Chapter 25: Thyroid Cancer

Question 1

The thyroid produces these 2 hormones

Answer 1

1. Thyroid hormone
2. Calcitonin

Question 2

What are 3 things that thyroid hormone helps regulate?

Answer 2

1. Weight
2. Heart rate
3. Body temperature

Question 3

What does calcitonin do?

Answer 3

Maintain normal calcium levels

Question 4

What is the lifetime risk for thyroid cancer? And survival rate?

Answer 4

1.2% (98.3%)

Increased technology for earlier diagnosis has contributed to increased incidence

Question 5

What are 5 risk factors for thyroid cancer?

Answer 5

1. Exposure to radiation (especially earlier in infancy/childhood) - best established factor
2. Genetics (20-25% cases)
3. Female age 25-65
4. Family/personal hx of benign thyroid conditions (i.e. goitor)
5. Obesity in FEMALES - no correlation established with males

Question 6

Most widely known dietary risk factor for thyroid cancer

Answer 6

Iodine intake (both chronically deficient and high intake i.e. with supplements)

Follicular (deficient)
Papillary (excess)

F = fail, deFicient

Question 7

Link between fish intake and thyroid cancer?

Answer 7

Inconsistent, no established association

May be protective in areas where the soil, ground water, drinking water are low in iodine

Question 8

__________ contain goitrogens

Answer 8

Cruciferous vegetables

Question 9

What are goitrogens?

Answer 9

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

Question 10

Early thyroid cancer is often asymptomatic, but as cancer grows symptoms such as ________ can develop

Answer 10

1. Difficulty swallowing
2. Enlarged neck
3. Neck pain
4. Difficulty breathing
5. Coguh

Question 11

These are the 2 main types of thyroid cells

Answer 11

1. Follicular
2. Parafollicular

Question 12

Thyroid cancers are staged from 1-4, but ______ thyroid cancer is always considered stage 4

Thyroid cancer is also considered “differentiated” or
undifferentiated”

Answer 12

Anaplastic

Question 13

_________ cells are AKA “C” cells

Answer 13

Parafollicular
“C” cells produce calcitonin

Question 14

Role of thyroid/parathyroid hormones

Answer 14

1. Calcitonin - lowers blood calcium
2. Parathyroid hormone - increased blood calcium
3. Thyroid hormone - regulates heart rate, body temperature, weight

Question 15

Function of follicular cells

Answer 15

Produce and store thyroid hormone

Question 15

The ___________ is 4 small glands located on the back of the thyroid

Answer 15

Parathyroid

Question 16

Function of parafollicular cells

Answer 16

Produce calcitonin

Question 17

What are the 4 main types of thyroid cancer?

Answer 17

1. Anaplastic thyroid carcinoma
2. Follicular thyroid carcinoma
3. Medullary thyroid carcinoma
4. Papillary thyroid carcinoma

Question 18

Discuss anaplastic thyroid cancer

Answer 18

Always stage 4. Most undifferentiated. Very aggressive and typically fatal. Originates in follicular cells

Question 19

Discuss medullary thyroid cancer

Answer 19

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

Question 20

Rank thyroid cancers from most aggressive to least aggressive

Answer 20

1. Anaplastic
2. Medullary
3. Follicular
4. Papillary

(Avoid My..)

Question 21

Describe follicular thyroid cancer

Answer 21

Differentiated, originates in follicular cells. More aggressive and more likely to recur than papillary.

Question 22

Describe papillary thyroid cancer

Answer 22

Differentiated. Most common, slow growing. Best prognosis.

Question 23

Thyroid surgery can damage the __________ nerve, which may compromise ________ function

Answer 23

Laryngeal
Swallowing

*may also be d/t the compression of the thyroid glad

Question 24

Surgery is typically the treatment of choice but not in _________ thyroid cancer

Answer 24

Anaplastic, rarely indicated d/t advanced disease

Question 25

Where is thyroid stimulating hormone (TSH) produced?

Answer 25

Pituitary gland

Question 26

When may chemotherapy be used for thyroid cancer?

Answer 26

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

Question 27

Post total thyroidectomy, thyroid hormone replacement is usually provided while __________ suppressors may be given

Answer 27

Thyroid stimulating hormone

Question 28

What is the type of radioactive substance called used for thyroid cancer?

Answer 28

Iodine 131

Question 29

Is radioactive iodine (RAI) done pre or post-op

Answer 29

Post-op in high risk cases

Question 30

T/F: Only thyroid cells take up radioactive iodine, thus no other tissues are formed

Answer 30

True *a non-destructive form can be used for detection

Question 31

When is radiation (radiotherapy used) with thyroid cancer?

Answer 31

When surgery and RAI are ineffective

Question 32

Goal of low iodine therapy

Answer 32

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)

Question 33

Recommended Iodine restriction _________ /day Recommended duration for low iodine diet prior to RAI

Question 33

Is sea salt restricted on a low iodine diet?

Answer 33

No, this is a common misconception. Only contains trace levels of iodine

Question 34

On low iodine diet, avoid creams or lotions made from ______

Answer 34

seaweed

Question 35

Name 7 items to avoid with low iodine diet

Answer 35

1. Iodized salt 2. ALL seafood/sea products 3. Dairy products 4. Egg yolks 5. Erythrosine (red dye) 6. Iodate dough conditioners 7. Chocolate (bc of the milk)

Question 36

What to do about EN/PN patients requiring low iodine diet?

Answer 36

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