THYROID CANCER
Thyroid Cancer Type and
Incidence
Papillary ~ 60-75%
Follicular ~20-30%
Medullary ~ 5-10%
Anaplastic ~ 3%
KEY POINTS
Thyroid cancer is the most common
malignancy of the endocrine glands.
The great majority of cancers of the
follicular thyroid epithelium are well-
differentiated (papillary and
follicular) and have a good
prognosis, particularly in young
patients.
KEY POINTS
Thyroid Ca is one of the most
curable cancers.
The incidence of thyroid Ca in
thyroid nodules ranges from
0.5% to 10%.
ETIOPATHOGENESIS
ONCOGENES:
– gene rearrangements RET/PTC
(papillary Ca)
– mutations of the ras gene family
(an early event in thyroid
tumorigenesis)
– inactivating mutations of the p53
tumor-suppressor gene
(undiffereniated thyroid Ca)
ETIOPATHOGENESIS
External irradiation of the neck
(the latency period is at least 5
years)
Iodine deficiency (Follicular Ca)
PAPILLARY CANCER
The Most Common Thyroid
Cancer
Peak onset ages 30 through 50
Females more common than males by 3
to 1 ratio
Prognosis directly related to tumor size
[less than 1.0 cm - good prognosis]
Accounts for 85% of thyroid cancers
due to radiation exposure
PAPILLARY CANCER
Spread to lymph nodes of the neck
present in more than 50% of cases
Distant spread (to lungs or bones)
is very uncommon
Overall cure rate very high
(near 100% for small lesions in
young patients)
MANAGEMENT OF
PAPILLARY THYROID
CANCER
Papillary carcinomas that are
well circumscribed, isolated, and
less than 1cm in a young patient
(20-40) without a history of
radiation exposure may be
treated with hemithyroidectomy
and isthmusthectomy.
MANAGEMENT OF
PAPILLARY THYROID
CANCER
All others should be treated
with total thyroidectomy and
removal of any enlarged
lymph nodes in the central or
lateral neck areas.
MANAGEMENT OF
PAPILLARY THYROID
CANCER AFTER SURGERY
Since papillary cancer may
respond to TSH, thyroid
hormone is given in doses
large enough to suppress
secretion of TSH and help
prevent a recurrence.
MANAGEMENT OF
PAPILLARY THYROID
CANCER AFTER SURGERY
Serum FT3 i FT4 should be in the
normal range to avoid iatrogenic
thyrotoxicosis
Serum Tg, a marker of cell
function, increases dramatically
during hypothyroidism, while it
returns to low levels during
hormone therapy
MANAGEMENT OF
PAPILLARY THYROID
CANCER AFTER SURGERY
Papillary cancer cells absorb
iodine and therefore they
can be targeted for death
by giving the toxic isotope
(I-131).
MANAGEMENT OF
PAPILLARY THYROID
CANCER AFTER SURGERY
In patients with larger tumors,
spread to lymph nodes or other
areas, tumors which appear
aggressive microscopically,
radioactive iodine is often given in
expectation that any remaining
thyroid tissue or cancer that has
spread away from the thyroid will
take it up and be destroyed.
PAPILLARY THYROID
CANCER LONG-TERM
FOLLOW UP
A yearly chest X-ray
A yearly chest X-ray
Thyroglobulin levels
a high serum thyroglobulin level that
had previously been low following total
thyroidectomy especially if gradually
increased with TSH stimulation is
virtually indicative of recurrence.
A value of greater than 10 ng/ml is often
associated with recurrence even if an
iodine scan is negative.
FOLLICULAR CANCER
THE SECOND MOST COMMON THYROID
CANCER
Peak onset ages 40 through 60
Females more common than males by 3
to 1 ratio
Prognosis directly related to tumor size
[less than 1.0 cm - good prognosis]
Rarely associated with radiation
exposure
Spread to lymph nodes is uncommon
(~10%)
FOLLICULAR CANCER
Invasion into vascular structures
(veins and arteries) within the
thyroid gland is common.
Distant spread (to lungs or bones) is
uncommon, but more common than
with papillary cancer.
Overall cure rate high (near 95% for
small lesions in young patients),
decreases with advanced age.
FOLLICULAR THYROID
CANCER
Many cases of follicular thyroid cancer
are subclinical.
Most common presentation of thyroid
cancer is an asymptomatic thyroid mass,
or a nodule, that can be felt in the neck.
Some patients have persistent cough,
difficulty breathing, or difficulty
swallowing.
Pain seldom is an early warning sign of
thyroid cancer.
FOLLICULAR THYROID
CANCER
Other symptoms (rare):
pain,
stridor,
vocal cord paralysis,
hemoptysis,
rapid enlargement.
These symptoms can be caused by
less serious problems.
FOLLICULAR THYROID
CANCER
At diagnosis, 10-15% of
patients have distant
metastases to bone and lung
and initially are evaluated for
pulmonary or osteoarticular
symptoms (eg, pathologic
fracture, spontaneous fracture).
MANAGEMENT OF
FOLLICULAR THYROID
CANCER
Follicular carcinoma should always
be treated with total
thyreoidectomy.
A completion thyreoidectomy
should always be performed in
patients who have undergone a
lobectomy for a presumed benign
tumor that proved to be follicular
carcinoma at definitive histology.
MANAGEMENT OF FOLLICULAR
THYROID CANCER AFTER
SURGERY
Perform postoperative
scintiscan of the neck after 4-6
weeks.
If thyroid tissue is present, a
dose of radioactive iodine is
administrated to destroy
residual tissue.
MANAGEMENT OF FOLLICULAR
THYROID CANCER AFTER
SURGERY
Repeat scintiscan 6-12
months after ablation and,
thereafter, every 2 years.
Radioactive iodine may
ablate the metastatic tissue
in the lungs and bone.
MANAGEMENT OF FOLLICULAR
THYROID CANCER AFTER
SURGERY
Perform thyroid hormone
suppression in all patients
with total thyroidectomies
and in all patients who have
had radioactive ablation of
any remaining thyroid tissue.
MANAGEMENT OF FOLLICULAR
THYROID CANCER AFTER
SURGERY
A patient who has had a
thyroidectomy without parathyroid
preservation will require vitamin D
and calcium for the rest of their
life.
Evaluate thyroglobulin serum
levels every 6-12 months for at
least 5 years.
FOLLICULAR ADENOMA
It is benign neoplasm.
No differentiation is possible
between adenoma and carcinoma
by cytology or in most cases even
by frozen section.
Capsular and vascular invasion
are key features that distinguish
between benign and malignant
follicular proliferation.
HÜRTHLE CELL
CARCINOMA
WHO 1988: oxyphilic variant
of follicular carcinoma.
It may be also Hürthle cell
variant of papillary thyroid Ca.
Some authors classify it
separately as Hürthle cell
carcinomas.
HÜRTHLE CELL
CARCINOMA
Although preferentially classified
among follicular tumors, Hüthle
cell carcinomas are usually more
aggresive and metastasizing,
and they are less prone to take
up radioiodine and produce
thyroglobulin than well-
differentiated thyroid
carcinomas.
ANAPLASTIC CANCER
Peak onset age 65 and older.
Very rare in young patients.
Males more common than
females by 2 to 1 ratio.
Can occur many years after
radiation exposure.
Typically presents as rapidly
growing neck mass.
ANAPLASTIC CANCER
Spread to lymph nodes of the neck
present in more than 90% of cases.
Distant spread (to lungs or bones)
is very common even when first
diagnosed.
Overall 5-year survival rate is
reportedly less than 10%, and
most patients do not live longer
than a few months after diagnosis.
ANAPLASTIC CANCER
SYMPTOMS
A rapidly growing neck mass
Dysphagia
Cough
Neck pain
Dyspnea
Patients with metastases also may
note bone pain, weakness, and cough
Neurologic deficits may be observed
with brain metastases.
ANAPLASTIC CANCER
SURGICAL CARE
Perform surgery in
conjunction with radiation
and chemotherapy.
Use surgery to obtain a
definitive diagnosis when fine
needle aspiration is
unsuccessful.
ANAPLASTIC CANCER
Despite the typically large
size of these tumors,
extent of resection is
limited when diagnosis is
made.
ANAPLASTIC CANCER
Rather than performing complete
thyroidectomy, resect as much
thyroid tissue as possible without
attempting resection of all
adjacent structures because of
the high incidence of
postoperative morbidity (eg,
vocal cord paralysis, esophageal
fistula).
ANAPLASTIC CANCER
FURTHER INPATIENT CARE
Radiotherapy:
Despite the fact that ATC is
largely radioresistant, use
external beam radiotherapy
for local control.
ANAPLASTIC CANCER
Chemotherapy:
Currently, no available
chemotherapeutic agent or combination
of chemotherapeutic agents shows
sufficient antineoplastic activity to
prevent death;
yet in rare instances, chemotherapy may
prolong life by a few weeks or perhaps
months.
Doxorubicin and cisplatin are the two most
common agents used.
MEDULLARY THYROID
CANCER
A distinct thyroid carcinoma
that originates in the
parafollicular C cells of the
thyroid gland.
These C cells produce calcitonin.
Females more common than
males
(except for inherited cancers).
MEDULLARY THYROID
CANCER
Regional metastases (spread
to neck lymph nodes) occurs
early in the course of the
disease.
Spread to distant organs
(metastasis) occurs late and
can be to the liver, bone,
brain, and adrenal medulla.
MEDULLARY THYROID
CANCER
Not associated with radiation
exposure.
Usually originates in the
upper central lobe of the
thyroid.
MEDULLARY THYROID
CANCER
Poor prognostic factors
include age >50, male, distant
spread (metastases), and MEN
II-B.
Residual disease (following
surgery) or recurrence can be
detected by measuring
calcitonin.
MEDULLARY THYROID
CANCER
FOUR CLINICAL SETTINGS
SPORADIC
Accounts for 80% of all cases of
medullary thyroid cancer
MEN II-A (SIPPLE SYNDROME)
bilateral medullary carcinoma or
C cell hyperplasia,
pheochromocytoma
hyperparathyroidism
MEDULLARY THYROID CANCER
FOUR CLINICAL SETTINGS
MEN II-B
medullary carcinoma
pheochromocytoma
an unusual appearance which is
characterized by mucosal
ganglioneuromas (tumors in the
mouth) and a Marfanoid habitus.
hyperparathyroidism (uncommon)
INHERITED MEDULLARY CARCINOMA
WITHOUT ASSOCIATED
ENDOCRINOPATHIES.
Endocrine diseases occuring
together in different endocrine
glands are due to multiple, mostly
hereditary benign and malignant
neoplasms or hyperplasia with
excessive function (MEN=MEA),
or develop in response to an
autoimmune reaction affecting
different endocrine and perhaps
other glands
(autoimmune polyglandular
syndromes =APS)
AUTOIMMUNE POLYGLANDULAR
SYNDROMES
TYPE 1 = Blizzard’s TYPE 2 = Schmidt’s
syndrome syndrome
Major components: Major components:
Chronic Autoimmune thyroid
mucocutaneous disease
candidiasis Type 1 diabetes
Hypoparathyroidis melltus
m Addison’s disease
Addison’s disease Premature ovarian
+ other failure
endocrinopathies + other endocrinopathies
and features and features
MEDULLARY THYROID
CANCER
SYMPTOMS
a lump at the base of the
neck, especially during
swallowing;
hoarseness, dysphagia, and
respiratory difficulty;
MEDULLARY THYROID
CANCER
SYMPTOMS
various paraneoplastic
syndromes, including Cushing or
carcinoid syndrome
(uncommon).
Diarrhea secondary to high
plasma calcitonin levels.
Distant metastases.
MEDULLARY THYROID
CANCER
WORKUP
Serum calcitonin levels.
Pentagastrin-stimulated calcitonin
levels.
DNA testing for RET (it may
replace the diagnostic method
mentioned above).
24-hour urinalysis for
catecholamine metabolites.
MEDULLARY THYROID
CANCER
WORKUP
Screening for the development of
familial MCT in family members of
patients with history of MCT or MEN
2A or 2B.
Screen all family members for
missense mutation in RET in
leukocytes.
MEDULLARY THYROID
CANCER
WORKUP
A cervical ultrasound
(to detect LN metastases).
CT scan, MRI, and bone scans.
Fine needle aspiration.
MEDULLARY THYROID
CANCER
MANAGEMENT
All patients should receive total
thyroidectomy, a complete central neck
dissection (removal of all lymph nodes
and fatty tissues in the central area of the
neck), and removal of all lymph nodes and
surrounding fatty tissues within the side
of the neck which harbored the tumor.
Radioactive iodine therapy is not useful.
MEDULLARY THYROID
CANCER
MANAGEMENT
Long-Term Follow
A yearly chest x-ray as well as
calcitonin levels.
