Download Chapter 124: Management of Thyroid Neoplasms

UCLA Head and Neck Surgery Didactics
September 18, 2013
Matthew K. Lee, MD
Gender
Female > Males
3 : 1 ratio for well differentiated
Age
Women: 45 – 50
Men: 65 – 70
Overall bimodal distribution of thyroid carcinoma
< 20 years and > 70 years
Diet
Endemic goiter (iodine deficiency) and follicular /
anaplastic carcinoma
Radiation
Low dose (< 20 Gy)
Adenotonsillar Hypertrophy
Acne
Hemangiomas
Scrofula
1/3 with radiation history have nodules
½ of these nodules harbor cancer
Family History
+FHx in 6% of patients
Associated with Gardner’s syndrome, Cowden’s syndrome,
and MEN syndromes
History
Increased level of suspicion in very old and very young
patients
Rapid growth in existing nodule is red flag
Malignant degeneration or hemorrhage
Exam
> 2 cm higher risk of harboring cancer
Palpate for goiter and substernal extension
Pemberton’s Manuever
Laboratory Studies
TFTs
Abnormal  think functional disorder
FNA
For PTC: False negative 1%, false positive 5%
15% nondiagnostic
Should not be taken as negative FNA
Cannot be used to determine follicular carcinoma
Histologic architecture
Hurthle Cells
Ultrasound
Suspicious findings
Microcalcifications
Hypoechogenicity of solid nodule
Nodes with loss of the fatty hilum
Increased vascularity
Rounded node configuration
CT and MRI
Superior for substernal extension, determining
adenopathy, and tracheal invasion
Wolf-Chaikoff Effect
A
M
E
S
Age < 41 in M, < 51 in F
Metastases
Extrathryoidal
Size < 5 cm
Low risk Category
Young, no distal mets
Older, but small tumor with no extrathyroidal disease
Mortality rate of 1.8%, recurrence 5%
High risk
Mortality rate of 46%, recurrence 55%
M
A
C
I
S
Metastasis
Age
Completeness of surgical resection
Invasion of extrathyroidal tissue
Size of tumor
MACIS is the updated version of AGES
classification
Most common subtype (80%)
High rates of nodal metastases
70 – 80% microscopically
15 – 30% clinically
Multifocal
Microcarcinoma (< 1 cm) incidentally found in contralateral lobe
in up to 80% of specimens
Treatment
Total Thyroidectomy
Central Neck Dissection only for clinically palpable nodes
Prognosis
5 year OS: 95%
Second most common (10%)
Unifocal
Hematogenous spread more common than
lymphatic spread
Treatment
Total thyroidectomy without central neck dissection
Prognosis
5 year OS: 70 – 85%
Hurthle cell variant 5 year OS: 50%
Derived from parafollicular C-cells (which produce calcitonin, hence
amyloid)
Sporadic (80%) and Familial (20%) Variants
Familial = multicentric, associated with MEN or RET mutation
High rate of Nodal Metastases
60 - 80% nodal involvement
Least iodine avid
Treatment
Total Thyroidectomy with Central Neck Dissection
If MEN II a/b syndrome, consider prophylactic thryoidectomy
Prognosis
5 year OS: 50-80%
Worse if
Likely arises from transformation of well
differentiated thyroid carcinoma
Universally fatal
Median survival < 6 months
Treatment
Palliative
Consider tracheotomy
Calcium Monitoring
Thyroid Hormone Replacement
Thyroid hormone replacement has two-fold purpose:
Prevent symptomatic hypothyroidism
Suppress TSH < 0.1 mU/L to prevent trophic effect of TSH on
thyroid tumors
Use Cytomel rather than Synthroid
T3, Liothyronine
Shorter half-life (2-3 days) to allow for RAI
Mechanism of Action
I-131 isotope emits B particles that penetrate and destroy
tissue within 2 mm zone
Patient must be in hypothyroid state in order to facilitate
iodine uptake
Purpose
Used for PTC and Follicular (as well as MTC and Hurthle cell
despite low iodine uptake)
Remnant ablation (for monitoring)
Adjunctive treatment of malignancy
Indications
Distant or nodal metastases
Gross extrathyroidal extension
Tumor size > 4 cm
Softer indications
High grade histology: tall cell, columnar, insular, and solid variants
Multifocal disease > 1 cm
Not indicated in:
Unifocal disease < 1 cm
Multifocal disease all < 1 cm
Dose
Typically 100 mCi (though lower doses of 30 have been
used)
Adverse effects
300: infertility
600: pulmonary fibrosis
900: leukemia/lymphoma, bladder cancer
Other side effects: sialadenitis, nausea, neck
tenderness, metallic taste
Low Risk Patients
Check thyroid hormone levels
Check q 1 year x 2 years, then q5 years for 20 years
TG should be < 2 ng/mL (if TT + RAI)
If TG elevated, perform radioiodine scan
High Risk Patients
Regular U/S and whole body radioiodine scans q6 to 12 months
MTC
Calcitonin (pentagastrin stimulated)
UCLA Head and Neck Surgery Didactics
September 18, 2013
Matthew K. Lee, MD
Regulated by the interaction of:
PTH
Vitamin D
Calcitonin
Regulated by the interaction of:
Vitamin D
Calcitonin
PTH is immediate regulator of calcium levels
Vitamin D works via GI system, and is therefore
slower
Explains why patients initiated on Rocaltrol do not
see immediate increase in calcium levels
Calcitonin
Least important regulator, inhibits bone resorption
Normal Dimensions
5 x 3 x 1 mm, 60 mg
Fat content not reliable marker of normal versus
hypercellular parathyroid
Varies by patient: Women and older patients have
higher fat content within parathyroid
90% of patients have 4 glands
10% can have fewer gland or supernumerary
Superior Parathryoids
80% will be near the CT junction 1 cm above the
intersectionof the RLN and ITA
Inferior parathyroids
More variable location
50% at inferior pole
30% within thyrothymic ligament or intrathymic
Vascular Supply
80% of have common supply to both superior and
inferior glands via the ITA
20% have superior gland supplied by the STA
Rich anastomoses exist
Parathyroid Adenoma
Single or double
Accounts for 90% of primary hyperparathyroidism
Multiple Gland Hyperplasia
Can be primary or secondary (renal failure)
Parathyroid Carcinoma
Stones
Nephrolithiasis
Occurs in 4%
Bones
Osteitis Fibrosa Cystica
Incidence 1%
Subperiosteal erosion, bone demineralization, Brown
tumors (accumulations of osteoclasts, blasts, and fibrous
matrix), pathologic fractures
Groans
PUD, pancreatitis, cholelithiasis, and constipation
Moans
Anxiety, depression, cognitive dysfunction
Elevated calcium level with elevated PTH
Need to rule out other causes
Poor Ca / Vitamin D intake
Can cause overall decrease in Ca, leading to compensatory
elevation of PTH bringing serum Ca back into the normal range
Familial Hypocalciuric Hypercalcemia
Mutation in the calcium sensing receptor
Leads to increased PTH and Ca levels
Can be distinguished based on 24 hour urine calcium to
creatinine clearance ratio (FHH is ratio < 0.01, have low
calcium excretion relative to their serum calcium)
Technetium / Thallium Imaging
“Subtraction” study
Technetium Sestamibi
Sestamibi with SPECT
CT – Sestamibi fusion
U/S
MRI / CT
Arteriography (angio)
Appears as a hypervascular mass
Selective venous sampling
Sample from IJ, innominate, and superior vena cava
Should be twice what is in peripheral blood
U/S guided FNA
Indications for Surgery
Serum Ca > 1 mg/dL above the upper limit
Cr Clearance reduced > 30% for age
24-hour urinary Ca > 400 mg/dL.
< 50 years old
Bone mineral density reduced by 1 STD
Patients request surgery, or patients are unsuitable for
long-term surveillance
Expose via similar approach as thyroidectomy
If localized, can perform selective excision of
adenoma
Successful outcome: > 50% drop in iPTH and into
normal range
Non-localized
4 gland exploration
If multigland hyperplasia, can perform 3 ½ gland
excision versus 4 gland excision with reimplantation
and cryopreservation of tissue
Focused Minimal Access Approach
2 cm incision at medial border of SCM, dissect
between straps and SCM
Endoscopic
Radioguided Surgery
Tc – Sestamibi administration 2 hours prior, use
handheld gamma probe