Thyroid Cancer Flashcards by Mario Luna

Thyroid Anatomy:

The bulk of the gland is located immediately anterior and inferior to the thyroid cartilage.

TRUE or FALSE?

True

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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.

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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)

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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)

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Thyroid Anatomy:

First-echelon nodes

level 6
(central/visceral compartment)
containing the paralaryngeal, paratracheal, and prelaryngeal (delphian) nodes.

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Thyroid Anatomy:

Second-echelon nodes

levels 3 and 4,

level 7

and to a lesser extent, level 2

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Thyroid Histology:

What is the structural and functional unit of the gland?

thyroid follicles (formed by numerous lobules)

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Thyroid Histology:

What is the histology of the thyroid follicle?

single layer of cuboidal epithelium

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Thyroid Histology:

What are the contents of the thyroid follicles?

thyroid follicular cells surrounding a central-lumen colloid, a substance rich in thyroglobulin.

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Thyroid Histology:

What cells contain granules of calcitonin?

They are neural crest–derived cells.

parafollicular cells or C cells

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Thyroid Histology:

The thyroid is incompletely surrounded by a connective tissue capsule.

TRUE or FALSE?

True.

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What is the storage and transport form of thyroid hormone?

thyroxine, or 3,5,3’,5’ iodothyronine

or simply T4

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What is the metabolicaly active form of thyroid hormone?

thyronine, or 3,5,3’ iodothyronine

or simply T3

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Classifications of thyroid cancer:

What type of thyroid cancer arises from the parafollicular C cells of the thyroid?

MTC

medullary thyroid carcinoma

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Classifications of thyroid cancer:

What are the two major subgroups of Differentiated Thyroid Carcinoma (follicular-derived)?

PTC and FC

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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.

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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.

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Classifications of thyroid cancer:

Orphan Annie Eyes

PTC.

After formalin fixation, nuclei may appear pale and
optically clear and resemble “Orphan Annie eyes.”

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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

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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

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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.

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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

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