Chapter 25: MNT for Thyroid Cancer Flashcards
Thyroid produces thyroid hormones wich help regulate:
Heart rate
Body temperature
Weight
Calcitonin (hormone that helps maintain normal calcium levels)
Thyroid cancers develop in _____ and _____ cells.
Follicular and parafollicular
Risk Factors for Thyroid Cancer (TC)
Exposure to radiation (especially during infancy or childhood)
Genetic mutations (genetic factors are responsible for 20-25% of medullary carcinomas)
Female gender
Age >25 and 65
Family history
Personal hx of benign thyroid conditions such as goiter
Obesity
Symptoms of TC
Typically asymptomatic in early TC.
Cough, difficulty swallowing or breathing, enlargement of or lump on the thyroid gland, neck pain, and hoarseness or change in voice can occur.
How is TC diagnosed?
Blood tests: TSH or calcitonin
Thyroid ultrasound
Radioactive scans
Biopsy
Dietary Risk Factors - Iodine
Chronic iodine insufficiency is a/w increased risk of follicular carcinoma
High iodine intake is a/w increased risk of papillary carcinoma
Dietary Risk Factors - Cruciferous Vegetables
Contain goitrogens (goiter producing compound) that can induce thyroid cancer in animals. Not supported in human studies.
Dietary Risk Factors - MISC
Potential associated with soy intake, green tea, alcohol consumption, nitrate and nitrite consumption
Staging of TC
Based on primary tumor assessment, regional lymph nodes, distant mets. Stages I - IV.
Types of Thyroid Cancer
Anaplastic TC - most undifferentiated, always considered stage IV, very aggressive and usually fatal, least common type of TC
Follicular TC - differentiated, generally good outcomes, more aggressive than papillary and can spread to other organs, more likely to recur than papillatry
Medullary TC - somewhat aggressive, less differentiated, originates in C-cells, more likely to spread to LN and other organs, releases high levels of calcitonin and carcinoembryonic antigen
Papillary TC - most common, 80% of TC, best prognosis
Treatment - Surgery
Therapy of choice
Total or near-total thyroidectomy is indicated often
Lobectomy can be performed in some cases
If pt has LN mets, removal of LN and neck dissection are recommended
Post-op thyroid hormone replacement is necessary
Risk of TC Surgery
Surgery can damage recurrent laryngeal nerve which can affect swallowing function
Chemotherapy
Lenvatinib works well but is toxic (67% of pts respond well). We don’t use Sorafenib as much as we used to as it has a lower response rate (11%).
BRAF mutation? Standard treatment is Dabrafenibi and Trametinib based on phase II study.
Cabozantinib was recently approved for use as well.
Targeted therapies don’t work quite as well.
Radiotherapty and Radioactive Iodine Therapy (RAI)
May be indicated post-op to treat persistent disease in differentiated TC. RAI is concentrated by TC cells and leads to apoptosis; since only thyroid cancer cells can take up RAI, no other tissues are harmed.
NIS of RAI
Nausea, dry mouth, change in taste, late onset damage of salvary glands and dental caries.
