Endo: Thyroid Nodules And Cancer

Front 1

Thyroid nodule evaluation to cancer diagnosis (if applicable)

Back 1

Nodule found - thyroid labs drawn - thyroid imaging (US, nuclear medicine) - may biopsy - dx cancer - perform surgery, may need additional treatment

Front 2

Thyroid Cancer Types

Back 2

Papillary Carcinoma - well differentiated - 80%
Follicular Carcinoma - well differentiated - 10%
Medullary Carcinoma - 5%
Anaplastic Carcinoma - 2%

Papillary is pretty benign but most malignant cancer anywhere in body is anaplastic thyroid cancer

Front 3

Thyroid Nodules prevalence

Back 3

Majority of thyroid cancers present as nodules

5% of adults have palpable nodules and over half have nodules detectable by US, malignancy rate is 5%, rarely symptomatic

Front 4

Worrisome clinical characteristics of a nodule

Back 4

Prior head and neck irradiation
Family history of MEN2 or Medullary Thyroid Cancer
Age <20 or >70, Male (not factored in staging)
Growing
Firm/hard or fixed nodule
Cervical adenopathy
Dysphonia, dysphagia, cough

Front 5

Thyroid Ultrasound Indications, Use, When is it not indicated

Back 5

Use: Best initial evaluation, tells nodule types and lymphadenopathy, can help show things that may predict malignancy (microcalcifications, etc)

Indications: Any palpable nodule, incidentally discovered nodule (ie neck x-ray or CT)

Not Indicated: medical thyroid disease (hypo or hyperthyroidism) if gland does not have a palpable nodule; If hyperthryoid and hot nodule or have toxic multinodular goiter may do but not hypothyroidism. ONLY time can use as a screening test is high genetic risk or radiation exposure

Front 6

What is main thing gained from FNA and US

Back 6

FNA developed and reduced number of surgeries needed and increased surgical yield of cancer

Thyroid US can help select patients for biopsy to increase FNA yield

Front 7

Who needs FNA, ATA guidelines for who needs a biopsy

Back 7

Not based just on size of nodules (equal malignancy chance), MUST be larger than 5mm

Can be difficult to reach if have large neck or large goiter

DO NOT use size cutoff as standard b/c not reliable

ATA guidelines
a) Over 5mm
b) Suspicious US features OR high risk history
c) ANY with lymphadenopahty
d) NEVER purely cystic
Others based on size but NEVER just use size

Front 8

Workup of a Thyroid Nodule, Biopsy outcomes

Back 8

1) H&P, find out if any high risk factors (radiation, family history of thyroid cancer)

2) Check TSH (first test before any imaging).
a) If TSH is low then nodule islikely overactive and most likely benign. Iodine scan positive (hyperfunctioning) means likely just hyperthyroidism so treat for that

If it doesn't light up on iodine scan (non functional) want to workup with US for possibility of cancer

b) TSH is normal or high, workup for possibility of cancer

3) Suspicion of cancer (nonfunctional TSH low OR normal or high TSH) - Do US to see if there is an actual nodule

4) If nodule biopsy and there are 5 outcomes
a) Benign - may still monitor over time
b) Non-diagnostic - repeat and if still nondiagnostic follow or consider surgery
c) Malignancy - need to remove thyroid, look at lymph nodes around
d) Suspicious - will remove thyroid but might be benign, can monitor if older pt or comorbid conditions
e) Intermediate - Pathologist cannot determine, recommend taking out if younger b/c 1/3 of these are cancerous. I-123 scan if warm makes you think its probably OK and can just watch

Front 9

Epidemiology of Thyroid Cancer, incidence changes, why

Back 9

1% of all cancer deaths, INCREASING incidence

Because:
a) Imaging tech is driving "epidemic" of nodules being seen, majority are "incidentalomas" rather than palpable nodules

ALL of the increase is from papillary carcinoma (lowest cancer risk), but the other types haven't changed at all. Biggest rise in 0-1cm tiny nodules = ASYMPTOMATIC

Also mortality remained stable, so "increased diagnostic scrutiny" may be cause.

Front 10

Staging in thyroid cancer key parts

Back 10

Prognosis worse if older than 45, If under 45 highest stage is Stage II even if have metastasis

Stages raised by Tumor size, number of lymph nodes, and metastatic disease

Front 11

Disease Free Survival of Thyroid Cancers

Back 11

GOOD, 80% if Stage I are disease free 25 years, 97% have cancer specific survival (don't die of the disease)

As stage increases, it falls off

BUT even in older pts have over 80% survival so need to balance treatment to not cause new problems

Front 12

Risk Factors for Recurrence, Death

Back 12

Same

Tumor size, multiple tumors, metastasis, staging

Front 13

Use of Radioactive Iodine

Back 13

Mainstay of thyroid cancer treatment after surgery, major component of thyroid hormone

Kills remaining thyroid tissue, lower risk for recurrence and death

NOT conclusive though, may not decrease recurrence or mortality so may be reconsidered

Front 14

RAI current recommendations

Back 14

T1 - smaller, low stage tumors, iodine does not decrease risk of death or recurrence so don't give it

T2 - not clear, patient can guide, may have some benefit but there are side effects

T3 - Definitely recommend iodine

Front 15

Current Conclusions for Thyroid Nodules

Back 15

Stage I cancers are low risk, with very low rates of cause-specific mortality

Treat with total or near-total thyroidectomy
Remnant ablation has little effect on small tumors

Node positivity and distant metastasis increase risk for recurrence and mortality

RAI limited benefit in small tumors (T1)

Front 16

Problems with over diagnosing, Is there a benefit

Back 16

Needless surgeries
Requires lifelong thyroid hormone replacement
Requires lifelong followup

Benefit
Very sensitive screening test (US) for common indolent disease (1/3 cadavers has thyroid cancer but clinical disease is only 1% of all cancers and 0.5% of deaths)

Cannot just go off nodule size, imaging properties more important for which ones actually warrant further workup
Similar to prostate cancer

Front 17

Molecular marker suggesting aggressive disease

Back 17

BRAF mutations - part of protein kinase pathway leading extracellular signal regulated kinase (ERK) regulating cell survival, proliferation, differentiation

Also seen in melanomas, could be potential therapeutic target as well as diagnostic tool

BRAF mutation seen in 50% of thyroid cancers, more likely to be invasive and aggressive and recurrent. MAY BE helpful

Front 18

Treatment for Micropapillary Thyroid Cancer

Back 18

Surgery is Standard of care, BUT debate over total vs near-total thyroidectomy

Current is central compartment dissection but raises risk of hypoparathyroidism