Chapter 25: Thyroid Cancer Flashcards
The thyroid produces these 2 hormones
- Thyroid hormone
- Calcitonin
What are 3 things that thyroid hormone helps regulate?
- Weight
- Heart rate
- Body temperature
What does calcitonin do?
Maintain normal calcium levels
What is the lifetime risk for thyroid cancer? And survival rate?
1.2% (98.3%)
Increased technology for earlier diagnosis has contributed to increased incidence
What are 5 risk factors for thyroid cancer?
- Exposure to radiation (especially earlier in infancy/childhood) - best established factor
- Genetics (20-25% cases)
- Female age 25-65
- Family/personal hx of benign thyroid conditions (i.e. goitor)
- Obesity in FEMALES - no correlation established with males
Most widely known dietary risk factor for thyroid cancer
Iodine intake (both chronically deficient and high intake i.e. with supplements)
Follicular (deficient)
Papillary (excess)
F = fail, deFicient
Link between fish intake and thyroid cancer?
Inconsistent, no established association
May be protective in areas where the soil, ground water, drinking water are low in iodine
__________ contain goitrogens
Cruciferous vegetables
What are goitrogens?
Goiter-producing compounds. shown to induce thyroid cancer in animals but not humans
Likely that unfavorable benefits of goitrogens are outweighed by the protective benefits of other plant constituents
Early thyroid cancer is often asymptomatic, but as cancer grows symptoms such as ________ can develop
- Difficulty swallowing
- Enlarged neck
- Neck pain
- Difficulty breathing
- Coguh
These are the 2 main types of thyroid cells
- Follicular
- Parafollicular
Thyroid cancers are staged from 1-4, but ______ thyroid cancer is always considered stage 4
Thyroid cancer is also considered “differentiated” or
undifferentiated”
Anaplastic
_________ cells are AKA “C” cells
Parafollicular
“C” cells produce calcitonin
Role of thyroid/parathyroid hormones
- Calcitonin - lowers blood calcium
- Parathyroid hormone - increased blood calcium
- Thyroid hormone - regulates heart rate, body temperature, weight
Function of follicular cells
Produce and store thyroid hormone
The ___________ is 4 small glands located on the back of the thyroid
Parathyroid
Function of parafollicular cells
Produce calcitonin
What are the 4 main types of thyroid cancer?
- Anaplastic thyroid carcinoma
- Follicular thyroid carcinoma
- Medullary thyroid carcinoma
- Papillary thyroid carcinoma
Discuss anaplastic thyroid cancer
Always stage 4. Most undifferentiated. Very aggressive and typically fatal. Originates in follicular cells
Discuss medullary thyroid cancer
Less differentiated and somewhat aggressive. Originates in the C cells. More likely to spread. Releases high levels of calcitonin & CEA
*only that arises in C cells
Rank thyroid cancers from most aggressive to least aggressive
- Anaplastic
- Medullary
- Follicular
- Papillary
(Avoid My..)
Describe follicular thyroid cancer
Differentiated, originates in follicular cells. More aggressive and more likely to recur than papillary.
Describe papillary thyroid cancer
Differentiated. Most common, slow growing. Best prognosis.
Thyroid surgery can damage the __________ nerve, which may compromise ________ function
Laryngeal
Swallowing
*may also be d/t the compression of the thyroid glad
Surgery is typically the treatment of choice but not in _________ thyroid cancer
Anaplastic, rarely indicated d/t advanced disease
Where is thyroid stimulating hormone (TSH) produced?
Pituitary gland
When may chemotherapy be used for thyroid cancer?
Metastatic disease, almost as a last option
If radioactive iodine therapy, radiation, and TSH-suppressive therapy don’t work
Typically rare in anaplastic thyroid cancer though d/t the aggressive nature
Post total thyroidectomy, thyroid hormone replacement is usually provided while __________ suppressors may be given
Thyroid stimulating hormone
What is the type of radioactive substance called used for thyroid cancer?
Iodine 131
Is radioactive iodine (RAI) done pre or post-op
Post-op in high risk cases
T/F: Only thyroid cells take up radioactive iodine, thus no other tissues are formed
True
*a non-destructive form can be used for detection
When is radiation (radiotherapy used) with thyroid cancer?
When surgery and RAI are ineffective
Goal of low iodine therapy
To deplete whole-body iodine stores before scans or therapy to optimize RAI uptake in thyroid cells
*urinary iodine can be used to assess iodine status (low in urine, low in diet)
Recommended Iodine restriction _________ /day
Recommended duration for low iodine diet prior to RAI
</= 50 mcg/day
1-2 weeks
Is sea salt restricted on a low iodine diet?
No, this is a common misconception. Only contains trace levels of iodine
On low iodine diet, avoid creams or lotions made from ______
seaweed
Name 7 items to avoid with low iodine diet
- Iodized salt
- ALL seafood/sea products
- Dairy products
- Egg yolks
- Erythrosine (red dye)
- Iodate dough conditioners
- Chocolate (bc of the milk)
What to do about EN/PN patients requiring low iodine diet?
PN - all good, trace element products typically don’t contain iodine
EN - no formulas suitable, must puree food products acceptable on a low iodine diet
