Download Thyroid Cancer

Thyroid Cancer
What is The Thyrid Gland?
 The thyroid gland is a butterfly-shaped
endocrine gland that is normally located in the
lower front of the neck.
 The thyroid’s job is to make thyroid hormones,
which are secreted into the blood and then
carried to every tissue in the body.
 Thyroid hormone helps the body use energy,
stay warm and keep the brain, heart, muscles,
and other organs working as they should.
Incidence of thyroid cancer
Although thyroid cancer is considered
a rare neoplasm, it is the most
common endocrine malignancy and
epidemiological studies report a
progressive increase in the incidence
of thyroid carcinoma in the last
twenty years.
THYROID NODULE
Thyroid Nodule
What is a Thyroid nodule?
 The term thyroid nodule refers to an
abnormal growth of thyroid cells that forms a
lump within the thyroid gland.
 Although the vast majority of thyroid nodules
are benign (noncancerous),a small proportion
of thyroid nodules do contain thyroid cancer
What are the symptoms of a Thyroid nodule?
 Most thyroid nodules do not cause
symptoms.
 Often, thyroid nodules are discovered
incidentally during a routine physical
examination or on imaging tests like CT scans
or neck ultrasound done for completely
unrelated reasons.
What are The symptoms of a Thyroid nodule?
 Occasionally, patients themselves find
thyroid nodules by noticing a lump in their
neck while looking in a mirror, buttoning their
collar, or fastening a necklace.
 Abnormal thyroid function tests may
occasionally be the reason a thyroid nodule is
found. Thyroid nodules may produce excess
amounts of thyroid hormone causing
hyperthyroidism
What are The symptoms of a Thyroid nodule?
 However, most thyroid nodules, including
those that cancerous, are actually nonfunctioning, meaning tests like TSH are
normal.
 Rarely, patients with thyroid nodules may
complain of pain in the neck,jaw, or ear.
What are The symptoms of a Thyroid nodule?
 If a nodule is large enough to compress the
windpipe or esophagus, it may cause
difficulty with breathing, swallowing, or
cause a “tickle in the throat”.
 Even less commonly, hoarseness can be
caused if the nodule invades the nerve that
controls the vocal cords but this is usually
related to thyroid cancer.
What are The symptoms of a Thyroid nodule?
The important points:
 Thyroid nodules generally do not cause
symptoms.

Thyroid tests are most typically normal
even when cancer is present in a nodule.
WHAT ARE THE RISK FACTORS
FOR THYROID CANCER?
Definition
 A risk factor is anything that affects a
person’s chance of getting a disease such as
cancer.
 Different cancers have different risk factors.
 Some risk factors, like smoking, can be
changed. Others, like a person’s age or family
history, can’t be changed.
 But risk factors don’t tell us everything.
 Having a risk factor, or even several risk
factors, does not mean that you will get the
disease. And many people who get the
disease may have few or no known risk
factors.
 Even if a person with thyroid cancer has a risk
factor, it is very hard to know how much that
risk factor may have contributed to the
cancer.
 Scientists have found a few risk factors that
make a person more likely to develop thyroid
cancer.
Thyroid cancer risk factors
• Gender and age
• For unclear reasons thyroid cancers (like
almost all diseases of the thyroid) occur
about 3 times more often in women than in
men.
• Thyroid cancer can occur at any age, but the
risk peaks earlier for women (who are most
often in their 40s or 50s when diagnosed)
than for men (who are usually in their 60s or
70s).
Thyroid cancer risk factors
A diet low in iodine
• Follicular thyroid cancers are more common
in areas of the world where people’s diets are
low in iodine. In the United States, most
people get enough iodine in their diet
because it is added to table salt and other
foods.
• A diet low in iodine may also increase the risk
of papillary cancer if the person also is
exposed to radioactivity.
Thyroid cancer risk factors
Radiation
 Exposure to radiation is a proven risk factor for
thyroid cancer.
 Sources of such radiation include certain
medical treatments and radiation fallout from
power plant accidents or nuclear weapons.
Thyroid cancer risk factors
• Having had head or neck radiation treatments in
childhood is a risk factor for thyroid cancer.
• Risk depends on how much radiation is given and
the age of the child.
• In general, the risk increases with larger doses
and with younger age at treatment. Before the
1960s, children were sometimes treated with low
doses of radiation for things we wouldn’t use
radiation for now, like acne, fungus infections of
the scalp (ringworm), or enlarged tonsils or
adenoids.
Thyroid cancer risk factors
 Radiation therapy in childhood for some
cancers such as lymphoma, Wilms tumor,
and neuroblastoma also increases risk.
 Thyroid cancers that develop after radiation
therapy are not more serious than other
thyroid cancers.
Thyroid cancer risk factors
• Imaging tests such as x-rays and CT scans
also expose children to radiation, but at much
lower doses, so it’s not clear how much they
might raise the risk of thyroid cancer (or other
cancers).
• If there is an increased risk it is likely to be
small, but to be safe, children should not have
these tests unless they are absolutely
needed.
Thyroid cancer risk factors
• Several studies have pointed to an increased risk of
thyroid cancer in children because of radioactive
fallout from nuclear weapons or power plant
accidents.
• For instance, thyroid cancer was many times more
common than normal in children who lived near
Chernobyl, the site of a 1986 nuclear plant accident
that exposed millions of people to radioactivity.
Adults involved with the cleanup after the accident
and those who lived near the plant have also had
higher rates of thyroid cancer. Children who had more
iodine in their diet appeared to have a lower risk.
Thyroid cancer risk factors
• Some radioactive fallout occurred over
certain regions of the United States after
nuclear weapons were tested in western
states during the 1950s. This exposure was
much, much lower than that around
Chernobyl. A higher risk of thyroid cancer has
not been proven at these low exposure levels.
Thyroid cancer risk factors
 Being exposed to radiation when you are an
adult carries much less risk of thyroid cancer.
Thyroid cancer risk factors
Hereditary conditions and family history
 Several inherited conditions have been linked
to different types of thyroid cancer, as has
family history.
 Still, most people who develop thyroid
cancer do not have an inherited condition or a
family history of the disease.
Thyroid cancer risk factors
Medullary thyroid cancer
• About 1 out of 3 medullary thyroid carcinomas
(MTCs) result from inheriting an abnormal
gene.
 In these inherited forms of MTC, the cancers
often develop during childhood or early
adulthood and can spread early. MTC is most
aggressive in the MEN 2b syndrome.
 If MEN 2a, MEN 2b, or isolated FMTC runs in
your family, you may be at very high risk of
developing MTC. Ask your doctor about
having regular blood tests or ultrasound
exams to look for problems and the
possibility of genetic testing
• Can thyroid cancer be prevented?
• Most people with thyroid cancer have no
known risk factors, so it is not possible to
prevent most cases of this disease.
Thyroid cancer in Iran
 The cancer shows considerable ethnic and
geographic variation and the highest incidence
rates are reported in areas of high iodine intake.
 On the other hand, the prognosis of cancer is
worse in endemic goiter regions compared to
countries with adequate iodine supply.
 Some authors have suggested that this may be
partly due to higher rates of undifferentiated
thyroid cancers, but no consensus is existing on
the issue.
Thyroid cancer in Iran
 In Iran, thyroid cancer has been reported in 1
year to 80 years old patients.
 In TUMS study, mean age of Iranian patients
was 42.8±0.9 with male patients being
markedly older.
 Patients affected by the anaplastic type were
older at the time of diagnosis, a finding in
agreement with the worse prognosis of this
type of thyroid cancer.
Thyroid cancer in Iran
 Thyroid cancer is more common among
women.
 The female to male ratio of Iranian patients
in TUMS study was 1.8. This ratio was 1.3 in
anaplastic carcinomas due to the higher
proportion of males affected.
 This finding that has been reported in other
series, which may partly describes the worse
prognosis of cancer among men
Thyroid cancer in Iran
 Thyroid gland is extremely radiosensitive,
which has been ascribed to its superficial site,
its high degree of oxygenation and the high
rate of cell division.
 Currently, a multicenteric project is being
conducted to evaluate the effect of high
background radiations on thyroid nodularity
and thyroid function of women living in the
HLRA of Ramsar.
Thyroid cancer in Iran
 In formerly iodine deficient regions, where
iodine supplementation has been introduced,
increased proportion of papillary histology
has been accompanied with decreased
numbers of anaplastic types.
Thyroid cancer in Iran
 In the TUMS study, the most common clinical
presentation (initial manifestation) was a
central neck mass.
 28.6% of the tumors had metastasized, most
frequently to the cervical lymph nodes, by the
time the patient presented.
Thyroid cancer in Iran
 Iran was an endemic goiter area with clear
indications of iodine deficiency.
Thyroid cancer in Iran
 Against expectation for an iodine-deficient
area, where FTC (follicular thyroid
carcinoma)is more common, TUMS findings
did not reflect this and the distribution of
tumors in that study was closer to what seen
in iodine rich areas with papillary and
follicular types accounted for 79.7% and 8.8%
of cases, respectively
Thyroid cancer in Iran
 Papillary carcinomas have much better
prognosis than follicular types and even some
authors believe thatpatients with papillary
cancer may survive the same as general
population.
Thyroid cancer in Iran
 It seems that as long as endemic goiter is a
frequent feature in a population, patients are
not worried about goiterous growth until
serious symptoms occur. By that time, small
well- differentiated thyroid carcinomas have
been replaced by larger less-differentiated
types
Presenting Signs and Symptoms in 1177
Patients Diagnosed with Carcinoma of the Thyroid
in Iran.
Increased incidence of thyroid
cancer?
• physicians might be identifying small cancers
that would have been overlooked in earlier
decades and the almost stable death rate
supports this point of view.
• Small papillary cancer makes up almost all of
the increase in cases.
• The prognosis is good and 6% of patients die
from the cancer
How is a Thyroid nodule evaluated?
 Once the nodule is discovered, your doctor
will try to determine whether the rest of your
thyroid is healthy or whether the entire
thyroid gland has been affected by a more
general condition such as hyperthyroidism or
hypothyroidism.
How is a Thyroid nodule evaluated?
 Your physician will feel the thyroid to see
whether the entire gland is enlarged and
whether a single or multiple nodules are
present.
 The initial laboratory tests may include
measurement of thyroid hormone (thyroxine,
or T4) and thyroid-stimulating hormone
(TSH) in your blood to determine whether
your thyroid is functioning normally.
How is a Thyroid nodule evaluated?
 Since it’s usually not possible to determine
whether a thyroid nodule is cancerous by
physical examination and blood tests alone,
the evaluation of the thyroid nodules often
includes specialized tests such as thyroid
ultrasonography and fine needle biopsy.
Thyroid Sonography:
 Thyroid ultrasound is a key tool for thyroid
nodule evaluation. It uses high-frequency
sound waves to obtain a picture of the
thyroid. This very accurate test can easily
determine if a nodule is solid or fluid filled
(cystic), and it can determine the precise size
of the nodule.
Thyroid Sonography:
 Ultrasound can help identify suspicious
nodules since some ultrasound characteristics
of thyroid nodules are more frequent in
thyroid cancer than in noncancerous nodules.
 Thyroid ultrasound can identify nodules that
are too small to feel during a physical
examination.
Thyroid Sonography:
 Ultrasound can also be used to accurately
guide a needle directly into a nodule when
your doctor thinks a fine needle biopsy is
needed.
 Once the initial evaluation is completed,
thyroid ultrasound can be used to keep an
eye on thyroid nodules that do not require
surgery to determine if they are growing or
shrinking over time.
Thyroid Ultrasound
 Risk of malignancy of a nodule is increased if:
 Irregular margins
 Intranodular vascular pattern
 Calcification
 Hypoechogenicity
 Halo
Thyroid fine needle aspiration bi opsy ( FNA Or
FNAB)
 A fine needle biopsy of a thyroid nodule may
sound frightening, but the needle used is very
small and a local anesthetic may not even be
necessary. This simple procedure is often
done in the doctor’s office. Sometimes,
medications like blood thinners may need to
be stopped for a few days before to the
procedure.
The report of a thyroid fine needle biopsy :
 1. The nodule is benign (noncancerous).
 2. The nodule is malignant (cancerous) or
suspicious for malignancy .
 3. The nodule is indeterminate.
 4. The biopsy may also be nondiagnostic or
inadequate.
1-The nodule is benign (noncancerous).
 This result is
obtained in
up to
80% of biopsies.
 The risk of overlooking a cancer when the
biopsy is benign is generally less than 3 in 100
tests or 3%.
 This is even lower when the biopsy is
reviewed by an experienced pathologist at a
major medical center.
1-The nodule is benign (noncancerous).
 Generally, benign thyroid nodules do not
need to be removed unless they are causing
symptoms like choking or difficulty
swallowing.
 Follow up ultrasound exams are important.
 Occasionally, another biopsy may be required
in the future, especially if the nodule grows
over time
2-The nodule is malignant (cancerous) or
suspicious for malignancy
 A malignant result is obtained in about 5%
of biopsies and is most often due to papillary
cancer, which is the most common type of
thyroid cancer.
 A suspicious biopsy has a 50-75% risk of
cancer in the nodule.
 These diagnoses require surgical removal of
the thyroid after consultation with your
endocrinologist and surgeon.
3-The biopsy may also be nondiagnostic or
inadequate.
 This result is obtained in less than 5% of cases
when an ultrasound is used to guide the FNA.
This result indicates that not enough cells
were obtained to make a diagnosis but is a
common result if the nodule is a cyst.
 These nodules may require reevaluation with
second fine needle biopsy, or may need to be
removed surgically depending on the clinical
judgment of your doctor.
Prevalence of Thyroid Nodule:
 Prevalence depends on method of detection:
 Palpable nodules
 1-2% of men and 5-7% of women>age 40
 BY US:
 7.5 MHz US transducer
 27% of women; 15% of men
 10 MHz Us transducer
 72% of women; 41% of men
Suspicious for Malignancy
 History:
Recent rapid growth of nodule
Family history of thyroid cancer
Past irradiation to head and neck
 Physical examination:
Vocal cord paralysis
Fixation to adjacent tissue
Cervical lymphadenopathy
Hard, firm nodule
Approach to Thyroid Nodule
 1. First step- measure TSH
 2. If TSH is suppressed (↓) the thyroid gland is
hyper-functioning
 3. Look for autonomous nodule by thyroid scan
 5% of thyroid nodules are autonomous nodules.
these nodules aren’t cancer!
A Functional Thyroid Nodule
Normal thyroid scan
ONLY 20% OF COLD NODULES ARE MALIGNANT!
ATA Clinical Practice Guidelines for
Diagnosis and Management of Thyroid
Nodules
IF TSH is normal or elevated

Fine needle aspiration (FNA) is indicated
for nodules>10 mm.

If <10mm aspirate if clinical risk factors
or suspicious sonographically.
Symptoms of thyroid cancer
 This cancer may produce a wide range of
clinical presentations; from those that behave
like benign tumors,to highly invasive tumors.
Complication of thyroid cancer
These differences are attributed to factors such
as:
 Histological features.
 Tumor stage.
 Age at diagnosis (age more than 60 is defined
as poor prognostic factor).
 Gender (male gender signals a worse
outcome)
THYROID CANCER- Classification:
1. Papillary - good prognosis (10 yrs survival 98%)
2. Follicular - good prognosis (10 yrs survival 92%)
3- Medullary thyroid cancer (10 yrs survival 75%)
4- Thyroid lymphoma 10 yrs survival ( 50%)
5- Anaplastic - poor prognosis ((10 yrs survival 13%)
6-Metastases from breast, colon, renal,
melanoma
Thyroid nodule investigation- algorithm
Scan
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“hot”, “warm”
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TSH
Normal
High
Treat
hypothyroidism
“cold”
Normal
Surgery
131I
Low
FNAB
“Follicular lesion”
Rx
Scan
Follow-up
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“warm”
Inadequate
Rebiopsy
Malignant
Suspicious
Surgery
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“cold”
‫خسته نباشید‬