Transcript 12 th G. Rainey Williams Surgical Symposium What

12th G. Rainey Williams Surgical Symposium
What Operation for Thyroid Cancer?
Ronald Squires, MD FACS
Associate Professor of Surgery
Sections of General and Transplant Surgery
University of Oklahoma Health Science Center
TOTAL
THYROIDECTOMY
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Questions?
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Introduction
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First reports of thyroidectomy from School of Salerno in Italy in
1170
Johann Dieffenbach of Berlin in 1848 stated that thyroidectomy
was “one of the most thankless and most perilous undertakings”
in surgery
Outcomes were so poor that the French Academy of Medicine
banned its practice in 1850
Billroth performed 59 thyroidectomies from 1861-1867 with a
40% mortality—a later series from 1877-1881 reported 16
thyroidectomies with 100% survival
Theodore Kocher won the Nobel prize in medicine in 1909 for his
contributions to thyroid surgery including many of the techniques
still used by modern day thyroid surgeons
Halsted first to advocate and popularize subtotal thyroidectomy
to preserve parathyroids and protect recurrent laryngeal nerves
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Thyroid Cancers
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Differentiated cancers
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Papillary carcinoma
Mixed papillary/follicular carcinoma
Follicular carcinoma
Hürthle cell
Medullary carcinoma
Anaplastic carcinoma
Lymphoma of thyroid
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Thyroid Cancers
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Differentiated cancers
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Papillary carcinoma
Mixed papillary/follicular carcinoma
Follicular carcinoma
Hürthle cell
Medullary carcinoma
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Thyroid Nodule Workup
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50% of population over 50 years have an US
detectable thyroid nodule
Prevalence of nonpalpable clinically
significant (1-1.5cm) nodes is 2-3%
90% of all nodules reflect benign disease
Of the 10% of malignant nodules, 75% are
papillary and 15% are follicular
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Thyroid Nodule Workup
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Check TSH level
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If high, begin thyroid replacement until euthyroid
If low, nuclear scan to check for hyperfunctioning nodule
(very rarely malignant)
FNA with or without US guidance when euthyroid
Nodules greater than 1cm in two dimensions are
clinically significant
16% of patients with palpable nodules will have no
nodule visible by US and the vast majority will be
diagnosed with Hashimoto’s thyroiditis
In multinodular goiter, masses > 1cm should be
biopsied (5-13% risk of cancer in these larger lesions)
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Thyroid Nodule Workup
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FNA results should be limited
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Benign goiter
Malignancy
Follicular neoplasm
Nondiagnostic sample
Diagnostic accuracy
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Sensitivity > 92%
Specificity 91-98%
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Thyroid Nodule Workup
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Benign diagnosis
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Indeterminate diagnosis
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Reultrasound in 6 months
– If same or smaller, follow yearly
– If larger, (15% increase in size in two dimensions) then
repeat FNA
Repeat FNA in 3 months or consider using US guidance if
not previously used
Follicular cytology (80% benign disease)
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Thyroid scan (if “hot” nodule in euthyroid patient then
observe)
All cold nodules and hot nodules in hyperthyroid patients
should be removed
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The Science
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All recommendations are based on retrospective
series or multivariate analysis
Mathematical models are also utilized to extrapolate
data to existing populations
The incidence of thyroid carcinoma is 11,000 cases
per year in the US with 1,100 deaths
Given the good overall survival, a prospective study
would need at least 12,000 patients followed for a
minimum of 20 years to distinguish subtle therapeutic
differences
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Arguments for Total Thyroidectomy
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Radioactive iodine may be used to detect and treat residual
normal thyroid tissue and local or distant metastases
Serum thyroglobulin level is a more sensitive marker for
persistent or recurrent disease when all normal thyroid tissue is
removed
In up to 85% of papillary cancer, microscopic foci are present in
the contralateral lobe. Total thyroidectomy removes these
possible sites of recurrence
Recurrence develops in 7% of contralateral lobes (1/3 die)
Risk (though very low [1%]) of dedifferentiation into anaplastic
thyroid cancer is reduced
Survival is improved if papillary cancer greater than 1.5cm or
follicular greater than 1cm
Need for reoperative surgery associated with higher risk is lower
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Arguments against total thyroidectomy
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Total thyroidectomy may be associated with higher
complication rate than lobectomy
50% of recurrences can be controlled with surgery
Fewer than 5% of recurrences occur in the thyroid
bed
Tumor multicentricity has little clinical significance
Prognosis of low risk patients (age, grade, extent,
size) is excellent regardless of extent of resection
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Complications
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Hypoparathyroidism should occur in less than 2% of patients
Recurrent laryngeal nerve injury in virgin neck less than 0.5% of
patients
Superior laryngeal nerve injury in virgin neck less than 2% of
patients
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Papillary Carcinoma
Algorithm for Treatment of Possible PTC
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Papillary Carcinoma
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If FNA is suspicious for papillary ca but not
diagnostic then incidence is 54% cancer
Presence of microcalcifications on FNA
suggestive of papillary ca (36% sensitivity,
93% specificity, 76% accuracy)
Pts with confirmed or highly suspicious
intraoperative finding should receive total or
near total thyroidectomy (< 3 gm remnant)
Prophylactic node dissection not indicated
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Papillary/Differentiated Carcinoma
Node Dissection:
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Up to 80% of patients found to have asymptomatic positive nodes
during series of prophylactic neck dissections 1,2
Clinically significant disease only develops in less than 10% of
patients with microscopic lymph node metastases 1,3,4
Central node dissection should be carried out if central nodes are
enlarged and positive by frozen section
Ipsilateral modified neck dissection has been shown to reduce
regional recurrence without improving survival if enlarged cervical
node is positive by preop FNA or intraoperative frozen5
1
Am J Surg 122:464-471,1971
J Surg 18:359-367,1994.
3 Surg Clin North Am 67:251-261,1987.
4 Cancer 26:1053-1060, 1970
5 Textbook of Endocrine Surgery, WB Saunders, 1997, p90.
2 World
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Follicular Neoplasms
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14-29% are invasive cancer
Frozen section analysis can be misleading
Hallmarks of cancer are capsular or vascular invasion
Follicular CA more likely hematogenous spread
Worse prognosis associated with increased age and
stage at diagnosis compared to papillary
>4cm nodule is 50-60% likely invasive disease
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Follicular Neoplasms
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Resection of lobe/isthmus with careful
examination for gross invasion or nodal
disease
Await final pathology of lobe/isthmus and if
positive, return to OR for completion
lobectomy
Subsequent I131 treatment, TSH suppression
and monitoring of thyroglobulin (<2µg/l)
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Hürthle Cell Neoplasms
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More aggressive than other differentiated thyroid
carcinomas (higher mets/lower survival rates)
Decreased affinity for I131
Need to differentiate from benign/malignant
Cancer in 13-35% of Hürthle cell FNAs
65% of tumors > 4cm are malignant
If malignant, needs total thyroidectomy and I131 with
thyroglobulin assays
Mets may be more sensitive to I131 than primary
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Medullary Carcinoma
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Presents as either an inherited syndrome (20%) or as
an incidental event
More aggressive than the differentiated thyroid
cancers
Does not respond to I131
Multicentric in 20% of sporadic cases and in almost all
of inherited cases
Much more likely to invade lateral lymph basins
Need baseline CEA and calcitonin levels
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Medullary Carcinoma
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Familial cases positive for RET protooncogene mutation
If positive family history, then genetic testing
If MEN IIA or FMTC then total thyroidectomy
and central lymph node dissection between
ages of 5-6 years
If MEN IIB then total thyroidectomy and
central node dissection ages 6mos - 3 years
SURGERY IS ONLY EFFECTIVE THERAPY
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Medullary Carcinoma
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If persistent elevated CEA or calcitonin, CT
scan for residual disease (50% of pts)
Aggressive neck dissection advocated by
many if persistent disease
Consider laparotomy for possible liver mets
Prolonged survival with significant symptoms
not uncommon with widely metastatic disease
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Medullary Carcinoma
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Incidentaloma/Micrometastatic Disease
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Lesions detected by imaging or found after
surgery for unrelated indication
Thyroid nodules common in population (410% have palpable nodules any given time)
Female/male incidence 6.4 / 1.6%
12% detected by palpation vs. 45% by
imaging
Lesions less than 1 cm-observe
Lesions 1-2cm “gray zone”
Lesions > 2cm are NOT INCIDENTAL
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Incidentaloma/Micrometastatic Disease
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Consider suspicious features:
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Increased vascularity
Irregular margin
Central microcalcification
Cervical adenopathy
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Incidentaloma/Micrometastatic Disease
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Local Invasion of the Neck
Tracheal resection repaired primarily
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Local Invasion of the Neck
Crycoid invasion with local muscle flap reconstruction
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Local Invasion of the Neck
Vertical hemilaryngectomy
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Local Invasion of the Neck
Circumferential tracheal resection with primary anastomosis
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Summary
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Total thyroidectomy is surgery of choice for
differentiated cancer as well as medullary
carcinoma of thyroid
Consider subtotal (less than 2gms residual
tissue) if less experienced or hazardous
operative environment
No therapeutic advantage for total
thyroidectomy in setting of papillary
microcarcinoma
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Questions
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