THYROID CANCER

1
THYROID CANCER
2

• Thyroid Cancer Type and Incidence
• Papillary 60-75
• Follicular 20-30
• Medullary 5-10
• Anaplastic 3

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.

4
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.

5
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)

6
ETIOPATHOGENESIS

• External irradiation of the neck
• (the latency period is at least 5 years)
• Iodine deficiency (Follicular Ca)

7
PAPILLARY CANCERThe 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

8
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)

9
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.

10
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.

11
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.

12
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

13
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).

14
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.

15
PAPILLARY THYROID CANCER LONG-TERM FOLLOW UP

• 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.

16
FOLLICULAR CANCERTHE 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)

17
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.

18
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.

19
FOLLICULAR THYROID CANCER

• Other symptoms (rare)
• pain,
• stridor,
• vocal cord paralysis,
• hemoptysis,
• rapid enlargement.
• These symptoms can be caused by less serious
  problems.

20
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).

21
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.

22
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.

23
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.

24
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.

25
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.

26
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.

27
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.

28
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.

29
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.

30
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.

31
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.

32
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.

33
ANAPLASTIC CANCER

• Despite the typically large size of these tumors,
  extent of resection is limited when diagnosis is
  made.

34
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).

35
ANAPLASTIC CANCERFURTHER INPATIENT CARE

• Radiotherapy
• Despite the fact that ATC is largely
  radioresistant, use external beam radiotherapy
  for local control.

36
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.

37
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).

38
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.

39
MEDULLARY THYROID CANCER

• Not associated with radiation exposure.
• Usually originates in the upper central lobe of
  the thyroid.

40
MEDULLARY THYROID CANCER

• Poor prognostic factors include age gt50, male,
  distant spread (metastases), and MEN II-B.
• Residual disease (following surgery) or
  recurrence can be detected by measuring
  calcitonin.

41
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

42
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.

43
Endocrine diseases occuring together in different
endocrine glands are due to multiple, mostly
hereditary benign and malignant neoplasms or
hyperplasia with excessive function (MENMEA),
or develop in response to an autoimmune reaction
affecting different endocrine and perhaps other
glands (autoimmune polyglandular syndromes APS)
44
AUTOIMMUNE POLYGLANDULAR SYNDROMES

• TYPE 1 Blizzards syndrome
• Major components
• Chronic mucocutaneous candidiasis
• Hypoparathyroidism
• Addisons disease
• other endocrinopathies and features

• TYPE 2 Schmidts syndrome
• Major components
• Autoimmune thyroid disease
• Type 1 diabetes melltus
• Addisons disease
• Premature ovarian failure
• other endocrinopathies and features

45
MEDULLARY THYROID CANCERSYMPTOMS

• a lump at the base of the neck, especially during
  swallowing
• hoarseness, dysphagia, and respiratory difficulty

46
MEDULLARY THYROID CANCERSYMPTOMS

• various paraneoplastic syndromes, including
  Cushing or carcinoid syndrome (uncommon).
• Diarrhea secondary to high plasma calcitonin
  levels.
• Distant metastases.

47
MEDULLARY THYROID CANCERWORKUP

• 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.

48
MEDULLARY THYROID CANCERWORKUP

• 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.

49
MEDULLARY THYROID CANCERWORKUP

• A cervical ultrasound
• (to detect LN metastases).
• CT scan, MRI, and bone scans.
• Fine needle aspiration.

50
MEDULLARY THYROID CANCERMANAGEMENT

• 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.

51
MEDULLARY THYROID CANCERMANAGEMENT

• Long-Term Follow
• A yearly chest x-ray as well as calcitonin
  levels.