Thyroid Cancer1 Flashcards
What is the lifetime risk for developing thyroid cancer in women and men?
The lifetime risk of developing thyroid cancer in the United States is estimated to be 0.8% for women and 0.3% in men.ﾠ
How is thyroid cancer categorized?
It is categorized into follicular cell-derived and non-follicular cell derived variants.
Follicular cell derived malignancies include papillary thyroid cancer, follicular cancer, Hurthle cell cancer, andﾠanaplastic cancer.
Non-follicular cell derived malignancies include medullary thyroid cancer, lymphoma, and metastases.
What inherited syndromes are associated with thyroid cancer?
Multiple endocrine neoplasia (MEN) 2A and 2B
Isolated familial medullary thyroid cancer
Gardner syndrome
Familial adenomatous polyposis
Carney complex
Cowden syndrome
Familial nonmedullary thyroid cancer
In which patients, a fine needle aspiration is indicated?
Patient with nodules of 1 cm or larger and nodules smaller than 1 cm with suspicious sonographic features.
If a FNA identifies medullary thyroid carcinoma, what should be next step in management?
Obtain a baseline serum calcitonin level and screened the paitent for pheochromocytoma and hyperparathyroidism.
What is the overall 10-year survival rate for papillary thyroid cancer?
93%
What is the most common thyroid cancer associated with previous history of radiation?
Papillary thyroid cancer
In papillary thyroid canrcinoma, how common is to find cervical lymph node involvement?
Common and occurs in up to 50% of patients.
Why a total thyroidectomy can be considered an optimal therapy in patients with low-risk papillary thyroid carcinoma?
- Total thyroidectomy is associated with the lowest incidence of local and regional recurrence.
- It also allows for the most effective use of serum thyroglobulinﾠand radioiodine for detection of recurrent disease and high-dose radioiodine for treatment of metastatic disease.
- Total thyroidectomy also eliminates a 1% incidence of anaplastic dedifferentiation.
Mention the criteria for distinguishing a low-risk well-differentiated thyroid carcinoma.
Women < 4cm in diameter
Tumor confined to thyroid
No distant metastases
Mention the criteria for distinguishing a high-risk thyroid carcinoma?
Women >50 years Men >40 years Poorly differentiated tumor Tumor > 4cm in diameter Local invasion Distant metastases
A central neck dissection consists of?
Consists of removal of all lymph nodes and fibrous fatty tissue from the hyoid bone superiorly to the brachiocephalic artery inferiorly and between the common carotid arteries laterally. The prelaryngeal, pretracheal, and paratracheal lymph nodes, which comprise the level VI nodes, are removed.ﾠ
How the recommendations for central neck dissection from the American Thyroid Association (ATA) varies from the National Comprehensive Cancer Network (NCCN)?
The ATA recommends that a routine central neck dissection be considered for patients with papillary thyroid carcinoma, whereas the NCCN only recommends central neck dissection for grossly positive lymph node metastases. The rationale for prophylactic central neck dissection is that the likelihood of occult microscopic disease is high, and reoperation for a recurrence in the central neck may be associated with a high complication rate.ﾠ
What percentage of follocular thyroid patient have lymph node metastases?
less than 10%
What is the overall 10-year survival rate for follicular thyroid cancer?
85%
Of all the well differentiated thyroid cancers, which has the highest incidence of metastases?
Hurthle cell carcinoma
T/F: Hurthle cell carcinoma is radioresistant and has a worse prognosis than papillary or follicular thyroid carcinoma, with a 10 year survival rate of approximately 75%.
TRUE
Which patients should undergo radioiodine ablation and why is helpful?
Should be recommended for patients with incomplete tumor resection, extrathyroidal tumor spread, nodal or distant metastases, or aggressive histology (tall cell, columnar cell, or diffuse sclerosing carcinoma).
It helps to optimize the use of serum thyroglobulin and radioiodine whole-body scanning for detection of recurrent disease.
What is the preparation needed for the patient prior ablation therapy?
Patients are placed on short-acting triiodothyronine (T3) postoperatively, 25 ﾵg twice a day, to minimize the period of hypothyroidism. Two weeks before receiving iodine, T3 is discontinued, and the patient is placed on a low-iodine diet to maximize the uptake and retention of radioiodine by the remnant tumor cells. Prior to proceeding with radioiodine ablation, the patientﾒs serum TSH level should be greater than 30 ﾵIU/mL to enhance radioiodine uptake by the residual normal follicular cells and tumor cells.
What are the recommendations for the TSH level postoperatively in patients following radioiodine therapy?
Following radioiodine ablation, patients are started on levothyroxine 2 ﾵg/kg per day, and serum TSH is measured 5 to 6 weeks later. The goal is to maintain the serum TSH level between 0.1 to 0.5 ﾵIU/mL, for patients with high-risk differentiated thyroid cancer (DTC) who are free of disease, and between 0.3 to 2.0 ﾵIU/mL for patients with low-risk DTC. In patients with metastatic disease, maintain a serum TSH level less than 0.1 ﾵIU/mL.
What should included the long term follow up of with differentiated thyroid carcinoma?
Physical examination, serum TSH and basal thyroglobulin (Tg) levels, anti-Tgﾠantibody measurement, and neck ultrasound
How often the surveillance for DTC patients shoul be performed?
Surveillance should be performed every 6 months for 2 years and then annually, if the patient remains disease free.
In which thyroid cancer patients, external beam radiation may be indicated?
It is indicated for patients in whom complete surgical excision is not possible and for tumors that do not concentrate radioiodine. It may also be used for patients with extrathyroidal tumor spread and extracapsular lymph node spread because of a high likelihood of residual disease, and it is used for palliation of bone pain in patients with skeletal metastases and for unresectable brain metastases.
From which cells , medullarythyroid carcinoma arises from?
Parafollicular or C cells of the thyroid gland.ﾠ
What markers can be elevated on patients with medullary thyroid carcinoma?
Patients with MTC have elevated serum calcitonin levels and may also have elevated carcinoembryonic antigen (CEA) and calcitonin gene-related peptide (CGRP) levels.
What percentage of medullary thyroid carcinoma are sporadic?
70 to 80%
T/F: Sporadic medullary thyroid carcinoma is usually confined to one lobe of the thyroid gland, however, multicentric or bilateral disease can be present in 30% of patients.
TRUE
Which are the syndromes associated with medullary thyroid carcinoma (MTC) and which is the mutation associated with it?
MTC is familial in 20% to 30% of patients, occurring as part of MEN2A, MEN2B, or isolated familial MTC syndromes, all of which have an autosomal-dominant inheritance and result from germline mutations in theﾠRETﾠprotooncogene.
What are the findings of patients wityh MEN 2A syndrome?
Medullary thyroid carcinoma, Pheochromocytoma, Hyperparathyroidism, Lichen planus amyloidosis, Hirschsprung disease
What are the findings of patients wityh MEN 2B syndrome?
Medullary thyroid carcinoma, Pheochromocytoma, Muscuskeletal abnormality (marfanoid habitus, pes cavas, pectus excavatum), Mucosal neuromas of the lips, tongue, and conjunctiva, Ganglioneuromatosis of the gastrointestinal tract, Medullated corneal nerve fibers
What is the most common familial syndrome associated with hereditary medullary thyroid carcinoma?
MEN 2A, 66%
What percentage of MEN 2A will develop medullary thyroid cancer (MTC), pheochromocytoma and hyperparathyroidism?
90% of gene carriers will develop MTC, 60% will develop unilateral or bilateral pheochromocytoma, and 15% to 30% will develop hyperparathyroidism.
How the diagnosis of medullary thyroid carcinoma is most commonly establisehed?
FNAB with immunohistochemical staining for calcitonin
What preoperative testing should be done on patients with medullary thyroid carcinoma?
- Testing for mutations in theﾠRETﾠprotooncogene.
- Serum calcitonin and CEA levels should be measured to determine if these are being produced by the tumor and to establish a baseline. High preoperative serum calcitonin levels correlate with tumor bulk, lymph node metastases, and systemic metastases, and high CEA levels are associated with a poorer prognosis.ﾠ
- Serum calcium level and either plasma free metanephrines or 24 hour urinary catecholamines and metanephrines measured prior to operation to screen for hyperparathyroidism and pheochromocytoma.
What is the mainstay of treatment for medullary thyroid carcinoma?
Total thyroidectomy with central compartment neck dissection +/- modified neck dissection
At what age, is prhophylactic thyroidectomy recommended in patients with MEN 2A?
Within the age of 3 to 5 in patients with RET germline mutations
At what age, is prhophylactic thyroidectomy recommended in patients with MEN 2B?
Recommended within the first year of life in patients withﾠRETﾠgermline mutations for MEN 2B.
For follow up in patient with history of medullary thyroid carcinoma, what diagnostic tests should be done if their calcitonin level is high?
CT of the chest, MRI of the liver, and bone scintigraphy.
What percentage of paitient will have regional or systemic at the time of anaplastic thyroid cancer diagnosis?
90%, most commonly in the lungs
T/F: All patients with Anaplastic Thyroid Carcinoma are classified as having stage IV.
TRUE. The median survival for ATC is approximately 5 to 6 months. Survival rates at 1 year are 20% to 35% and are 5% to 14% at 5 years.
What type are most of the primary thyroid lymphomas?
non-Hodgkin diffuse large B-cell type
Over 50% of thyroid lymphomas arise fromﾅ
Hashimoto thyroiditis
T/F: Thyroid lymphoma is NOT responsive to both chemotherapy and radiotherapy.
FALSE. Thyroid lymphoma is highly responsive to both chemotherapy and radiotherapy.
What are the poor prognostic factors for thyroid lymphoma?
Poor prognostic factors include advanced stage, a tumor greater than 10 cm, mediastinal involvement, age greater than 65, and dysphagia.
What is T1 thyroid CA?
Tumor < 2cm, limited to the thyroid
What is T2 thyroid CA?
Tumor >2 cm but <4 cm, limited to the thyroid
What is T3 thyroid CA?
Tumor >4 cm, limited to the thyroid
What is T4a thyroid CA?
Tumor of any size extending beyond the thyroid capsule to invade subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve
What is T4b thyroid CA?
Tumor invades prevertebral fascia or encases carotid artery or mediastinal vessels
What is N1 nodal disease in thyroid CA?
Regional lymph node metastasis
What is N1a nodal disease in thyroid CA?
Metastasis to level VI (pretracheal, paratracheal, and prelaryngeal/Delphian lymph nodes)
What is N1b nodal disease in thyroid CA?
Metastasis to unilateral or bilateral cervical or superior mediastinal lymph nodes
