Transcript Thyroid Cancer

Thyroid Cancer
Steven W. Harris MHS, PA-C
Epidemiology
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Annual Incidence of 23,600
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3:1 female to male ratio
Increases with age
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2% of clinically detected malignancies
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14th Most common malignancy in the US
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Falls behind:
 Lung
 Breast
 Prostate
 Colon
 Pancreas
 Bladder
2003 Estimated US Cancer Cases*
Men
675,300
Women
658,800
32% Breast
Prostate
33%
Lung & bronchus
14%
Colon & rectum
11%
Urinary bladder
6%
6%
Melanoma of skin
4%
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Non-Hodgkin
lymphoma
Kidney
3%
Oral Cavity
3%
Leukemia
3%
Pancreas
2%
All Other Sites
17%
12% Lung
& bronchus
11% Colon
4%
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& rectum
Uterine corpus
4% Ovary
4%Non-Hodgkin
lymphoma
3%
Melanoma
of skin
3%
Thyroid
2%
Pancreas
2%
Urinary bladder
20% All
Other Sites
*Excludes basal and squamous cell skin cancers and in situ carcinomas except urinary bladder.
Source: American Cancer Society, 2003.
So WHY are we discussing this today?
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Additional epidemiology
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Incidence of thyroid cancer is growing faster
than any other malignancy
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Treatment is highly effective
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3.8 % annual increases from 1992 to 2001
> 95 % of all patients survive
> 300,000 thyroid cancer survivors in the US
All require monitoring for recurrent disease
PLUS…
So WHY are we discussing this today?
Thyroid Gland Anatomy
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Largest endocrine gland, very vascular
Anterior and lateral sides of trachea
2 large lobes connected by isthmus
Thyroid Physiology
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thyroid hormone secretion
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controlled by TSH
hormones:
 Thyroxine
(3,5,3’,5- Tetraiodothyronine) T4
 greatest amount of thyroid hormone
 Triiodothyronine ( 3,5,3’, L-triidothyronine) T3
 most biologically active
 liver also converts T4 into T3 (80% of T3 via
liver)
 Reverse-Triiodothyronine
active thyroid hormone
RT3 minor biologically
Thyroid Anatomy & Physiology
thyroid hormone production strictly
dependent on Iodine
 90% of body stores of Iodine found in
thyroid gland most of which is bound to
thyroglobulin
 from dietary sources ~700ug day
 thyroglobulin in thyroid gland traps iodide
and oxidizes into iodine
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Thyroid Hormone Effects
General Characteristics
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Papillary carcinoma
76%
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Follicular carcinoma
16%
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Medullary carcinoma
4%
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Lymphoma/metastatic
3%
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Anaplastic carcinoma
1%
Distinguishing Characteristics.
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Papillary carcinoma
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Follicular carcinoma
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Hematogenous metastasis
Medullary carcinoma
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Lymphatic Metastasis
Least aggressive
Associated with increased dietary iodine
flushing, pruritus, and diarrhea
Associated with MEN-II
Anaplastic carcinoma
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Generally pts over 60
Most Aggressive
Etiology and Pathogenesis
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Genetic Predisposition
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Familial syndrome
 Familial adenomatous polyposis (APC gene
mutation)
 Cowden syndrome: hamartoma (PTEN gene
mutation)
 Familial isolated papillary thyroid cancer
 Familial Multiple Endocrine Neoplasia
 MEN-II
10 % of all thyroid cancers
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Etiology and Pathogenesis
Thyroid irradiation
 Accidental radioiodine exposure
 Radiotherapy: tonsillitis, lymphoma
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Radioactive iodine fallout (I-131)
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Common prior to 1950s
http://www.cancer.gov/cancer_information/doc.aspx?vie
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Unknown
Controversial Evidence
Preexisting benign thyroid conditions
 Parity
 Estrogen therapy
 Therapeutic radioiodine exposure
 Dietary Factors
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Iodine intake
more papillary cancers in populations with
generous dietary iodine content.
Presentation
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Common
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Painless neck swelling
Palpable solitary nodule
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Fixed
Stony/hard
Euthyroid
Incidental finding
Ipsilateral cervical
lymphadenopathy
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Less common
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Pain
Hoarseness
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anaplastic
Hemoptysis
Dysphagia
A nodule or a NODULE?
Nodules found in 6% of females and 2%
of males
 5% - 10% are malignant
 Increased suspicion
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Enlargement over weeks to months
Decreased suspicion
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Stable size
Sudden appearance: hemorrhage
Workup of a nodule
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TFT
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Ultrasound
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solid or cystic
Thyroid scan
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usually normal
hot or cold
FNAB
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histology
Thyroid Ultrasonography
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dimensions of thyroid lobes or nodules
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down to 1 mm
<1 cm no clinical significance
solid, cystic, or mixed
 suggests if papillary adenocarcinoma
 used for monitoring nodules
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growth (i.e. not “normal tissue”) during TSH
suppression, may prompt repeat biopsy or surgery
Thyroid Imaging: Radionuclide Scanning
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technetium (99mTc) or isotope of iodine (131I)
 99mTc can be concentrated, but not bound to TBG
and thus not stored in colloid, so some cold nodules
can appear warm
 131I –both concentrated & organified to TBG; scan
24 hours after oral 131I
 qualitative-size
 quantitative-uptake
 used to determine if nodule “Hot” or “Cold”
 almost all cancers are cold however most benign
lesions cold also
 replaced by fine needle biopsy as TOC for nodule
work-up
FNAB
Cold Nodule
Treatment: Papillary/Follicular
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Total or near-total thyroidectomy
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selective lymph nodes vs. radical neck
dissection
Adjunctive Radioactive Iodine ablation
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Residual disease
TSH stimulation
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thyroid hormone withdrawal
Recombinant TSH
Increased TSH, increases residual thyroid
tissue uptake of Iodine
Treatment cont.
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TSH suppressing thyroid hormone therapy
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Euthyroid
Suppression of tumor recurrence
Long-term follow-up to detect recurrent
disease
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Circulating serum thyroglobulin
Thyroid ultrasound
CT of chest
Whole body scan
Repeat surgery
Treatment: Medullary
Thyroidectomy
 Thyroid replacement therapy
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Not TSH suppression
Monitor with serial serum markers
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Calcitonin
CEA
Repeat surgery
External beam radiotherapy
Treatment Lymphoma
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Lymphoma
combined
chemotherapy and
radiation therapy
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Anaplastic
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typically nonresectable
treated with combined
external-beam
radiotherapy and chemo
therapy.
Only in exceptional
cases, however, do
these interventions
significantly alter the
grim prognosis.
Complications
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Natural Course
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Hoarseness
Dysphagia
Dyspnea
Esophageal
strangulation
Malnutrition
Pulmonary failure
Paresis
Bony fractures
Neurological cons.
Thyrotoxicosis
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Treatment
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Hoarseness
Hypoparathyroidism
Radioiodine
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Gastritis
Sialoadenitis
 Dental caries
 Dry mouth
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leukemia
Prognosis: post therapy
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High survival rates
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98% Papillary
92% Follicular
80% Medullary
33% of papillary tumors recur
 Extracervical medullary CA is incurable
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Slow progression
Anaplastic cancers unfortunately can be
among the most aggressive and
treatment-resistant malignancies known
Monitoring
Evaluate thyroglobulin serum levels every
6-12 months for at least 5 years
 Repeat the nuclear scan 6-12 months
after ablation and, thereafter, every 2
years.
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Before the scan, levothyroxine must be
withdrawn for approximately 4-6 weeks to
maximize thyrotropin (TSH) stimulation of the
eventual remaining thyroid tissue
OR
rTSH two days before scan
Check those thyroids!