Thyroid Cancer: Imaging and Surveillance - SD

Introduction

Good morning.
I'm Dr. Ed Grant, and I'm the chairman
of radiology department at the University
of Southern California and Los Angeles.

This morning I'm gonna be talking about
papillary carcinoma or cancer of the thyroid at least,
and the various ways to image both the primary tumor,
but with emphasis on postoperative surveillance
and intervention in this group of patients.

Good morning, I'm gonna be speaking about thyroid cancer
and imaging of both the primary tumors
and perhaps more importantly, the surveillance of patients
who have undergone thyroidectomy for thyroid cancer
and how this is employed today.

How it has changed over the years
and how various imaging techniques have become essential,
both in the follow up
and intervention on many of these patients as well.

Classification of Thyroid Cancers

When I think in terms of thyroid cancers, they're generally
differentiated into two different groups.
There are the so-called differentiated cancers,
which include papillary carcinoma, which is by far
and away the most common of all of the thyroid neoplasms,
follicular neoplasms and hurtle cell neoplasms.
And these are generally called neoplasms.
Because cytologically, it's impossible
to actually know which ones are benign
and which ones are malignant.
So they actually need to be removed in order
to make the diagnosis between benign and malignant.
So they're somewhat unusual in that respect.

The bad players are the ones below the line,
which are the undifferentiated cancers,
and these tend to include medullary and anaplastic cancers.
And of course, lymphoma may also affect the thyroid as well.

Increase in Detection of Thyroid Cancer

There's been a so-called epidemic
of thyroid cancer over the last 20 years,
with at least a 2.4 fold
increase in detected differentiated thyroid cancers.
When comparing the statistics from the seventies to those
of 2002,
I think most authorities would actually agree
that this really doesn't imply that there is a true increase
in the incidents of thyroid cancer,
but in fact, we are finding it in many,
many more patients in the past,
it generally took a palpable, large nodule to be detected,
but with imaging,
certainly additional nodules are now identified at
ultrasound and also many other imaging studies such
as carotid ultrasound, CT or MR of the spine
and neck, also identify many, many more thyroid lesions,
which then are potential candidates to be biopsied
and eventually proven to be cancer.

So I think there's really a much greater increase detection,
than there probably is an increase in the actual
incidents in the general population.

Also, another contributing factor
is the now aggressive biopsy of relatively small lesions,
and unfortunately, size doesn't really seem to matter in
that there is still a relatively high rate
of cancers in nodules that are smaller than one centimeter.
So really the size doesn't have a great deal of correlation,
and some series have actually shown that as many as 25%
of these small nodules may harbor cancer.
So that, again, it used to be thought
that you could biopsy based on the size of the lesion,
but that really doesn't seem to be a great way
to determine which lesions should be
biopsied and which should not.

I think it becomes kind of insane though as we start
to bi diagnose more and more cancers in smaller
and smaller lesions.

Also going along with the fact
that there's probably not a true increase in the incidences
of cancer in the population is that despite the fact
that we are now diagnosing many, many more cancers,
there is no significant change in the mortality rate,
for this particular relatively benign cancer.

As I mentioned, it's typically a very indolent tumor.
And there are good statistics showing
that there's probably greater than 95
or even 98% 10 year survival in patients, in fact,
in some cases without actual intervention
or removal of the lesion.

It is well known, however, that some cell types do tend
to be more aggressive, and I think eventually this is the
answer that needs to be found.
That is, which of these lesions actually needs to be treated
and which can probably be left alone
with very little problems going down the line.
Some re some lesions so-called tall cells,
other types may actually be more aggressive
and should be treated,
more aggressively than the routine benign
papillary carcinoma.

Another thing about thyroid cancers is that you remember,
they may recur many years
after their primary has been removed.
In some cases I think this actually has to do
with the fact that the metastatic disease really may have
been there all along and may not have been previously
detected by imaging techniques.

Also keep in mind
that the current surveillance algorithms are evolving quite
rapidly, with improvements in imaging
and certainly the increasing use
of biochemical tumor markers,
particularly thyroglobulin levels.

Initial Therapy and Follow-up

Now, the initial therapy for a patient diagnosed
with thyroid cancer is usually complete thyroidectomy,
as I mentioned before, follicular neoplasms
or herthel cell neoplasms
that have been diagnosed cytologically, will often go
to hemithyroidectomy at which point the lesion is removed.
It is then looked at to see if there is spread
beyond the capsule of the lesion,
and if there is, this implies that it's malignant
and usually the patient will be brought back
for a completion thyroidectomy.
Some places will actually perform a complete,
thyroidectomy regardless on these neoplasms.
At our institution at least, we tend to go
with the hemithyroidectomy first.

Many of these patients will undergo lymph node
dissection at the time of thyroidectomy,
and, preoperative imaging has shown that as many
as 30% of patients who have thyroid cancer will present
with positive lymph nodes in the neck at the time
of presentation.

Many patients will then undergo radio iodide ablation
therapy with the idea of essentially eliminating
all thyroid tissue in patients
who were proven to have cancer.

The vast majority
of differentiated thyroid cancers will occur in the local
or regional areas, basically in the neck.
Distant metastases are quite unusual though they do occur,
and again, as I mentioned, the idea of surgery
with postoperative radio iodine ablation is
that there would essentially be no residual thyroid tissue,
basically sono graphically.
There should be no thyroid tissue
or no tissue at all in either of the thyroid bed.
That area between the trachea
and the carotid artery should essentially be empty.

And, the beauty
of having essentially no thyroid tissue is one can then
monitor the patients with thyroglobulin levels
because again, there should be no thyroid.
There should therefore be no thyroid globulin
or the levels should be very, very low.
This can be used as an excellent way to identify
or suggest that there is in fact recurrent disease.

The one of the problems of course with imaging is
that lymph nodes are quite common in normal patients,
so the differentiation between metastatic lymph nodes
and lymph nodes that are just inflammatory
or just in in the normal neck, can be quite challenging
and something that's very important.

So the question is, who
and when do we image and how?
There are various techniques.
I 1 31 whole body scanning,
I think at one time was kind of the first line of defense.
There's the possibility of using CT or mr.
More recently pet usually now PET ct, may be used
to monitor these patients.
And it's one of those interesting situations
where ultrasound has now become extensively used in the
surveillance of patients who have undergone thyroidectomy
and has now probably become the primary
or first line imaging technique in monitoring
these patients after surgery.

What are the criteria for malignancy
and how do we confirm it?
We'll talk a bit more about that.

The frequency of follow up is, again,
not well determined, at least on a scientific basis.
And then of course, there's the question
of do we really care?
And I think at this point people are realizing that
this disease has become so common now
that we're finding it in the general population.
It's a very indolent disease
and really how aggressive do we want to be with
what are small recurrences,
and what would really be the natural history.
And I think these are things that need
to be worked out over the next couple years,
lest we waste entire, large amounts
of money in both following and fi following these patients
and finding smaller and smaller lesions that are primaries.

Imaging Modalities

I-131 Whole Body Scanning

Now, the older literature, again, as I mentioned,
would've stated that the I 1 31 whole body scan
is probably the primary imaging technique,
and I think that that's clearly no longer the case.
It was said in the early days
that routine scans would be performed at six and 12 months
after ablation,
and if the patient had two consecutive negative scans,
they had a greater than 95% chance of 10 year survival.
I think the reality of it is just about everybody
who has thyroid cancer at least differentiated,
probably has a greater than 95% chance of 10 year survival.
So I'm not sure that's particularly helpful.

The drawbacks to the I 1 31 whole body scan is
that it has a relatively low sensitivity
for recurrent disease after radio iodide ablation.
The anatomic detail is really too poor
for surgical planning.
It may be negative in dedifferentiated tumors
that just don't pick up the iodine,
and it's really quite well worked out now
that ultrasound is far more sensitive for the identification
of local recurrence.
One paper quotes ultrasound
as being 70% sensitive whole body scan as 20.
Personally I think ultrasound is probably far greater
than 70% sensitive for local recurrence in the neck.

The one thing that the iodine can do,
the whole body scan can do, of course,
is it can detect iodine concentrating distant metastases and
therefore it may be considered in the face of
elevated thyroglobulin levels
where the neck ultrasound is negative.
Again, people might say it could be considered in patients
at high risk for recurrence,
or clinical evidence of recurrence,
or aggressive tumor histology.
Again, as I mentioned, this is an examination
however that really has largely fallen out of favor.

CT

Ct, may be useful
and I think it's best use in patients with thyroid cancer
is in detecting distant metastases.
It's probably the best, if not definitely the best choice
for identifying lung disease and monitoring it.
Generally you should, consider high resolution CT
as, I will show in a moment.
This shows these very ary lesions far better than
routine chest ct
and it may be useful in treatment planning in large tumors
that may be invading local structures.
It's really a poor choice for the surveillance
of routine cervical adenopathy.

While it does have reasonable resolution,
it really does require IV contrast
to optimize the identification of cervical nodes.
Also the contrast
and anatomic resolution in general is probably less than
that of ultrasound or mr.
And iodinated contrast media, which are required,
may be contraindicated in some of these patients.

For the nodes themselves.
Unfortunately, really the only criteria for
malignancy is size,
and I think it's very well established at this point
that it's common
to have lymph nodes less than one centimeter
that may be positive for malignancy.
So also there of course,
is the radiation dose in these patients.
These patients may be relatively young,
and so in that case it actually may be significant
as mentioned.

You may see lymph nodes in the neck quite readily with ct.
You can see some enlarged nodes here
on the right side of the neck.
On the sagittal reconstruction, you can see nodes.
So again, the CT can pick up the nodes.
The problem is it's really not good at differentiating
benign from malignant
and the optimum visualization
of the nodes requires contrast.

The one area where I think the CT really does hold its own,
of course, is in the chest.
You can see here a routine CT scan
and there's an indication
of these innumerable tiny little lesions all over the chest.
When you compare that,
however, with the high resolution ct,
of course it's really quite dramatic in this particular
woman who is otherwise, well, by the way, this is a woman
who has extensive disease in the chest,
but clinically you would never know it.
So, again, the actual history of some
of these patients may be unusual.
Why do some of these patients, a small number of them go on
to have this picture versus the vast, vast majority
that never metastasize
beyond the neck if they metastasize at all.

One of the other things that both CT
and MR can do that ultrasound is not as, fassal at
is the treatment planning in patients with large
or very invasive tumors.
Certainly, ultrasound is
of no value in looking at possible bony invasion,
or invasion of the soft tissue structure such
as the esophagus or the trachea in this patient
with a large anaplastic carcinoma shown here in the neck.
So again, for large lesions, extremely large lesions.
Treatment planning with CT is something
that certainly is feasible.

MR

Mr is also often the,
other technique of choice.
When it comes to pulmonary metastasis,
I don't think there's any question that CT is superior,
but for cervical imaging,
MR should be considered in some patients, again,
ultrasound is cheaper.
It has at least equal,
if not better resolution than MR for nodes.
That one centimeter rule, again, looking at the size
of the nodes may be problematic.

However, MR.
With contrast, does increase the specificity
for metastatic disease versus benign adenopathy.
It does require a specific neck coil.
I think most radiology
departments would have these available.
And just like ct, it is good for invasion
of surrounding tissues such as trachea
or nerves, when surgical planning is necessary.

Again, this is usually more applicable
to the more aggressive non-differentiated cancers rather
than the papillary types,
but again, you can get extremely dramatic
and excellent images of both primary tumors
and lymph node extension.
Here you can see a large papillary carcinoma in this young
woman on the right.
You can see these lymph nodes on both sides of the neck.
Here with contrast injection, you can see
that there is peripheral enhancement,
and, lower levels of enhancement centrally, typical
of Ben, of of, of malignant nodes, in these patients.
Again, very nicely seen with low density centers here
after contrast injections.
So it does have that ability probably superior to, ct,
in, in this regard.

FDG PET

Now, FDG pet, again, as I mentioned, most
of these scans are now done as part of PET CT scans.
Has the advantage
of being basically hybrid registered images.
So you have the physiology of FDG PET
with the excellent anatomy of ct.
It, it may be superior to,
white blood cell counting
and some of the other imaging techniques,
when this is negative.

And it is said
that the more d differentiated tumors become
or metastatic disease becomes,
the less sensitive the iodine scans will be,
but the more sensitive FDG will be.
So that's something to keep in mind
where PET may actually be a valuable adjunct in
imaging these patients.

You do have the problem with false positives
with PET scanning and inflammatory processes
and in some normals,
and of course it cannot be used to direct biopsy.

This is just a plain PET scan without the PET
CT PET alone.
You can see that there's uptake here in, in some
of the nodes in the lower neck or upper thorax.
This is a typical picture of a positive PET scan.
This of course is PET ct.
You can see here in the thyroid bed
that there is an area of, increased uptake.
You can also see here that you have positive,
adenopathy in the upper mediastinum.
So the two of them, of course,
give you a much better picture of the metastatic disease
and exactly anatomically where the recurrence is located.

As I mentioned, you can have false positives.
Here's a false positive in a patient
with chronic thyroiditis.
Hashimoto's disease will often,
because of the inflammatory nature of it
actually cause a diffuse increase in tracer uptake in in
patients who do not have cancer.

One of the other, interesting facets of scanning
with pets, kind of the opposite situation in patients in
whom PET scanning is undertaken for
metastatic disease of another primary breast, lung,
any other primary that's being investigated with pet,
you will occasionally find a hotspot in the thyroid.
The literature would tell you that these are,
do have an increased incidence of cancer.
Typically, those are referred to ultrasound,
sometimes referred as incidentalomas on pet,
but these will often be referred to ultrasound for biopsy
and as I mentioned, do have a higher incidence of papillary
and other carcinomas, than the general population.
So it's probably a good idea for these patients to undergo.
Biopsy.

Ultrasound

Ultrasound, as I mentioned,
has become really the primary technique for both
preoperative imaging, basically identifying
and biopsying the original nodule.
And for post thyroidectomy surveillance,
it does have the advantages, of course,
that it is non-invasive, does not require contrast.
No radiation really has excellent, excellent contrast
and anatomic resolution in the neck.
It's much cheaper than MR and ct
and of course it provides an excellent guide for biopsy.

There is literature out there that will tell you that,
ultrasound may actually be positive,
when thyroglobulin levels remain negative
and that sometimes we see very tiny nodes
that may be positive by biopsy.

And again, the surveillance is not well worked out.
An excellent, review article by Cooper at all from 2006
suggests that after surgery follow up should be performed
with ultrasound at six and 12 months,
and then yearly for three to five years.
And again, exactly how how much you wanna stick to this,
is, is really up to probably up to the philosophy
of the referring MDs.
But this is something again, that's always controversial,
exactly when is the best time
to do surveillance given the benign nature
or indolent nature of the disease.
Again, some people may be a little more,
a little bit more conservative about performing follow up
than the, algorithm proposed here.

I believe
that the surveillance examination is somewhat more
complicated than the typical scan of the thyroid.
And in fact, when we see,
when we perform thyroid ultrasounds, we tend with,
with a positive outcome with a nodule.
We do tend to include the, lymph node areas
around the neck as we would for a surveillance scan
because again, 30% of patients
with papillary carcinoma will actually have nodal disease at
the time of presentation.

Like all other ultrasound examinations,
these scans are highly operator dependent.
There's a relatively longer learning curve, at least I think
so, and you really need a technologist
or physician who is really dedicated
and obsessive compulsive about finding these.
Oftentimes small
and multiple nodes within the neck,
obviously requires high resolution transducers.

Color doppler I think is an essential part of the,
or a helpful part of the examination.
You need a knowledge of the anatomy of the neck
and nodal anatomy of the neck, recurrence patterns,
and of course the differentiation
of benign versus malignant nodes is very important also.

Again, ultrasound, as I mentioned, is an excellent method
for biopsying these potentially positive nodes,
although I think biopsy of nodes tends
to sometimes be more challenging than biopsying of
thyroid nodules themselves.

The scan technique is similar to the typical,
nodule biopsy.
The neck is slightly extended.
Oftentimes I have the patient turn their head somewhat away
from the transducer,
but depending upon the location, it may actually be helpful
to have them turn their head toward you.
So again, that's variable.
And I usually see what makes the nodule
or the node, appear most accessible.

In patients who have a thick, heavy neck
or short neck or women with large breasts,
a pillow under the shoulders, not under the head
or the neck, but under the shoulders may help
to throw the chin up and
therefore make the access much easier for you.

As the person performing the biopsy,
we use the highest, linear array transducers
that will give us adequate pictures.
At this point, some of them go up
to 18 centimeter or mil megahertz rather,
but again, the center frequency can often be changed.
Some patients with big necks,
though they're very high resolution probes,
may actually give you more degraded images
than the lower ones.

The typical scan, we go from the clavicle bilaterally
to the submandibular areas.
We evaluate the thyroid bed bilaterally
for possible recurrent disease, a common area
for recurrent disease.
We take images in the transverse
and longitudinal, planes of all nodes, important
to optimize the gray scale characteristics.
You'll see why that's important in a moment,
and again, in nodes that are questionable.
We may throw color doppler on there.

Absolutely, in our opinion, you must have a technologist
or operator worksheet.
These patients come back year
after year for their, their scans.
Just looking at the ultrasound pictures themselves
will just drive you crazy.
You really need to have a worksheet where the images,
of the nodes and their location and size are put there.
We scan them into our packs so that they're part
of the record and are easily pulled up
for comparison year after year.
These patients will come back year after year,
and the worksheet is just absolutely essential.

As I mentioned, it's important to evaluate the thyroid
or a surgical bed, that area between
and behind the common carotid
and the trachea should be empty.
There should be no residual tissue there.

Unfortunately, it's impossible sono graphically
to know whether you're dealing
with residual tissue from a somewhat
botched thyroid surgery.
We often see patients from outside institutions
who come in or, or worse yet outside countries
where there is tissue there that actually turns out
to be residual thyroid that's not been removed.
So that's, that's not uncommon.
Unfortunately, it's impossible
to differentiate it in most cases from recurrent disease.
Typically, the thyroid,
residual thyroid tissue will tend to be more hyper coic
and relatively homogeneous.
Recurrent disease tends to be relatively hypoechoic.

It's important to evaluate the vessels,
for possible invasion.
I think ultrasound is a little less able to do
that when it involves the esophagus
or even more so the trachea.

The, the big thing though is the surgical bed
and the evaluation of the jugular venous chains bilaterally.
Any palpable lumps, of course should be scanned as well.
And many of these patients do come in
with palpable lumps.
They find a little lymph node that suddenly popped up
and become paranoid and want to have it evaluated.

There are various, classifications
of the cervical nodes, one shown here.
We actually have adapted our worksheet such
that the nodal levels are relatively
or not relatively easily visible on it.
Most of the nodes will occur in the area
of the thyroid bed, or, and
or in the level three
or four lymph nodes out here lateral to the carotid,
and in the area of the jugular vein, either medial
to the jugular vein
or immediately lateral to it,
often impressing on the jugular vein
because it's obviously a soft vein
and quite compressible by the surrounding nodes.

So it's a good idea to give your surgeons
as much detail about the location of these lymph nodes.
Again, we tend to do level two, level three,
level four nodes.
And I usually will also give them the location
of the node in relation to the adjacent carotid artery.
Is it at the level of the bifurcation?
These are usually benign.
Is it in the mid, mid distal or proximal?
One third in addition to the nodal level,
which may get a little confusing,
but, I think we all work out the communication we
need with the surgeons.
And again, if you're starting this examination,
it's very important to establish a good rapport
with your surgeons so that they know exactly
what it is you're doing and what you're saying
and you know exactly what it is they want to hear.

With regard to how to find these lymph nodes,
the worst thing you can do is diagnose lymph
lymphadenopathy, have the patient go back
for a lymph node dissection
and then have them come back for their follow-up
and look at the scan and say, oh God, there's that node
that I saw six months ago, and they obviously didn't get it.
So very important that the surgeons know very,
very well in whatever way you feel best to communicate
to them the locations of these enlarged lymph nodes.

Now, as I mentioned, the area between the carotid artery
and the thyroid or the trachea rather, should be empty.
They should have removed everything that's in there.
Here you can see these two hypoechoic areas
of recurrent disease.
This was biopsy and,
and shown to represent recurrent papillary carcinoma.
Again, the color doppler may make you feel a little more
comfortable about the fact that this is recurrent disease.
To me, I don't see a specific pattern with regard
to benign versus malignant disease.
Again, the malignant disease may be a little bit more
vascular, may be a little bit less organized than residual
thyroid, but we tend to rely upon the identification of,
of the, of the hypoechoic lesions by ultrasound
and then progress on to biopsy.

Criteria for Benign and Malignant Nodes

Now adenopathy, I think it's, again, very, very important
to differentiate for your referring clinicians,
the common benign nodules.
We have clinicians who absolutely insist.
I want to know what is your thought?
Is it benign or is it malignant?
You're getting paid for this examination? Commit to it.
If you can't, you can't in every case. So what's benign?

Small, small doesn't help us a whole lot.
You see small nodes all the time,
but certainly that one centimeter rule that we use on CT
or MR in the abdomen is not applicable in the neck.
It is absolutely well known
that when you say there's a sub centimeter node,
you're saying absolutely nothing.
'cause these nodes can commonly harbor malignant disease
even though they're less than one centimeter.
So if I ever see a resident
who says sub centimeter nodes in the neck,
I immediately beat them up
because that's just nothing that helps anybody in the neck.
It absolutely does not apply.

Shape is probably the most important factor of Ben Benignity
or important sign of benignity.
Small nodes, which are oval
or cylindrical in shape are gonna probably be benign.
We look for that hyper coic, fatty hilar region.
And of course, distal nodes tend to be benign.
Just about every patient, every normal subject will have,
in some cases pretty large submandibular nodes in
the majority of patients.
So luckily it's very, very unusual to find
isolated submandibular nodal involvement from
papillary carcinoma.
The only time you really see this is when there's extensive
adenopathy throughout the neck.
It may extend, distally,
but typically you see these nodes,
they're going to be benign.
Look for the hyper coic hilar region,
and again, they may be oval or cylindrical
and a little scary in the submandibular area
because they can be quite large.
Oftentimes they're bilateral.

Now malignancy is, is considered
when we see calcifications, calcifications,
punctate calcifications in lymph nodes,
is in my opinion, essentially diagnostic
of metastatic disease.
Likewise, when you see cystic lesions within the nodes,
this is very, very, ev evident
or very, very suggestive of malignant disease.
Again, well known when nodes become round,
when they're involved with malignant disease, they tend
to lose that oval or cylindrical shape.
And round marble like nodes are also often going
to be positive again, even if they're very small.
Some people do ratios between the transverse
and AP diameters.
I think you can look at these nodes
and know pretty well whether it's round or oval
or cylindrical.
Also in homogeneous
or diffusely echogenic lymph nodes are also highly
suspicious for representing recurrent disease.

Here's just a series of very, very tiny
long cylindrical nodes.
I don't think anybody would suggest
that these are of any concern.
This one is also cylindrical,
but a little rounder than the others that I just shown,
but I don't think anyone would be
particularly worried about this.
There is a small locus of echogenic hilar fat.
Again, another good sign that this is benign disease.

Again, another, relatively avascular node here,
which is nice and cylindrical.
I don't think anyone would have an issue with that,
even though it does not contain the, hope
for epigenic hilas.

Now, I think that can be contrasted
with this very bad series of, of findings in the neck.
Here you have a young woman
with a large mass in the thyroid itself,
multiple echogenic foci, typical
of the sonomas calcifications of papillary carcinoma.
You can see here the carotid artery
and jugular vein are sandwiched between the thyroid
and this relatively large in homogeneous lymph node.
Typical of a patient
who at presentation already has metastatic adenopathy.

This is a patient where we found a small, very, very round,
but quite small node in the supraclavicular area, which
by biopsy was proven to represent metastatic disease.

Some folks have stated that the color can be useful
in that benign nodes tend
to have a more regular branching pattern
from the hilar region.
Whereas malignant cervical adenopathy tends
to produce a less regular, less orderly pattern.
I find that a little difficult to apply, routinely.
We often do put color on,
but quite honestly, again, I tend to go with the shape
and gray scale appearance much more than I do the
color Doppler appearance.

I don't think anyone would have difficulty diagnosing
the echogenic foci within this as representing,
metastatic papillary carcinoma with calcifications.
The classic findings of a node with internal calcifications
here are somewhat more clump like,
calcifications in this node, which also,
again was biopsy proven
to represent metastatic papillary carcinoma.

Two of the other features of malignant nodes,
this one showing a focus of hypoechoic
or an coic cystic degeneration.
This is, again, very highly suspicious
for representing metastatic disease.
Here's a relatively echogenic lymph node,
sandwiched again between the jugular and the carotid artery.
Both of these were biopsy proven
to represent metastatic disease.

Again, a small, relatively round node,
but I think these calcifications would very,
very strongly suggest that this needs to be biopsied
and represents metastatic disease.

This is a patient with rather advanced disease.
You can see the carotid artery here sandwiched
between this large bed recurrence
and the more peripheral adenopathy.
Again, both of these masses demonstrate
internal calcifications.
Not a whole lot of question here,
but that this patient has relatively advanced metastatic
disease within the neck.

Ultrasound-Guided Biopsy Techniques

Now, as I mentioned, ultrasound guided biopsy is usually,
ordered before, intervening
or performing the lymph node dissection
to confirm the cell cells are present.
We get written informed consent.
We discuss the usual suspects such as bleeding
and infection, although I've really never seen an infection.
Bleeding is a real potential possibility
with either lymph node
or thyroid biopsy, although quite rare.

One thing that I have occasionally encountered,
with biopsy of nodes that I,
I don't believe I've ever actually done,
when a patient had the trachea
or had the thyroid present,
is actually puncturing the trachea.

Again, your, your picture will tend to sort
of blur out because the air dissects into the soft tissues
of the neck and then the patient will begin coughing up
blood, which is not a fun thing to encounter.
I think radiologists get really freaked out
by a little bit of blood, but the surgeons, if, if you are
that freaked out, we'll come and laugh at you
and say, oh, it's no big deal, it'll go away.
So, it does occur probably
because there's no soft tissue between,
the transducer
and the trachea.
It becomes more in the line of fire when you're trying
to get into some of these lymph nodes
that may be difficult in, in difficult locations.
But again, it's a self-limiting thing.
Reassure the patient, sit them up, reassure yourself.
It's really nothing to worry about
and it tends to go away very quickly.

In general, just as I do with a thyroid biopsy,
I localize the site, I put a mark on the skin,
sterilize the area with some Betadine.
I anesthetize there are those who don't.
I think sticking a needle into a patient's neck multiple
times makes me feel better,
at least if I believe the skin is anesthetized.
We put a transducer cover over the transducer.
Typically, we do three passes with a 25 gauge needle.
If you're lucky enough to have cytology actually on,
on site, which we're not, you may have them mounted
by the cytologist or mount them yourselves.

We always aspirate the fixative into the needle
and the syringe, which is very, very important.
They spin it down, make a cell button,
and, actually may get cells for slides out
of your aspirate.

Typically we do thyroglobulin washings,
and I'll talk a little bit more about that.
Although, quite honestly, my concern there is really
for the cost of that examination what it adds.
But we'll talk a little bit more about
that in just a moment.

We use a prepared kit for all of our neck biopsies.
Tend to use a 25 gauge needle
for the biopsies themselves.
I, I know that there's debate about the capillary action
of just putting the needle in.
I tend to be a big believer in, in suction,
so I use the suction gun.
The aspiration gun gives you very, very good control
of the needle and its position.
We do them freehand,
but I'm a very big believer in, in the suction gun.

Here's just a real time image, showing a biopsy
of the lymph node here adjacent to the carotid and jugular.

A lot of, not a lot of,
but some, clinicians, worry about doing these
because of the proximity to the carotid and the jugular.
Obviously, I don't wanna put a needle into either of them,
if necessary because of the location.
I have gone through the veins on purpose.
Remember, veins really don't bleed very much,
so it's nothing to worry about.
Again, prefer not to put a needle in the jugular,
but if you have to, you have to.

Here's another patient
with a very tiny node right here immediately anterior
to the, carotid bifurcation vessels.
Best to be careful in these patients.
You really don't wanna put
that needle into the carotid artery,
and a lot of times these structures are gonna
be right next to it.
And, and I get a lot of patients,
who are referred to me
and they say, oh, the doctor told me
that they didn't wanna put a needle next to the carotid,
but it's really nothing to worry about.

This is a patient who actually had lymphoma
with gross adenopathy.
We tend to use slightly larger needles,
but again, the 25 usually is sufficient.
I've never done core biopsies.
With, between the thyroglobulin
and some of the other tests that are now available,
we can get a pretty good, we do flow cytometry.
If there's a suspicion of lymphoma,
we can get a pretty good diagnosis
of lymphoma using flow cytometry without having to resort
to core needle biopsies.

I mentioned the problem of the carotid artery.
Somehow the tech managed to get this picture,
this nice picture of the needle being withdrawn
from the carotid.
The patient got up off the table, she went home
with absolutely no problem,
but I must admit, I got a little pale when I saw the needle
going right back through the carotid and out the other end.
But, we continued on, got our biopsy of the node
and the patient did quite well.

I do not like to use 22 gauge needles in
patients in whom there are nodes very close to the carotid.
I think 22 can be a lot more frightening.
20 fives, as you can see here, really will do no harm,
best to avoid the carotid.
But funny that I got a picture of one of them

Thyroglobulin Assays

thyroglobulin assays I think are worth discussing in that.
Remember, TG is, th globulin is produced
by thyroid tissue, both benign and malignant.
Therefore, if you get a positive lymph node aspiration,
it is presumptive evidence
that there is a metastasis present.

So there is literature out there that says that the use
of the thyroglobulin assay is actually more sensitive
than cytology alone.
So we have begun in the last couple of years
to do TG assays on all of our nodal biopsies.
Personally, I think that this is an expensive test
and has an extremely low yield.
If your cytologist is as good as mine,
we have excellent cytology.
It's very, very unusual for me
to get a negative result in one of these nodes.

There is, again, literature saying
that in cystic nodes it may be important.
These are pretty unusual.
And I think practically speaking,
this might be the only time
where I would consider doing thyroglobulin assays
unless I'm pushed by some of my clinicians
and I tend to be,

it really doesn't require an additional pass.
All you do is a washing of the needle
after you're done to get a little bit
of the material in saline
and then send it over for tg um, assay.
You do have to keep it refrigerated.

And again, if you have a cystic lesion
where theoretically you may not get cells for cytology
because you're getting cyst fluid, this may be a reason
to use thyroglobulin assay.
As I said, it's an expensive examination.

On most nodes I have gotten positive biopsies
and I, I really would wonder if it is something
that is truly of, of, of a great deal of help, again,
in the cystic lesions,
I think this is probably a good use for it.
But in general, adenopathy,
I don't think I can ever think of a case
where the thyroglobulin added anything,
although, as I said, there is some literature out there
that says that it may.

Ultrasound-Guided Node Ablation

Lastly,
I'm gonna speak about ultrasound guided node ablation.
Remember, we're talking about indolent disease.
We are now finding smaller
and smaller nodes, which are biopsy positive,
but again, it's really questionably significant.
Whether izing all these nodes, removing all these nodes,
chasing them is really helping the patient.

We have many patients that we've followed over a number
of years, with relatively small nodes
or bed disease
that have really not changed over several years of follow up
and are being conservatively watched by their clinicians.
And everyone is quite happy about that, at least in,
in this particular population.
Again, it depends upon the clinician and the patient.

Many of these patients,
however, will have had multiple surgery, radiation,
both diffuse and focal.
So going back in on these patients time
and time again becomes an increasingly unpleasant
and difficult operation.

For that reason, primarily the people at the Mayo Clinic.
But, but now also in many other institutions,
people are considering the idea of alcohol node ablation.
Again, kind of a a stop gut measure between doing nothing.
And just watching these lesions
and going back to surgery,

the ideal patient would have probably between one
and three lymph nodes, generally small.
Once they get much beyond 1.5
or two centimeters, they're probably a little too big
to start considering alcohol ablation.

The procedure is very much like a ultrasound
guided lymph node biopsy.
We use a 25 gauge needle.
We take a tuberculin, a very small syringe,
with one cc of 95% ethanol.
We instill a lot of local anesthesia into the skin
and the soft tissues.
This may be a rather uncomfortable examination.
We try to infiltrate the area
around the lymph nodes themselves,
to make them somewhat, numb.

We begin by advancing the needle to the deepest portion
of the node,
and inject as small amount of alcohol as possible,
a very, very tiny puff.
You look with the real time ultrasound
for an echogenic area at the tip of the needle, which
of course are the microbubbles that come out of the,
that are contained within the alcohol.

We then reposition the needle time
and time again until the entire lymph node has been treated
and we believe we've treated the entire lymph node.
Once the microbubbles outline the entirety of the node
and make it echogenic.

You can do more than one session.
If the nodes don't seem to be getting smaller
or if the TG has not gone down,
you can bring the patient back.
We try to limit the injections to very,
very small puffs
because it seems to be the extravasation
that causes the pain in these patients.

At this point,
and again, I have to thank the folks from the Mayo Clinic
for this, 'cause we've never really done one,
recurrence in the surgical beds are probably best avoided,
again, according to Bill OW and his group.

There is the possibility,
these are probably not really well-defined lymph nodes like
in the cer in the cervical lymph node chains.
And there is a probably higher likelihood
of extravasation.
And there is usually the presence of, there is the presence
of the recurrent laryngeal nerves so
that you may get hopefully transient
or even permanent paralysis
of the recurrent laryngeal nerve.

So we have not done, surgical bed recurrences,
although oftentimes these are small.
These would be really ideal lesions to treat,
but at this point we've really avoided them.

We then follow patients at three
and then six month intervals.
And again, if the lesion continues to grow,
a repeat ablation is possible.
Again, because this is such an indolent disease, we tend
to be very conservative about continuing to retreat
and retreat in these patients.

Success is somewhat difficult to determine.
Sometimes these lymph nodes will decrease somewhat.
They don't tend to actually just dry up and go away.

I'm not sure how useful changes in perfusion
by color might be.

The big deal here is of course looking
for a drop in thyroglobulin levels.
If the TG levels go down the, the serum TG levels go down,
that probably tells you quite, quite nicely,
that these patients actually have,
a successful treatment.

We have had a couple
of patients in whom we've treated them
where pet shows an absence
or decreasing activity after ablation.
Also another guide to probable, success
of, of our treatment.

Again, this is a metastatic node in a patient.
You can see the echogenic foci here within a typical
of the Sonomas calcifications.
The needle is advanced to the more posterior portion,
and here you can see the back half
of this lesion has now been injected.
And the echogenic microbubbles are present,
start at the back because if you start at the front,
it will obscure the whole node.

Here you can see that the entire node is now,
full
of these echogenic microbubbles telling us
that we've pretty much treated all parts of the lesion.

Conclusion

So, that's our, our story with,
thyroid cancer and surveillance.

As I said, imaging is an essential part
of the surveillance process along with TG levels.

It's an indolent disease.
And so I think conservative approach to this is,
is very, very important.

Guided biopsy and,
and now we have the possibility even
of therapeutic intervention.
So certainly imaging
and radiology is paying, playing an ever increasing role,
in this group of patients.