H_Review_Differentiated thyroid Cancer Flashcards
5 yr survival for papillary
97%
Differential dx of a thyroid nodule
Benign nodules ~90%
- Colloid nodules
- Folicular adenomas
- Cysts
Carcinoma
- Papillary 79%
- Follicular 13%
- Medullary 2%
- Lymphomas 2%
- Anaplastics 2%
Developmental
- Agenesis
- Thyroglossal cyst
Thyroiditis
Papillary Thyroid Cancer
- 70-80% most common
- Transformatio of follicular thyroid cells
- Histology:
- psammoma bodies-calcified remnants of infarcted papilea / follicles and colloid absent
- usually solitary thyroid nodule
- mets mostly VIA lymphatics / grows slowly / secretes Tg
Follicular thyroid cancers
- Thyroid follicular Cell transformation
- Impossible to distinguish from follicular adenomas by FNA
- will need capsular or lyphovascular invasion for it to be called follicular cancer
- RAS mutations make Tg
-
Histoloty:
- Microfollicular architecture, cuboidal cells
- Solitary thyroid nodules
- Iodine deficient areas
- Mets hematogenously not local
- High risk patients given I 131 adjuvant Rx
Anaplastic
Undifferentiated follicular Tumors
Mortalitiy about 100%
Medullary thyroid cancer 3%
C-Cells Calcitonin screening and levels
MEN2 Syndrome RET GENE
Mets
Breast, Lung, Renal, Melanoma
Factors of predictive of higher risk Papillary Ca
- Age > 45
- Male Sex
- Larger Tumors (> 4 cm)
- Extension outside the thyroid
- Lymph node involvements
- Invation into blood
- Tumor subtimes (Tall cell, insular)
AJCC TNM 2002 Staging of WDTC
Stage 1
- AGE < 45
- Any T, Any N, M0
- AGE > 45
- T1 (<2cm), N0, M0
AJCC TNM 2002 Staging of WDTC
Stage II
- AGE < 45
- M1
- AGE > 45
- T2 (2-4 cm), N0,M0
AJCC TNM 2002 Staging of WDTC
Stage III
- AGE > 45
- T3, and or N1a
AJCC TNM 2002 Staging of WDTC
Stage IV
T1 < 2
T2 - >2 cm and < 4 cm
T3 > 4 cm
- AGE > 45
- T4 or N1b or M1
ATA guidlines - TSH suppression in Thyroid cancer
Persistent dz
Free of dz but high risk
Low risk
Persistent disease TSH < 0.1 indefinitely
Free of dz but high risk TSH 0.1-0.5 5-10 yrs
Low risk TSH of 0.3-2.0
Radioactive iodine for remnant ablation
- Tg goal of 1-2 ng/ml for stimulated Tg
- Some retrospective studies show a reduction in recurrence rates but increases secondary cancers
- Increasing evidience suggests no benefit for low risk T1 / T2 / T3 lesions
Prepration for I 131
- Withdrawal of synthroid 2-4 weeks (TSH > 25
- or rhTSH, 2 IM injections cost 2-8K
- Low iodine for 1 week
- Pregnancy test
- stop breast feeding for 6-8 weeks before I 131
- Post treatment whole body scan must be performed
RAI side effects
- Salivary gland Injury
- N/V in children
- Avoid preg 6-12 months
- Transient decrease in sperm count
- Lacrimal duct injury
- Secondary Malignancies
Monitoring
US - 6-12 months post surgery
- If elevated Tg then US
- Abnormal Lymph node aspirated
- Metastatic Lymph nodes best treated by surgery
Thyroglobulin
- Same lab Annually
- TSH stimulated
- ~20% have tg ab interfering with assay
Tg detectable w/low TSH (> 1.0ng/ml) on LT4 what is next?
Neck US
Surgery if neck lesion
CT/MRI chest
I123 diagnostic scan with rhTSH
Treat w I131 if uptake present
Tg undetectable on LT4
Tg follow +/- US
if TgAb + then must US
Dx accuracy for detecting local recurrence
**US **
- SN 70% / SP 97.5%
- PPV 77.7% / NPV 92.4%
rhTSH TBscan (WBS not sensative)
- SN 20 % / SP 100%
- PPV 100 % / NPV 91%
rhTSH - Tg (TSH stimulated Tg)
- SN 78.2 % / SP 100 %
- PPV 100 % / NPV 98.2 %
Non radioiodine avid unresectable Dz
XRT in neck / bone / CNS
Preogressive mets can try TKI chemo
Slowly progressive dz can observe
