Investigation of a Solitary Thyroid Nodule Dr. Sam Bugis Endocrine Surgery

Investigation of a Solitary
Thyroid Nodule
Dr. Sam Bugis
Endocrine Surgery
St. Paul’s Hospital
Solitary Thyroid Nodule
Palpable solitary thyroid nodules occur in
about 5% of the population
The harder you look, the more you find
Solitary Thyroid Nodule
Prevalence
• Females >> Males
• Increases with age
• May vary by geographic location
• Increases with exposure to ionizing radiation
Solitary Thyroid Nodule
Prevalence by Clinical Palpation
• Vander et al, Ann Int Med 1968
– 4.2% overall
– 6.4% of women
– 1.5% of men
• Turnbridge et al, Clin Endocrinol 1977
– 3.2% overall
Solitary Thyroid Nodule
Solitary Thyroid Nodule
Prevalence by Ultrasound
• 50% of the population will have one or
more thyroid nodules seen on U/S
Mazzaferri, NEJM 1993
• Only 6% of 1 cm nodules are palpable
• Only 50% of 1-2cm nodules are palpable
• Even 50-60% of >2 cm nodules are not
detected clinically
Brander et al, J Clin Ultrasound 1992
Solitary Thyroid Nodule
Prevalence by Ultrasound
U/S identifies multiple nodules in 16%-48%
of clinically solitary nodules
Tan et al, Ann Intern Med 1997
Brander et al, J Clin Ultrasound 1992
Walker et al, Br J Radiol 1985
Solitary Thyroid Nodule
Prevalence by Autopsy
• 49.5% incidence of nodules at least 1 cm in
a study of 821 palpably normal thryoid
glands
• 35% of nodules > 2cm were not identified
by palpation
• 4.2% were malignant
Mortensen et al, J Clin Endocrinol 1955
Solitary Thyroid Nodule
Differential Diagnosis
• Colloid nodule
• Adenoma
– Non functioning
– Functioning
• Cancer
– Primary
– Metastatic
• Cyst
– Mixed
– True
• Thyroiditis
• All the rest
Indications For Thyroid
Surgery (286 Patients)
SPH Jan 1/2001-Aug 30/2004
Cancer
Suspicion of Cancer
43%
16%
Goiter
Cyst
Hyperthyroidism
6%
20%
1% 5%
5%
4%
Subclinical
Hyperthyroidism
Completion
Thyroidectomy
Parathyroid Disease
Final Pathological Diagnosis in
125 Patients Operated on for
Suspicion of Cancer
Benign
72%
3%
Follicular Carcinoma
Papillary Carcinoma
12%
1%
12%
Microscopic Focus
Papillary Carcinoma
(<1cm)
Lymphoma
Solitary Thyroid Nodule
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Indications for Surgery
Malignancy
Compressive symptoms
Recurrent nodules
Hyperthyroidism
• Clinical
• Sub-clinical
• Cosmesis
Investigation of a Solitary
Thyroid Nodule
5% of solitary thyroid nodules are cancer
How do we find them?
Investigation of a Solitary
Thyroid Nodule
Assessment of risk
FNAB
Other investigations
Investigation of a Solitary
Thyroid Nodule
Investigation of a Solitary
Thyroid Nodule
Clinical Risk Factors
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Age
Sex
Symptoms
Physical findings
Family history
Radiation history
Investigation of a Solitary
Thyroid Nodule
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Symptoms
Hoarseness
Dysphagia
Hemoptysis
Rapid growth
Physical findings
• Hard, fixed
• Lymphadenopathy
• RLN palsy
• Single vs multiple
Investigation of a Solitary
Thyroid Nodule
Family History
Familial non-medullary thyroid cancer (NMTC)
• Up to 5% of non-medullary cancers
• 2 (or 3) direct relatives without other syndromes
• More aggressive than sporadic disease
• 2 types: Papillary >>> Hurthle cell
Investigation of a Solitary
Thyroid Nodule
Family History
Familial adenomatous polyposis
• Females age 25-35 at highest risk
• Disease is multifocal and bilateral
Cowden disease
• Hamartomas at various sites
• Cancers of thyroid and breast
Investigation of a Solitary
Thyroid Nodule
Family History
Familial Medullary Thyroid Cancer (MTC)
• 25% of all MTC
• Familial MTC alone or in MEN syndromes
• Ret oncogene point mutation on chromosome 10
• Recommendations for management
Investigation of a Solitary
Thyroid Nodule
Radiation Exposure
• External irradiation to the neck in childhood
increases risk of benign and malignant thyroid
nodules
• Risk is greatest in those exposed at the youngest
age
• Risk increases linearly up to 1500 cGy
• Females are at greater risk than males
• Many controversies about screening and follow up
Investigation of a Solitary
Thyroid Nodule
• TSH
• FNAB as part of the physical exam
• +/- Ultrasound
• +/- Nuclear Scan
• +/- CT, MRI
Investigation of a Solitary
Thyroid Nodule
What is the role of Ultrasound for a palpable
solitary thyroid nodule?
“the ultrasound machine to the
endocrinologist evaluating a thyroid nodule
is analogous to the stethoscope of the
cardiologist”
Weiss and Lado-Abeal, Curr Opin Oncol 2003
Investigation of a Solitary
Thyroid Nodule
What is the role of Ultrasound for a palpable solitary
thyroid nodule?
• To confirm the thyroid as the tissue of origin
• As a guide to FNAB for a mass that is difficult to
feel
• To objectively measure size in patients being
followed with or without thyroid suppression
• For follow up/screening in patients with radiation
exposure
Investigation of a Solitary
Thyroid Nodule
• 80-90% of all
nodules
• 10-20% are cancers
• Routine use is not
indicated
• 5% or less of all nodules
• <1% are malignant
• Used in patients with
suppressed TSH to identify
toxic adenoma
• Also used in indeterminate
FNAB
Investigation of a Solitary
Thyroid Nodule
CT and MRI
• No role in routine investigation
• In patients with established cancers or large
goiters, can assess involvement of
surrounding structures, retrosternal
extension and status of cervical lymph
nodes
Investigation of a Solitary
Thyroid Nodule
Thyroid Suppression
• Remains controversial
• Studies have suffered from:
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Non randomization
Heterogeneous groups
Inadequate TSH monitoring
Inaccurate measurement
Investigation of a Solitary
Thyroid Nodule
Thyroid Suppression
• Meta analyses suggest a trend toward nodule
shrinkage in treatment groups
• Overall, only 10%-20% of nodules respond
• Which patients?
• Predominantly solid nodules
• ? Abundant colloid
• ? Other factors
• Recognize risks
• Cardiac effects
• Effects on bone metabolism
Thyroid Incidentaloma
Thyroid Incidentaloma
Thyroid Incidentaloma
Definition: a nodule(s) unexpectedly
identified during an unrelated imaging
investigation or procedure
• Ultrasound is the commonest culprit
• Generally non palpable and < 1.5 cm
Thyroid Incidentaloma
“The thyroid is normal in size, the right lobe
measuring 3.2 x 2.0 x 1.5 cm. The left lobe
measures 3.4 x 1.8 x 2.1 cm and the isthmus
is 5 mm”
“In the right lobe are 3 nodules, one cystic,
the others mixed, with maximum diameters
of 3 mm, 7 mm and 9 mm. There are 2
similar nodules on the left side”
Thyroid Incidentaloma
“Cannot differentiate adenoma from
carcinoma, suggest nuclear medicine scan
and/or fine needle biopsy.”
Thyroid Incidentaloma
Who gets investigated?
• Size > 1.5 cm
• Clinical risk factors
Thyroid Incidentaloma
Who gets investigated?
• Family history
• MTC
• NMTC
• Radiation exposure
• One nodule 1.3 cms Æ FNAB
• Multiple nodules Æ observe +/- U/S or FNAB
Thyroid Incidentaloma
Who gets investigated?
Ultrasound features of malignancy
• Hypoechoic
• Irregular
• Microcalcifications
• Intra nodular vascularity
• Incomplete halo
Thyroid Incidentaloma
What size nodules and how many should be
targeted?
• 1.5 cm or larger – by consensus
• 1.0 cm or larger – ? arbitrary
• 0.8 cm or larger – Papini, J Clin Endocrinol
Metab 2002
• Up to 3 nodules – ? arbitrary
Investigation of a Solitary
Thyroid Nodule
Radiation Exposure
• All patients with childhood exposure should
be followed – the question is how?
• Clinically normal thyroid
• Regular exam, possibly U/S every 1-3 yrs
• Clinically palpable nodule(s) Æ FNAB
• Multiple nodules – follow up exam only, +/U/S, +/- FNAB, +/- surgery
Palpable solitary thyroid nodule
Normal TSH
Risk factor
assessment
Cold
FNAB
Benign Non Dx Suspicious
Suppressed TSH
Nuclear scan
Malignant
Hot
FNAB Treat re size
and hyperthyroidism
or
Observe Repeat
If follicular,
+/- U/S
+/- U/S Consider nuclear
Surgery
scan for low risk
+/- Thyroxine
Consider risk
Hot
Cold
assessment
Treat as above
Non palpable thyroid incidentaloma
> 1.5 cms
U/S guided FNAB
U/S features
Benign
Observe
Malignant
U/S guided FNAB
< 1.5 cms
Low risk
High risk
Observe
Physical exam
Follow up U/S
U/S guided FNAB
-up to how many
-down to what size
Solitary Thyroid Nodule
Prevalence by Autopsy
Conversely, 100% of thyroid glands dissected
at 2.5 mm intervals had papillary cancer
Harach et al, Cancer 1985
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