Thyroid Cancer Flashcards
Thyroid Anatomy:
The bulk of the gland is located immediately anterior and inferior to the thyroid cartilage.
TRUE or FALSE?
True
Thyroid Anatomy:
50% of individuals have a pyramidal lobe that extends
superiorly from the central aspect of the gland, which is a remnant of the gland’s
embryologic origin.
Name this origin.
thyroglossal duct.
Thyroid Anatomy:
Arterial supply (2)
superior thyroid arteries (branches of the external carotid arteries)
inferior thyroid arteries (branches of the thyrocervical trunk from the subclavian arteries)
Thyroid Anatomy:
Venous drainage (3)
paired superior and middle thyroid veins (drains to the IJV)
inferior thyroid veins (drains to the subclavian and innominate veins)
Thyroid Anatomy:
First-echelon nodes
level 6
(central/visceral compartment)
containing the paralaryngeal, paratracheal, and prelaryngeal (delphian) nodes.
Thyroid Anatomy:
Second-echelon nodes
levels 3 and 4,
level 7
and to a lesser extent, level 2
Thyroid Histology:
What is the structural and functional unit of the gland?
thyroid follicles (formed by numerous lobules)
Thyroid Histology:
What is the histology of the thyroid follicle?
single layer of cuboidal epithelium
Thyroid Histology:
What are the contents of the thyroid follicles?
thyroid follicular cells surrounding a central-lumen colloid, a substance rich in thyroglobulin.
Thyroid Histology:
What cells contain granules of calcitonin?
They are neural crest–derived cells.
parafollicular cells or C cells
Thyroid Histology:
The thyroid is incompletely surrounded by a connective tissue capsule.
TRUE or FALSE?
True.
What is the storage and transport form of thyroid hormone?
thyroxine, or 3,5,3’,5’ iodothyronine
or simply T4
What is the metabolicaly active form of thyroid hormone?
thyronine, or 3,5,3’ iodothyronine
or simply T3
Classifications of thyroid cancer:
What type of thyroid cancer arises from the parafollicular C cells of the thyroid?
MTC
medullary thyroid carcinoma
Classifications of thyroid cancer:
What are the two major subgroups of Differentiated Thyroid Carcinoma (follicular-derived)?
PTC and FC
Classifications of thyroid cancer:
The diagnosis of this differentiated (follicular-derived) carcinoma is entirely predicated on the presence of diagnostic nuclear feature and does not require invasive growth.
PTC
nuclear enlargement, hypochromasia, intranuclear cytoplasmic inclusions (nuclear pseudoinclusions), nuclear grooves, and distinct nucleoli.
Classifications of thyroid cancer:
The diagnosis of FC requires evidence of tumor invasion through the thyroid capsule.
TRUE or FALSE?
False
requires evidence of tumor invasion through the tumor (not the thyroid) capsule.
Classifications of thyroid cancer:
Orphan Annie Eyes
PTC.
After formalin fixation, nuclei may appear pale and
optically clear and resemble “Orphan Annie eyes.”
Classifications of thyroid cancer:
Differentiating between classic PTC, follicular PTC, and oncocytic PTC is important because the management and prognosis are different.
TRUE or FALSE?
False
Classifications of thyroid cancer:
What are the subtypes of PTC that have poor prognoses that sometimes are classified under poorly-differentiated carcinomas?
diffuse sclerosing
tall-cell
columnar
hobnail
Classifications of thyroid cancer, lets step up the confusion.
What is this subtype of differentiated carcinoma, previously classifed as a subtype of follicular carcinoma that is now to be regarded as a separate entity. It was formerly called oncocytic carcinoma (not to be confused with oncocytic variant of PTC)?
cells are large and contain abundant granular eosinophilic cytoplasm and can be found in both benign and other malignant lesions, however to make a diagnosis, they must make up at least 75% of the tumor.
Hurthle cell carcinoma.
Classifications of thyroid cancer:
Amyloid is a characteristic feature of which thyroid cancer?
MTC
Classifications of thyroid cancer:
What familial syndrome is associated with MTC?
multiple endocrine neoplasia (MEN) IIa and IIb
Classifications of thyroid cancer:
MTC originates from what cells?
parafollicular or C cells.
Classifications of thyroid cancer:
Iodine avidity/concentration:
Usually Concentrate Iodine to a Degree That May Be Curative
Papillary thyroid carcinoma
Classic
Follicular variant
Oncocytic variant
Follicular thyroid carcinoma
Classic
Classifications of thyroid cancer:
Iodine avidity/concentration:
Often Do NOT Concentrate Iodine to a Degree That Is Curative
Unfavorable variants of papillary thyroid carcinoma
Diffuse sclerosing
Tall cell
Columnar cell
Hobnail
Hurthle cell carcinoma
Classifications of thyroid cancer:
Iodine avidity/concentration:
Rarely Concentrate Iodine to a Degree That Is Curative
Poorly differentiated thyroid carcinoma: insular carcinoma
Classifications of thyroid cancer:
Iodine avidity/concentration:
Never Concentrate Iodine to a Degree That Is Curative
Anaplastic carcinoma
Medullary carcinoma
What is the most common presentation of thyroid cancer?
asymptomatic thyroid
nodule found incidentally by the patient or clinicians or on an imaging study
performed for other reasons
Management of thyroid cancer:
What are the initial imaging ancillary procedures you can request to assess thyroid nodules?
Neck US with doppler and
US FNA
Management of thyroid cancer:
Findings in CT that is likely associated with malignancy
mass with extrathyroidal
extension, lymph node metastases, or both
Management of thyroid cancer:
Describe the role of nuclear imaging in the treatment of thyroid cancer
☻
too long to place here.
I think you’re right.
Staging of thyroid cancer:
(AJCC 8th ed)
T1 (a and b)
T1a Tumor ≤1 cm in greatest dimension limited to thyroid
T1b Tumor >1 cm but ≤2 cm in greatest dimension limited to the thyroid
Staging of thyroid cancer:
(AJCC 8th ed)
T2
Tumor >2 cm but ≤4 cm in greatest dimension limited to the thyroid
Staging of thyroid cancer:
(AJCC 8th ed)
T3 (a and b)
T3a Tumor >4 cm limited to the thyroid
T3b Gross extrathyroidal extension invading only strap muscles (sternohyoid, sternothyroid, thyrohyoid, or omohyoid muscles) from a tumor of any size
Staging of thyroid cancer:
(AJCC 8th ed)
T4 (a and b)
T4a Gross extrathyroidal extension invading subcutaneous soft tissues,
larynx, trachea, esophagus, or recurrent laryngeal nerve from a tumor of any size
T4b Gross extrathyroidal extension invading prevertebral fascia or encasing the carotid artery or mediastinal vessels from a tumor of any size
Staging of thyroid cancer:
(AJCC 8th ed)
N0 (a and b)
N0a One or more cytologically or histologically confirmed benign lymph nodes
N0b No radiologic or clinical evidence of locoregional lymph node metastasis
Staging of thyroid cancer:
(AJCC 8th ed)
N1 (a and b)
N1a Metastasis to level VI or VII (pretracheal, paratracheal, or
prelaryngeal/delphian, or upper mediastinal) lymph nodes. This can be unilateral or bilateral disease.
N1b Metastasis to unilateral, bilateral, or contralateral lateral neck lymph nodes (levels I, II, III, IV, or V) or retropharyngeal lymph nodes
Staging of thyroid cancer:
(AJCC 8th ed)
Staging of Differentiated thyroid cancer
The maximum stage for < 55 years old
II
Staging of thyroid cancer:
(AJCC 8th ed)
Staging of Anaplastic thyroid cancer
N1 M0 is staged as?
IVB
Staging of thyroid cancer:
(AJCC 8th ed)
Staging of Anaplastic thyroid cancer
N1 M1 is staged as?
IVC
Staging of thyroid cancer:
(AJCC 8th ed)
Staging of Anaplastic thyroid cancer
Any T, N1, M0 is staged as?
IVB
Staging of thyroid cancer:
(AJCC 8th ed)
Staging of Anaplastic thyroid cancer
T1-3a, N0 is staged as?
IVA
therefore the earliest stage for anaplastic is stage IVA
Prognostic Factors in Thyroid Cancer:
According to the ATA and NCCN, microscopic margin status (positive margins) is not an important prognostic factor.
TRUE or FALSE?
True.
Prognostic Factors in Thyroid Cancer:
What is the most important prognostic factor?
histology
Prognostic Factors in Thyroid Cancer:
Children below <12 years old have better prognosis than young adults,
and young adults have a decreasing prognosis as age increases
TRUE or FALSE?
False.
Children below <12 have worse prognosis.
The latter half of the statement is true.
Prognostic Factors in Thyroid Cancer:
Distant metastases may be cured with I-131 therapy and most experience long-term survival.
TRUE or FALSE?
True.
Management of thyroid cancer:
What is the initial treatment for localized thyroid cancer of all histologies?
surgery
total thyroidectomy is the preferred oncologic procedure
Management of thyroid cancer:
What is the biological half-life of I-131 in thyroid and extrathyroidal tissues?
thyroid - 80 d
extrathyroidal - 12 d
Management of thyroid cancer:
Indications for EBRT for DTC.
Age > 18 with visible unresected neck diseased
UNIV OF FLORIDA
Most situations where surgery is not able to remove all visible tumor with acceptable morbidity but age is a factor
Because of the increased risk of complications from EBRT in young patients, we usually treat small-volume (<2 cm3) unresectable residual tumor in the neck in patients < 55 years old with I-131 without EBRT if the patient is I-131 naive.
We do not use EBRT if I-131 may be curative, or elevated Tg is the only sign of disease.
ATA
Recommendation 71 [C22]: EBRT is considered for locoregional recurrence that is not surgically resectable, in particularly in patients with no evidence of distant disease.
NCCN
Consider EBRT for gross disease that is unresectable and/or threatening vital structures.
EBRT is recommended for patients with gross residual or unresectable locoregional disease, except for patients < 45 years old with limited gross disease that is I-131 avid.
Management of thyroid cancer:
Indications for EBRT for DTC.
Age > 18 y:
Adjuvant treatment soon after thyroidectomy
AHNS
EBRT should not be used routinely as adjuvant therapy after complete resection of gross disease.
NCCN
No guidelines in the absence of unresectable disease
ATA
There is no role for routine adjuvant EBRT to the neck in patients with DTC after initial complete surgical removal of the tumor.
Univ of Florida
Most cases with stage T4 primary tumor or nodal metastases with extensive ENE, but age is a factor.
We do not use EBRT if I-131 may be curative, or elevated Tg is the only sign of disease.
Management of thyroid cancer:
Indications for EBRT for DTC.
Age > 18 y: After gross total resection of recurrence following initial therapy
AHNS
After complete resection, EBRT may be considered in select patients older than 45 y of age with a high likelihood of microscopic residual disease and a low likelihood of responding to I-131. This scenario may occur in the setting of gross extrathryoidal extension with revision surgery for persistent or recurrent disease.
ATA/NCCN
No guidelines in the absence of unresectable disease
Univ of Florida
Same as for adjuvant EBRT after thyroidectomy
Management of thyroid cancer:
RT doses for anaplastic thyroid cancer?
with gross disease.
CTV 70 Gy at 2 Gy = Visible residual tumor and/or postoperative areas with close margin or
extranodal extension, plus a 1-cm margin edited for anatomic boundaries to tumor spread.
CTV 63 Gy at 1.8 Gy = Dissected nodal stations with pathologically positive nodes
CTV 56 Gy at 1.6 Gy = Undissected nodal stations that we judge to be at > 10% risk of
recurrence
PTVs = CTV + 0.3 cm
