Thyroid Cancer Flashcards
(38 cards)
List 4 types of thyroid cancer and frequency of occurrence
- Follicular cell origin • Papillary (80%) • Follicular (15%) • Anaplastic (very rare) - C-cell (parafollicular cell) origin (5%) • Medullary carcinoma - Primary thyroid lymphoma (rare) - Primary thyroid sarcoma (rare)
How does age and sex relate to risk of malignancy ?
- Solitary nodules likely be malignant >60 yo and <30 yo
- higher risk in males
What is the typical presentation of a thyroid carcinoma
- Asymptomatic, palpable, solitary thyroid nodule
- Not painful or tender
- No hyper- or hypothyroidism
- Dx: FNA bx
Identify the signs and symptoms associated with thyroid malignancy
- Nodular growth
- Rapid growth: ominous sign
- Hard and fixed nodule
Describe the common findings on physical examination of a patient with thyroid cancer
- Should include thorough head and neck exam, careful attention to thyroid gland and cervical soft tissue, indirect laryngoscopy
- Solitary nodules can range from soft to hard
- Hard and fixed: more suggestive of malignancy than supple and mobile
- Firm cervical masses are highly suggestive of regional lymph node metastases
- Vocal cord paralysis implies involvement of recurrent laryngeal nerve
What is the goal of a solitary thyroid nodule workup?
differentiate malignant from benign - determine who needs intervention vs. who needs serial monitoring
What are the components of a solitary thyroid nodule workup?
- History
- PE
- lab eval
- FNAB
- Imaging can be adjunct in select cases
What is the most important diagnostic tool in a solitary thyroid nodule workup?
FNAB
is the first intervention and determines the next step in nodule management
4 Possible results of FNAB
- Benign disease
- Malignant disease
- Indeterminate for diagnosis
- Non-diagnostic
What often occurs with repeated biopsies?
Up to 50% of repeated biopsies result in definitive dx
What often occurs with indeterminate or non-diagnostic results
despite repeat biopsy, can undergo lobectomy sx for tissue dx
What is f/u for non diagnostic results?
can be monitored clinically, and radioiodine scans can be useful for determining the functional status of the nodule (most hyperfunctioning nodules are benign)
What is action for malignant results?
- require surgical intervention
what type cancers are often positively IDed on FNAB alone?
Papillary thyroid carcinoma and MTC
what two cancers are very difficult to distinguish on FNAB alone? what should be done?
- follicular adenoma from follicular carcinoma
- Should undergo sx for thyroid lobectomy for tissue dx
- Require complete thyroidectomy if malignancy is discovered on review of pathology
- Some controversy regarding extent of thyroidectomy for particular pathologic diagnosis…
What is the role of serum TSH in the w/u of a thyroid nodule?
- Low suggests autonomously functioning nodule, typically benign
- Malignant dz cannot be ruled out on basis of low or high TSH levels
What is the role of serum calcitonin in the w/u of a thyroid nodule?
Elevated: highly suggestive of medullary thyroid carcinoma
What are the three imaging studies used to dx thyroid cancer?
- Neck US
- Thyroid radioiodine imaging
- Neck CT/MRI
What is the role of Neck US in dx of thyroid cancer?
- MC modality to eval thyroid dz
- Limited usefulness for distinguish btwn malignant and benign nodules
- Per American Thyroid Association, is most important imaging modality in eval of thyroid cancer. Should be used routinely to assess primary tumor and all associated cervical lymph node basins preoperatively
What is the role of thyroid radio iodine imaging in the dx of thyroid cancer?
Determine functional status of a nodule but cannot exclude carcinoma
What is the role of neck CT/MRI in the dx of thyroid cancer?
- Avoid iodinated contrast agents
- Eval soft-tissue extension of large or suspicious thyroid masses into neck, trachea, esophagus. To assess metastases to cervical lymph nodes
- No role in routine management of solitary thyroid nodules
Describe the risk factors for thyroid papillary carcinoma
- MC thyroid malignancy
- F>M
- Mean age 34-40
List the metastatic sites for thyroid papillary carcinoma
- Has a propensity to spread to cervical lymph nodes (1/3 of pts at presentation of cancer have clinically evident lymph node metastases)
- 5-10% develop distant metastases, MC lungs and bone
Outline the treatment of thyroid papillary carcinoma
- Total thyroidectomy (GS)
• Lobectomy also an option if <4 cm, pro is reduced risk of complications - +/- Radioactive iodine if TSH is elevated
• Thyroid remnant ablation/treatment - Levothyroxine at a dose that suppresses plasma TSH to below normal range – inhibits growth of residual tumor cells
- Lifelong monitoring with plasma thyroglobulin and neck US