Histologic variants of thyroid cancer
1) Differentiated (papillary, follicular, Hurthle cell)
2) Medullary
3) Anaplastic
effect of gender as RF for thyroid cancer
Women are effected 3x men
How thyroid cancer is usually found
- nodules
- incidentally on imaging
Next step after FNA suspicious for malignancy
surgery
Surgical treatment modalities for thyroid cancer
Total thyroidectomy OR lobectomy depending on tumor size, nodal involvement
prognosis of anaplastic thyroid cancer
dismal
Thyroid cancers that are not RAI-avid
Medullary and anaplastic
Management following thyroidectomy for patients with high risk disease
RAI ablation routinely recommended
Preparation for RAI treatment
- Stop thyroid supplementation until TSH >30
- Low iodine diet for 1-2 weeks before treatment + no contrast CTs + no iodine-containing drugs
Follow-up after total thyroidectomy and RAI remnant ablation
Perform RAI scan 1 week after remnant ablation to detect metastatic disease
Long term follow-up of patients with differentiated thyroid cancer after total thyroidectomy and RAI remnant ablation
- Measure Tg q6-12 months for first 5 years
- ATGAB titer every 6-12 months for first 5 years
- IF high or intermediate risk, RAI scan 6012 months after
- Cervical neck US 6-12 months post surgery
Why is ATGAB measured?
- seen in 25% of patients with thyroid cancer and falsely lowers Tg level
- Persistence of ATGAB over 1 year or rise after thyroidectomy and RAI ablation may indicate recurrence
How else can you decrease mortality in differentiated thyroid cancer?
TSH suppression – TSH suppression to >0.1 is recommended for patients with high-risk differentiated thyroid cancer
Risks of TSH suppression therapy
1) Increased risk of AF
2) Increased risk of osteoporosis in postmenopausal women and older men
3) Symptomatic exacerbation of CAD
What thyroid cancers should not be managed with TSH suppression?
Medullary and anaplastic cancers – these are managed with thyroid supplementation to maintain euthyroid state after thyroidectomy
Significance of Tg rise after ablation
Concerning for relapse
Most common site of local recurrence in patients with thyroid cancer
Cervical lymph nodes
Most common sites of distant mets in patients with differentiated thyroid cancer
Lungs and bones, rarely brain
Most common sites of distant mets in patients with medullary thyroid cancer
Lungs, liver, and bones
Management of locoregional metastases in differentiated thyroid cancer
Surgical, adjuvant RAI
Management of pulmonary mets in differentiated thyroid cancer
IF RAI-avid –> RAI
Side effect to consider with RAI treatment
May cause acute swelling in metastatic areas, causing mass effect/compression of nearby structures – manage with steroids
efficacy of chemotherapy for metastatic differentiated thyroid cancer
Usually ineffective
Treatment of brain lesions
IF RAI avid –> steroids and EBRT, followed by RAI
Management of metastatic medullary thyroid cancer
- IF resectable lesions –> surgery +/o adjuvant EBERT
- Palliative EBRT to symptomatic distant lesions
SE’s of sorafenib
HTN + hand/foot syndrome
FDA-approved drugs for treatment of differentiated thyroid cancer
Sorafenib + lenvatinib
What is EBRT?
external beam radiation therapy
typical diagnosis of thyroid cancer
Ultrasound guided FNA
Management of anaplastic thyroid cancer
EBRT with radiosensitizing doxorubicin (Excision is often impossible due to invasion of local structures, but may be considered after neoadjuvant radiation)
Treatment of choice for localized medullary thyroid cancer
Total thyroidectomy with central neck dissection
Syndromes associated with increased risk of thyroid cancer
MEN2A and MEN2B
Cowden syndrome
Familial adenomatous polyposis
Treatment of choice for metastatic medullary thyroid cancer
Cabozantinib
Molecular target in medullary thyroid cancer
RET
FDA approved drugs for medullary thyroid cancer
Vandetanib, cabozantinib,
RET inhibitors —selpercatinib
Vandetanib SE to know about
QT prolongation
Cabozantinib AE to know about
fistula formation, GI tract perforation
goal of treatment in anaplastic
palliative in most cases
Targeted therapies approved for anaplastic
Dabrafenib + trametinib approved for BRAFV600E mutated anaplastic thyroid cancer
Differentiated thyroid cancer includes
Papillary, follicular, or hurthle cell
To remember with staging work up orders
NEVER use contrast because it can block radioactive iodine uptake
Chest imaging modality for staging of advanced thyroid cancer
CXR not CT (90% of disease will be local)
Treatment modalities for differentiated thyroid cancer
- total thyroidectomy
- RAI ablation
- TSH suppression with thyroid hormone
how to monitor patients post therapy in differentiated thyroid cancer
serial thyroglobulin levels
What does RAI refractory mean
Lesions that are progressing and which don’t take up RAI
RAI refractory on imaging
RAI uptake scan is negative but CT is positive
Targeted therapy approved for TRK/fusion cancers in differentiated thyroid cancer
Larotrectinib
Next step following diagnosis of medullary thyroid cancer
Germline RET gene mutation testing
Marker of recurrent or persistent cancer following thyroidectomy in differentiated thyroid cancers
thyroglobulin (secreted by most differentiated thyroid cancers (papillary and follicular))
Most common thyroid cancer type
papillary
Management of patient with differentiated thyroid cancer in surveillance with elevated thyroglobulin
US + radioiodine scan
surveillance of papillary thyroid cancer during year 1
- tsh, T4, thyroglobulin at 6 months
- neck US 6-12 months after initial therapy