- 95% ten year survival rate
Papillary thyroid cancer- histological appearance (pathognomonic signs)
calcifications
psammoma bodies (concentric lamellated calcific structures)
squamous metaplasia & fibrosis
Histological variants of PTC?
classical PTC follicular PTC tall cell columnar hobnail (tends to occur in older patients, prognosis less favourable)
What % of people with PTC have lymphatic mets? What are the two most common sites of lymphatic mets?
30-40% of people
3-5% metastatic at time of diagnosis
lungs and bones are two most common sites
Is lymphadenectomy routinely performed for PTC?
Nope
Intra-operatively checking for suspicious LN- then can take out if suspicious
What is the most common genetic mutation seen in PTC?
BRAF V600E
V= valine E= glutamic acid
20% of patients with PTC have RET proto-oncogene
What other conditions is RET proto-oncogene associated with?
pheochromocytoma, FMTC, Hirschsprung’s disease
According to 2015 ATA guidelines, what are the recommendations for surgery based on size of tumour?
> 4 cm: total thyroidectomy
1-4 cm: total thyroid vs lobectomy
<1 cm: observe unless there are high risk features (extrathyroidal extension, lymphatic mets, etc)
What is a thyroid microcarcinoma?
papillary thyroid cancers <1 cm in size
-may be multifocal and are usually clinically silent until thyroidectomy for another indication
Epidemiology facts about follicular carcinoma.
10-20% of thyroid cancers
- females>males
- usually older population than PTC (40-60s)
Is radiation a risk factor?
What is the best prognostic factor?
Radiation is NOT risk factor
Age is best prognostic factor
Genetic mutations associated with Follicular carcinoma
PAX 8/PPARgamma genetic mutations
Most common route of spread for follicular thyroid cancer?
hematogenous
F - far away
LN spread in 10% of cases only
>80% of follicular carcinomas will take up iodine
What is a minimally invasive follicular carcinoma?
follicular neoplasms that capsular invasion but no vascular invasion
Hurthle cell carcinoma
5% of all thyroid carcinomas
- likely follicular origin, considered DTC
- less than 10% of HCCs take up iodine
Management of Hurthle cell carcinoma (HCC)
diagnostic thyroid lobectomy at minimum
usually advocate for total thyroid
Indications for total thyroidectomy in Hurthle cell carcinoma
- DTCs >4 cm in size
- extrathyroidal extension
- regional or distant mets
- contralateral nodules/prior irradiation/familial DTC
- patient preference
What is the most common tumour to metastasie to thyroid gland?
Renal cell carcinoma
Other less common primaries: breast, lung, GI tract, melanoma, sarcoma
What are some prognostic scoring systems for thyroid malignancy?
AGES, AMES, MACIS
AGES A- age (low risk if women <50 years, men <40 years) *most important prognistcator G- grade E- extrathyroidal disease S- size of tumour (>4 cm bad)
AMES A- age M- mets E- extrathyroidal invasion S- size of tumour
MACIS M- mets A- age C- completeness of resection I- invasion of extrathyroidal structures S- size of tumour
How is age incorporated into TNM system?
if patient is less than 45 years old and does not have mets = Stage I (still favourable prognosis if younger)
What is the follow-up protocol after thyroidectomy for recurrent thyroid cancer?
Low risk:
Annual:
-physical exam
-Neck ultrasound at 6-12 months then frequency depends on patient factors
-TSH levels
-serum Tg and anti-Tg levels (if total thyroidectomy) q12-24 months
High risk:
same stuff as above, except do the Tg and anti-Tg levels q6-12 months instead
