Anaplastic Thyroid Cancer Flashcards
(16 cards)
Anaplastic Thyroid Cancer
- undifferentiated tumor of follicular cell origin.
- 1% of all thyroid cancers
- mean age at diagnosis is 65 years
- 2:1 female-to-male
- history multinodular goiter and previous thyroidectomy exists in up to 50% of patients.
- coexistence of PTC in at least 30% of cases
- transformation from differentiated cancer to ATC over time
- dedifferentiation event in ATC may involve mutations in the p53, 16p, catenin, beta 1, and PIK3CA genes.
Present with
- rapidly enlarging neck mass.
- local cervical symptoms
- Over half of patients have cervical lymphadenopath
- 15% to 50% of patients have distant metastases
- most common sites of distant metastases include the lungs, bone, and brain
Diagnosis
- confirmed with FNA
- Cytologic features of ATC include
» mixed patterns of spindled, pleomorphic giant, and squamoid cells with mitotic figures
» atypical mitoses, and extensive necrosis. - ATCs typically do not secrete or stain for Tg
Workup
- neck ultrasound and cross-sectional imaging of the neck and mediastinum to assess the extent of locoregional disease.
- Unlike in DTCs or MTCs,
» PET scan is recommended for a metastatic survey
which stage considered ? and Tx
- all ATCs are considered stage IV disease,
- nearly 100% disease-specific mortality.
- Multimodal treatment with EBRT and systemic therapy is indicated for locally advanced and metastatic disease.
- All patients with ATC should have initial consultations with palliative and end-of-life care specialists
Systemic Therapies for Advanced Thyroid Cancers
- systemic multitargeted tyrosine kinase inhibitor drugs for the treatment of advanced thyroid cancer in the United States
- Lenvatinib and sorafenib are approved for the treatment of RAI-refractory DTC
- vandetanib and cabozantinib are approved for progressive and advanced MTC.
lenvatinib targets
» VEGF receptor 1 to 3
» fibroblast growth factor receptor 1 to 4
» platelet-derived growth factor receptor-α
» RET, and c-Kit signaling pathway
whereas vandetanib
» selectively targets RET, VEGF receptor, and epidermal growth factor
The ATA guidelines recommend the use of these kinase inhibitors
for advanced metastatic
rapidly progressive
symptomatic
and/or imminently threatening disease
that is not otherwise amenable to local control using other approaches
selective BRAF and MEK inhibitors
> > The selective BRAF and MEK inhibitors
dabrafenib and trametinib were FDA approved as combination therapy for BRAF V600E mutated advanced and unresectable ATC
> > One mechanism behind these drugs’ efficacy may be in their ability to redifferentiate thyroid cancer cells so that they may once again respond to RAI treatment.
only FDA-approved cytotoxic chemotherapy agent for thyroid cancer
> > Doxorubicin is the only FDA-approved cytotoxic chemotherapy agent for thyroid cancer in the United States.
> > It appears to have a modest benefit in ATC but has not shown consistent evidence of benefit in advanced DTC or MTC.
Transcutaneous laryngeal ultrasound for pre op vocal cord assesemnt
It is less reliable in older and male patients largely due to inability of the transducer to penetrate beyond thyroid cartilage calcification
RLN
> > The left RLN is typically situated deeper and more medially and runs in a straighter cephalocaudad direction along the tracheoesophageal groove
> > the right RLN takes a more superficial and oblique course and may pass either anterior or posterior to the inferior thyroid artery
Two commonly used rules of thumb are used for RLN identification
1) it is located within 1 cm anteromedial to the superior parathyroid, at the level where nerve crosses the inferior thyroid artery
2) its course through Berry ligament is also situated just underneath and medial to the tubercle of Zuckerkandl, the small posterior protuberance of the mid-thyroid lobe.
outpatient thyroidectomy is appropriate for patients who
1) live within driving distance to the hospital
2) have reliable transportation and adult support at home for at least 24 hours
3) do not have significant perioperative comorbidities or take anticoagulants
4) do not have Graves disease
temporary and permanent RLN injury during thyroidectomy are in the
> > 4% to 10%
and
0.5% to 2% ranges
respectively
rates in the pediatric population are estimated to be up to fourfold higher
Unilateral and Bilateral RLN injury
> > hoarse and breathy voice, vocal fatigue, dysphagia, and aspiration
> > bilateral RLN injury with resultant resting vocal cord position in the midline can lead to airway compromise and can potentially require temporary or permanent tracheostomy
Injury to the EBSLN
vocal fatigue, decreased ability to reach higher pitch, and decreased ability to project the voice
