Transcript Carotid body tumors (CBT)

Management of
Carotid Body Tumors
Nadir Ahmad, MD, FACS
Division Head/Associate Professor of Surgery
Otolaryngology-Head & Neck Surgery
Cooper University Hospital & Medical School
Director, Head & Neck Cancer Program
MD Anderson at Cooper Cancer Center
Disclosure
No conflicts of interest to disclose
Carotid body tumors (CBT)
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Rare tumors (In US, 1-2 per 100,000)
60-65% of paragangilomas in H&N
Overwhelmingly benign (90-95%). M:F ~1:1
Malignant CBT
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Not a pathologic diagnosis, nor based on aggressive behavior
Presence of metastases to cervical LNs or distant sites
 Arise from carotid body with adventitia at medial
aspect of carotid bifurcation
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Carotid body arises from neural crest
Responds to acute fluctuations in concentrations of O2 and CO2, as well as
pH
Protects organs from hypoxic damage thru release of neurotransmitters
that help regulate ventilator rate
Carotid Body
 Small, reddish-brown, oval structure in the
posteromedial aspect of the bifurcation
 Although considered subadventitial, actual location is
periadventitial
 Feeder vessels from
ascending pharyngeal
artery thru Mayer’s
ligaments
 Innervated by Hering
nerve branch of IX
Carotid body tumors (CBT)
 Classification
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Sporadic
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Most common (85%)
Familial
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More common in younger pts (2nd-4th decade)
More often bilateral and multiple (5% of CBT are bilateral)
Gene for familial paragangliomas (PLG1) at the 11q23 locus
Gene is transmitted in AD pattern with genomic imprinting
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Hyperplastic
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Affected man has 50% chance of having affected child
Affected woman will not have affected child but can pass inactivated gene to next
generation
Arises in patients with chronic hypoxia (ie. COPD, cyanotic heart disease),
including those living in high altitudes
Occasionally associated with syndromes that have non-paraganglionic
tumors (MEN type II, VHL, NF-1)
CBT
 Typically present in mid-life as asymptomatic, nonfunctional, lateral neck mass (soft, nontender, pulsatile)
 Median age of onset – 45 yrs
 Slow-growing (doubling time ~7 yrs, median growth of
0.83mm/yr
 Typically vertically fixed because of attachment to
carotid bifurcation (Fontaine sign). Can have associated
bruit
 ~10% present with CN palsy
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IX, X, XI, superior laryngeal nerve, sympathetic chain
Sxs: pain, dysphonia, dysphagia, Horner’s syn,
tongue paresis, shoulder dysfunction, FUO
CBT - Workup
 Functional tumors are rare
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Check serum and urine catecholamines
Symptoms similar to pheochromocytoma (paroxysmal HTN, palpitations,
diaphoresis)
 CBT is an imaging diagnosis! Don’t do FNA.
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Initial imaging: US, color Doppler, CT with IV contrast, MR
CT – splaying of ICA and ECA
MRI – classic ‘salt and pepper’ appearance on T-1 weighted images
‘salt’ –
slow flow or
hemorrhage thru
tumor
‘pepper’ –
high velocity arterial
branch flow voids
CBT - Workup
 CT angiography
 MR angiography
 Conventional angiography
CBT – Historical perspective
• Earliest successful resection in 1903 by Scudder
• Significant complications up till 1960-70s leading
Hayes Martin to recommend against resecting
extensive CBT (Shamblin III)
• Advances in imaging & surgical techniques have vastly
improved safety & success of operation
CBT - Staging
 Shamblin classification – 3 types
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Type I
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Type II
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Small localized tumor easily dissected from adjacent vessels in peri-adventitial
plane
Larger, more adherent tumors, with partial surrounding of vessels
Type III
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Completely surround/encase bifurcation
Pre-treatment details & counseling
 Factors to consider
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Does the tumor need to be treated at all? What is consequence of leaving
tumor alone?
What is the health & functional status of the patient?
If considering treatment, surgery or XRT?
If considering surgery, is preoperative embolization or balloon occlusion
test needed? Does a vascular surgeon need to be involved?
What are the potential complications from XRT or surgery?
ANSWERS:
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Thorough understanding of the natural history/behavior of the tumor
Thorough understanding of the risks of treatment as well as observation
Thorough understanding of pre-treatment genetic counseling in the case of
familial tumors and pre-treatment physiologic management in the case of
functional tumors
Thorough understanding of the surgical techniques that minimize morbidity in
the event that surgery is selected by patient
Pre-treatment details & counseling
 MOST IMPORTANT POINT
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Multidisciplinary management
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Surgeon (Head & Neck)
Surgeon (Vascular)
Interventional Radiologist
Radiation Oncologist
Neurologist
Primary care physician
Speech/Swallow Therapy
 ENSURES THAT PATIENT HAS SOLID UNDERSTANDING
OF TREATMENT OPTIONS AND POTENTIAL
OUTCOMES AND RAMIFICATIONS, AND IS EMPOWERED
WITH RESPECT TO THEIR CARE.
CBT - Management
 Observation is not recommended for most tumors as
further growth & compression can ensue. However,
patient preference is paramount
 In most centers in the US, surgery is preferred treatment
modality. Surgery should be rendered in high-volume,
tertiary care centers
 Radiation therapy is generally reserved for elderly pts,
poor surgical candidates, pts with multiple paraganglia
in whom surgery would be highly morbid, and in pts with
recurrent tumors
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Highly debated
Often not radiosensitive (generally goal is not cure but to slow/halt progression)
Can regrow after suppression
Difficult to resect after XRT due to fibrosis.
Concern for XRT-induced tumors (esp in young pts), carotid artery disease, ORN
CBT - Management
 Surgery
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Ideal for tumors < 5cm & in young and/or healthy patients
Difficult in larger, Shamblin type III tumors. Operative risk directly related to
size & extent of tumor
Most often achieved via transcervical approach
Can be associated with cranial nerve palsies (classically IX, X) so preop
counseling very important with contingency plan for rehab postop
Must discuss other risks with patient (bleeding, infection, need for grafting,
stroke, death)
Preoperative embolization +/- balloon occlusion test is controversial
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Considered typically in Shamblin type II & III tumors to ↓ intraop bleeding
Preop embolization done 48-72 hrs preop before fibrosis sets in
Plethora of studies/reports do not show decrease in operative time, length of
hospital stay, intraop blood loss or increase in cranial neuropathies
Helpful in larger type II and all type III tumors, including balloon occlusion test
~5% risk of stroke in CBT surgery
CBT - Management
 Surgery
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For large tumors (Shamblin II & III), always involve vascular surgeon to be
on standby should a bypass graft be needed. This rarely occurs but is also
helpful from medico-legal perspective
Bilateral tumor resection associated with greater morbidity, including risk
of baroreceptor reflex failure (labile BP difficult to control medically).
Staging surgery is best option, with consideration of XRT if initial surgery
resulted in complications)
Intraoperative details & pearls for successful operation
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Strong headlight illumination & loupe magnification
Pre- and intra-op communication with Anesthesiologist
Need good assistant! Bipolar cautery & suction (provision for 2 suction setup)
Proximal & distal control of vessels
Meticulous dissection in peri-adventitial plane (Plane of Gordon-Taylor) with
knife or atraumatic dissecting instrument (McCabe) – helps minimize problems
Postoperative admission in ICU or Stepdown Unit to monitor for postop
hemorrhage or late CVA
CBT – Surgical complications
 Cranial neuropathy
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Most commonly injured CN – Superior laryngeal branch of X
Vagus injury - Aspiration/dysphagia/dysphonia
XI – shoulder pain/weakness; XII – tongue weakness/dysphagia;
sympathetic chain – Horner’s syndrome
 First Bite Syndrome
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Disruption of sympathetic innervation to ipsilateral parotid gland
Difficult to treat – NSAIDs, Neuropathic pain meds (Gabapentin, TCA,
Tegretol), Botox A intraparotid injection, anticholinergics, reassurance
 Baroreceptor reflex failure
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Loss of bilateral Hering nerves
Labile HTN
Sympatholytics/Clonidine
 Stroke
Conclusions
 Multidisciplinary pre-treatment evaluation is
paramount to treatment success
 Surgery remains the best treatment modality
 Surgeon must employ meticulous surgical technique
 Preoperative embolization & balloon occlusion test is
controversial & can be considered in larger tumors
 Understanding postoperative complications is
essential for patient counseling