Thyroid Flashcards
Initial workup of a thyroid nodule
- H&P
- TSH
- US
Thyroid Nodule (not neck mass) Differential
- Benign
- Colloid containing cyst
- Thyroid adenoma
- Hyperplastic nodule
- Thyroiditis
- Malignant
- Papillary
- Follicular
- Medullary
- Anaplastic
- Hürthle
Suspicious sonographic findings of the thyroid
- Hypoechoic
- Microcalcifications
- Extrathyroidal extensions/Infiltrative margins
- Irregular margins
- Taller than wide
- Lymph node involvement
Bethesda Criteria
Two big risk factors for thyroid malignancy
- Hx of neck radiation
- Fm hx of thyroid cancer or endocrine tumors
Familial Syndromes of Thyroid Disease
Preoperative workup in clinic for thyroid carcinoma
History:
- Focus on risk factors (h/o radiation; family hx, previous neck surgery)
Physical Exam:
- Focused neck exam (size, tracheal deviation, substernal extension, LN)
- Voice quality and volume
Preoperative labs and imaging in thyroid carcinoma
Labs
- TFT for all
- DTC - TSH, thyroglobulin, antithyroglobulin antibodies
- MTC - CEA, calcitonin
Imaging
- US thyroid & neck for LN
- +/- CT/MRI (for locally advanced disease or vocal cord paresis)
Other test
- +/- Laryngoscopy (vocal complaints/abnormalities, prior neck surgery/radiotherapy)
What special test can be performed with thyroid carcinoma?
Molecular Marker Testing
- Aid in risk-stratification
- Multiple tests available
- Afirma looks at 167 genes (BRAF, RAS, RET, etc.)
In thyroid carcinoma, what is the T staging?
T1
- 0-2 cm
T2
- >2-4 cm
T3
- >4 cm
- In MTC, includes extrathyroidal extensions
T4
- Gross extrathyroidal extension beyond strap muscles
In thyroid carcinoma, what is the N staging?
N0
- No nodal involvement
N1
- Nodal involvement
What is unique about Staging in DTC of the thyroid?
- Age < 55 can only have stage I or II
- 10 year survival >85%
What is unique about Staging in anaplastic carcinoma of the thyroid?
All anaplastic carcinoma is Stage IV be definition
PTC Surgical Treatment
SAFE ANSWER: IF >1 CM, TOTAL THYROIDECTOMY +/- therapeutic LN dissection for known disease only
- Can consider lobectomy if ALL:
- No prior radiation
- No distant mets
- No LN disease
- No extrathyroidal extension
- Tumor size 1-4 cm
- Active surveillance vs lobectomy
- <1 cm and LN negative
What are the pros and cons of total thyroidectomy vs lobectomy in PTC?
Pros of total thyroidectomy
- Maximizes therapeutic impact of RAI
- Easier mechanism of surveillance (no cells making thyroid hormone)
Cons of total thyroidectomy
- Increased risk of nerve injury
- Increased risk of damge to parathyroid glands
NO DIFFERENCE IN OVERALL OR DISEASE-SPECIFIC SURVIVAL
What are indications to go back for completion thyroidectomy after lobectomy for PTC?
Any of the following are indications for completion thyroidectomy:
- Tumor >4 cm
- Positive margins
- Extrathyroidal extension
- Macroscopic, multifocal disease (>1 cm)
- Contralateral disease
- Nodal metastasis
- Vascular invasion
- Poorly differentiated
FTC Surgical Treatment
Total thyroidectomy +/- therapeutic neck dissection for involved compartments for:
- Invasive cancer
- Metastatic disease
- Patient preference
OR
Lobectomy/isthmusectomy.
- If final path shows invasive cancer, proceed with completion thyroidectomy.
SAFE ANSWER: TOTAL THYROIDECTOMY +/- therapeutic LN dissection for known disease
Hurthle cell surgical treatment
Total thyroidectomy +/- therapeutic neck dissection for involved compartments for:
- Invasive cancer
- Metastatic disease
- Patient preference
OR
Lobectomy/isthmusectomy.
- If final path shows invasive cancer, proceed with completion thyroidectomy.
SAFE ANSWER: TOTAL THYROIDECTOMY +/- therapeutic LN dissection for known disease
Which thyroid carcinomas should RAI be considered in?
Cancers that are derived from follicular cells (since they uptake iodine)
- DTC (papillary, follicular, Hurthle cell)
In DTC, what are indications to consider RAI?
Consider RAI for:
- Tumors >2 cm
- Lymphovascular invasion
- LN metastasis
- Positive marins
- Gross extrathyroidal extension
- Postop unstimulated Tg >5-10
- Known or sustpected mets at presentation
RAI treatment plan
- 6-12 weeks post thyroidectomy
- With draw all thyroid hormone tx
- Pre-RAI imaging (whole body imaging with TSH stimulation)
- Treatment with oral Sodium Iodide I-131
- Post-RAI imaging
What additional postop treatment for papillary, follicular, or Hürthle carcinoma can be used (in addition to RAI)?
Levothyroxine to induce TSH suppresion.
DTC Follow-up (PTC, FTC, Hurthle)
q6month x2, then q1year
- H&P
- TSH
- Tg
- Anti-Tg antibodies
MTC Specific Workup
- CEA, Calcitonin, Ca
- Pheo screening (plasma free or 24-hour urine metanephrines)
-
RET proto-oncogene genetic testing
- If positive, obtain PTH & metanephrines
- Consider CT/MRI w/ contrast chest and liver
MTC Treatment
- < 1.0 cm and unilateral
- Total thyroidectomy
- Consider central LN dissection (VI)
- >/= 1.0 cm or bilateral
- Total thyroidectomy w/ central neck dissection
- Therapeutic neck dissection for identifiable disease
SAFE ANSWER EVERYTIME: TOTAL THYROIDECTOMY AND CENTAL NECK DISSECTION +/- additional neck dissection for known disease
*No role for RAI post-op as MTC is from parafollicular cells that do not take up I.
MTC Follow-up
2-3 months postop obtain CEA and calcitonin. If undetectable, enter active surveillance.
- Annual CEA, calcitonin
- For MEN2A or MEN2B, annual biochemical screening for HPT (PTH) or Pheo (metanephrines)
Timing of thyroidectomy in MEN2(A or B)
MEN2A/FMTC - Thyroidectomy by age 5 or when mutation identified if older.
MEN2B - Thyroidectomy during first year of life or at diagnosis.
Anaplastic Specific Workup
- CT Head/Neck/C/A/P w/ contrast
- Laryngoscopy
- PET scan (skull to thigh)
- +/- bronchoscopy
Anaplastic Surgical Treatment
If resectable:
- Total thyroidectomy with therapeutic lymph node dissection
In anaplastic carcinoma, what are treatment options for unresectable disease or incomplete resection?
- External Beam RT (EBRT)/Intensity-modulated RT (IMRT)
- Chemo
- Palliative care (median survival –> 6 months)
Key steps of Total Thyroidectomy
Neck Lymph Node Levels
Steps of LN Dissection
During thyroid/parathyroid surgery, what are two nerves that can be injured and their respective deficits?
- RLN (Recurrent laryngeal nerve)
- unilateral paralysis of ipsilateral cord
- affects speaking and swallowing
- bilateral injury can result in airway emergency given medialization of cords
- unilateral paralysis of ipsilateral cord
- EBSLN (External branch of the superior laryngeal nerve)
- innervated cricopharyngeous muscle
- inability to control high pressure phonation (high-pitched singing or yelling)
What do you do if you are concerned that all parathyroid glands have been compromised?
Mince and reimplant in SCM
