Thyroid Cancer Staging and Surveillance - HD

Introduction

Thank you, and thank you for inviting me,
I have no disclosure.

In the talk, we'll briefly review the issues
of differentiated thyroid cancer,
although they have already been addressed in the two
previous great talks that we had.
We'll talk a little bit about updating,
staging and management.
And then we'll spend most of the time,
talking about cervical lymph node assessment nomenclature
that we use ultrasound technique, the characteristic
of abnormal and abnormal cervical nodes.
What should a preoperative,
cervical ultrasound include in patients
with newly diagnosed,
thyroid cancer?
And what do we do after in the surveillance period?
And we'll conclude by a few words about a couple
of tips about FNA of suspicious lymph nodes.

Epidemiology of Thyroid Cancer

We already talked about,
maybe I'll skip over these slides quickly,
the rising incidents,
of, thyroid cancer,
and yet the, mortality has remained completely stable.
And this is because the vast majority of,
thyroid cancer, the well differentiated cancer,
and the majority of pape thyroid cancers.

While the survival
for pape thyroid cancer reaches 98% at 10 years,
this cancer still has high propensity
for nodular metastasis.
And in some series, at the time of initial diagnosis,
30
to almost 60%
of patients have cervical lymph node metastasis.
And it depends how you define cervical
or lymph node metastasis,
whether they are microscopic or macroscopic.
And the majority are in the central neck
level, six or seven.
And those, in fact, are associated with an increased risk
of the patient having lateral neck,
no nodal metastasis as well.

The question is, does
that have effect on long-term survival?
Perhaps there is a worse prognosis in older patients,
but certainly these do represent a risk factor
for local recurrence
or, later on, cervical node metastasis.

Goals of Therapy

The goals of therapy, as we recognize that,
most pe thyroid cancer, Indo disease, the goal
of therapy is really to improve disease-free survival
and reduce the risk of persistent
or recurrent disease by identifying nodal metastasis
with high resolution neck ultrasound, doing final aspiration
of suspicious lymph nodes to confirm that they're malignant.
And this will, influence a surgical management,
whether in addition, to the thyroidectomy,
the patient does need a cervical node dissection.

This allows a more accurate staging
and risk classification,
and hopefully, it minimizes treatment, really morbidity
and unnecessary therapy.
And really the trend now is to be,
have less aggressive treatment as we recognize that many
of these patients have Indo lung cancer.

A core issue is how to balance treatment associate
benefits with treatment associate harm.
And in the differentiated thyroid cancer,
that's not always an easy proposition.

Preoperative Imaging

The preoperative imaging, once a patient has a diagnosis
of differentiated thyroid cancer,
include a high resolution neck ultrasound to identified,
potential suspicious lymph nodes if they are identified
through an FNA to confirm that they indeed are malignant.
In some patients, particularly if there's a bulky,
thyroid mass
or bulky nodal disease, these patients, some
of them will have a neck CT or neck MR, with a contrast.
And in very selected cases in the rare patients
where we suspect that they have a very aggressive lesions
and they would have a PET CT
or a pan CT to look for distant metastasis,
this would be really the minority of patients.

Evolution of Management

Because the management
of differentiated thyroid cancer also has evolved,
while tumors that are larger than four centimeters,
or those who have extra thyroid extension
will undergo total thyroidectomy.
The, an new a TA guidelines from 2015, identified
that some patients are indeed candidate
for hemithyroidectomy patients have unilateral tumors, one
to four centimeter without any nodal metastasis
patients who are low risks.
And of course, there are the,
those patients were indeterminate
with indeterminate nodules if the,
gene testing is suspicious.

And then finally, we, I think we're starting
to recognize that there may be a role of survey
for surveillance of a PAB thyroid cancer
once soter less in selected cases, especially older patients
who have a lot of, other comorbidity.

In addition to that, the management
of a differentiated thyroid cancer is if there are
macroscopic nodal metastasis, do a cervical node dissection
that was geared to the area where there ares com,
the cervical compartment
that has these nodal metastasis diagnosed, consider,
radio iodine, ablation in high risk patients.
These patients,
after surgical have th TSH suppression with LT four
and surveillance at regular interval
to detect those patients will have a recurrence.

It's also important the, the endocrinologist
and the endocrine surgeons always,
identify high risk patients,
because this will have a higher mortality of can reach 30
to 40% in patients who have really high risk.

Risk Stratification

How do you know, the, what is the risk ratification?
Low risk patients, you consider the age
of diagnosis either over 16
and less than 55, used to be 45.
Now the new guideline says 55 primary tumor diameter less
than 1.5 centimeters and no evidence of capsule, invasion
or metastasis.
By contrast, the high risk patients are patients
who are going to be, less than 16
or above, 55 male larger tumors
with exter extra thyroid extension
or metastasis patient also who have a history
of neck radiation or patient who have a family history
of differentiated thyroid cancer.

Neck Anatomy

Having, with this background,
let's talk about, cervical, neck ultrasound.
And with, first I want to review the, anatomy
because we really have to, employ the, the language
that the surgeon use.

This is an excellent seminal paper by Al,
published in Niger in 2000,
who describes the neck compartment.

We talked first about the central neck compartment,
which will contain above the level of the higher bone,
level one A
and one B, which, superiorly there.
Mandible inferiorly the higher bone,
and there, there, there are one A
and one B separated by the anterior belly
of the di gastric muscle.

With respect to pary thyroid cancer, the vast majority
of metastasis that are going to occur are going
to occur in level six.
And this is, the borders
of this level is superiorly the thyroid bone inferiorly,
the sternal notch and laterally the medial margin
or the medial wall of the common cate artery
and medially the, the trachea.

The medial wall
of the common cardiac artery sep separate the central neck
compartment level six from level three and four.
And this is just a cynic clip in a patient
who has already had a thyroidectomy showing the, the,
the level six,
level seven is just basically the superior media sternum.
That's a lot diff more difficult to see with ultrasound.

The lateral compartment of the neck, contains level two A and two B.
These are, between the sga superiorly
and the heart bone inferiorly, and they are separated two A
and two B separated by the plane
through the spinal accessory muscle.
And the, the lateral margin
of level two B is the lateral board
of the sternal oid mastoid.

The vast majority of metastasis that occur
with pap thyroid cancer occur in level three and four,
and some in level five.
Level three is bordered superiorly
by the hyoid bone inferiorly by the area
of the crack cartilage medially
by the medial wall of the common cardiac artery.
And, and then the level four is basically
between the cricoid cartilage superiorly, the,
clavicle inferiorly, the medial wall
of the common car artery medially,
and the border of the sternal choroidal mastoid.

Level five, a
and five B are more posterior.
They are between the posterior border
of the steroidal mastoid
and the anterior border of the trape UUs muscle.
And the distinction between five A
and five B, again, is the level of the crico cartilage.

This is just again, a CIC clip.
In of the lateral level we go from level
three to level four.
And you can see here the landmark is really the
common carotid artery.

Ultrasound Protocol and Reporting

Ultrasound protocol and reporting is very important.
This is a tedious examination,
which really requires meticulous technique,
and there is definitely a learning curve.
I encourage all of you who do it to, to, to train your sonographers.
We had a training period with sonographer
where they do about 10 cases, which is, check
by a more senior sonographer
before they can be on their own.

When you read this study, it's really important to correlate
with lab abnormality.
Look at the whole picture. If the patient has had a
thyroidectomy already,
look also at the thyroid globulin level.
If, if you don't see anything
and the thyroid globulin level is normal,
then your, your scar free.
If, if however, the patient has an elevated thro globulin
level, go back and, double check
and rescanning by physician monitoring the study,
especially if there is any abnormality, I think is,
very, very important.

The other thing is we need
to really have a good communication
with a referring physician.
Use a standard reporting as Dr.
Tesla mentioned, and get feedback from your surgeons.
And believe me, if you don't, if you don't ask
for it, they'll give it to you anyway.

This is our scanning protocol.
And the only thing I wanna point out is
that we always look low in the supraclavicular,
the low level four region
with our sector curve in your transducer,
because occasionally you will pick up an abnormality you
don't see with a linear transducer.

We have a standardized report,
and that's very, easy to do these days,
and you just have the default is no suspicious nodes
and then you can just, fill in
where you see something.

The other important thing is to have a diagram
where we mark a frontal
and two lateral diagrams for left and right,
and we mark the nodes that are suspicious, only the nodes
that we feel are suspicious.
And this is integrated within the patient's medical record.

Ultrasound Characteristics of Normal and Suspicious Lymph Nodes

What are the ultrasound characteristics of, normal
and suspicious lymph nodes?

When we look at nodes, where you look at,
look at the size, but the size is really the least useful,
because small nodes,
less than eight millimeters can indeed be malignant.
However, a TA guidelines 2015 recommends FNA only
for suspicious lymph nodes that are eight millimeters, eight
to 10, eight or 10 millimeters or more.

Look at the shape, the long axis over the short axis,
the look for an echogenic hili look at the EQU texture,
an architecture of the node and the vascularity.

A benign nodes will have an oblong
or oval shape with a a long to short axis ratio over two.
They'll have an echogenic hilas,
they have a well-defined, kind
of branching vascularity coming in for the hili.
However, node that live nodes in level, two A
or two B can be a little bit rounder.
And the echogenic hili, if you have a very small nodes,
you may not be able to see it.

By contrast, malignant lymph nodes will be round
or lobulated or have irregular margins.
They have a deten, their long
to short axis will be less than two.
They'll have an absent or disrupted high less,
but they can also have very heterogeneous texture.
Sometimes hypo coic,
but also sometimes heterogeneously echogenic.
They can have punctate echogenic foci look
for cystic changes and look for irregular vessel.

This is one example here, in left level four.
Now this is, a little bit, careful.
Just a tip here is that, while we say
that nodes should have echogenic hila
and that's normal, sometimes these malignant nodes will have
echogenic architecture, it's just much more heterogeneous.
You get to, you have to get used to it
and ask your sonographer to do cynic clips.
Really helpful, to better analyze the lymph node.
And this was a malignant node in this patient
who had newly diagnosed papillary thyroid cancer.
Again, echogenic lde defined area.
In this case, the vascularity will be helpful.
You have dis fluoride, irregular peripheral vascularity,
so you know that this is not simply an echogenic hili.

Cystic changes have a high specificity of a hundred percent,
but low sensitivity.
If you see cystic area within the lymph nodes, no matter
what the size, that node is very, very suspicious.

Another suspicious feature is a presence of hyper coic foci.
Again, high specificity, but relatively lower sensitivity.
And this may represent either thermometer, calcifications,
sometimes just little OID dots.

Vascularity is also important.
As I said, normal lymph nodes will have a nice branching
regular vascularity coming in from branching in from the
central echogenic hili, this is a very irregular fluid peripheral vascularity,
and this was a left, level two node
that did not look that suspicious.
But if you look at the vascularity here,
it's very irregular.
This note was biopsied and proven to be metastatic.

The vascularity is really an adjunct or helpful feature.

Preoperative Assessment

When we are presented with a patient prior to diagnosis,
prior to sur surgery, prior to a thyroidectomy, what is our role?

We need to assess the primary tumor
and has already been described in the previous talks we need
to look for to see if there is extra thyroid or extension.
If there is substernal extension,
because of surgeon needs to know,
that it's gonna be a much more extensive surgery.

Look for,
suspicious nodules in the other gland in the rest
of the gland because especially if it's a small tumor,
the patient
and the surgeon may consider hemithyroidectomy.
You want to make sure that if they're going
to leave the other thyroid lobe there,
there is no nodule in there.

Look for cervical nodal metastasis.
And if the tumor's aggressive, you obviously want to look
for local invasion of vital structure.

In this case, I think, we should definitely look,
recommend a cervical, contrast
and hand neck C and look for distant metastasis.

This is really, this is an excellent
article from radiographic.
This is really what the surgeons expect from us.
And that's what we need to give them.

TNM Classification

This is just a TNM classification.
Basically, we look at size, we look at the presence
of nodal metastasis, and
and E one in the central neck, one being the lateral neck,
and distant metastasis,
which fortunately in this cancer are very uncommon.

Assessing Extra-Thyroid Extension

How do we assess extra extension?
It's often very minimal, only seen on history,
pathology and usual,
and that does probably not have adverse
prognostic, significance.

However, if there is gross extension outside the gland,
it'll obviously affect the surgery, make it more,
more difficult, affect the management.
This patient will go on to have radioactive iodine
and may affect the prognosis as well.

In this cancer, again, wide extension is uncommon.

What are the ultrasound findings to suggest?
Extra thyroid extension.
That was nicely, demonstrated in this paper
by the Stanford group.

If you have a tumor, just a budding the capsule,
they felt that it was sensitive, but not very specific.
A loss of the echogenic capsule
of the thyroid is probably the best productor.
And if when you look at contra bonding of the gland, if it's
absent, it has a high negative predictive value.
And also another thing they looked at is
vascularity beyond the capsule.

We have here a small hypo coic papillary thyroid cancer,
clearly, away from the capsule.
No thyroid extension, which was,
of course confirmed surgery.

This is a well subtle extra of mild, extra,
thyroid extension.
You can see here that the echogenic capsule
of the gland is interrupted by this tumor that is extending
outside the gland.
And the patient had minimal extra thyroid extension.

This patient who have of course,
a gross extra thyroid extension, the patient already used,
suspected right, because a patient presented was
symptomatic, she had vivo vocal car paralysis.
And there is extension, not only anterior knee strap muscle,
but you have to be concerned about is extension posteriorly
towards a trachea or even the paravertebral tissue.
And this patient, I think would, the surgeon will,
request a neck and hand ct.

Finally, a very large tumor like here,
you can't even see the borders.
This patient had a, very large tumor.
Then what they're gonna look for is invasion of the trachea,
abutment of the co carotid artery, the prevertebral,
fat and esophagus.
This, will require extensive surgery.
And unfortunately, this patient also had
metastasis in the abdomen.
This patient had this, a rare patient
that has a very aggressive tumor
with abdominal metastasis as well.

Detection of Cervical Metastasis

Detection of cervical metastasis is the next
and most important thing we do
because 30 to 50% of patients who are diagnosed
with PTC will have cervical,
nodal metastasis at presentation.

The majority will have micro metastasis,
but macro metastasis, will affect,
affect the prognosis adversely.

Palpation is not, a very good test.
But preoperative ultrasound detects suspicious lymph nodes
in about 20 to 30% of patients
with normal physical examination and
therefore will alter surgical management in these patients.
It also will allow selection of patient
who ultimately will need radioactive,
radioactive iodine treatment.

Ultrasound has an ex a very, good sensitivity
for, 76 to 80 per 85% for detection
of lateral compartment metastasis.

However, in the central neck,
when the thyroid is still in place, the sensitivity
of ultrasound is much less, to detect, metastasis in level six in these patients.

There is some controversy in the, surgical
and literature
regarding which patient should have central neck dissection.

This is just an example of how, this affect the management of, well,
if small 1.1 centimeter, a papillary thyroid cancer.
But this patient had a very tiny lymph node.
But you can see here that there are this little cystic area.
This lymph node, despite the small size was suspicious
and the patient did have a positive FNA,
the patient had not only a total thyroidectomy,
but also had a right lateral neck dissection.

Post-Thyroidectomy Surveillance

After total thyroidectomy, in the surveyance period,
what is the role of neck ultrasound?

After thyroidectomy, about nine to 30%
of patients will have recurrence of metastatic disease,
and most of them are loco regional.
They're in the neck majority,
74% have cervical node metastasis, 20%
or so have thyroid bed recurrence,
and some of them have, rare patients have recurrence in the trachea or the muscle.

Post thyroid anemia, neck ultrasound is recommended
by the A TA guidelines for follow up
because it has a high sensitivity in detecting very high
sensitive injecting recurrence
and metastasis, which can be as small as four
to five millimeters.

The follow up interval
that's generally recommended is six to 12 months
after thyroidectomy.
Don't do it earlier because there's too much inflammation
and edem mind the neck.
And then six to 12 months thereafter,
depending on the risk risk category of these patients,

we do the same protocol as we do preoperatively.
These patients also will have zero
C one thyroglobulin level if it's a
papillary thyroid cancer.
And with, an, and they also look for antithyroid globulin, antibodies
and consider ts simulation
before they measure the, thyroglobulin level.

The lateral neck protocol is the same as
what I just showed you,
but let's talk about the central neck compartment
after the thyroid has been removed.

Central Neck Compartment Post-Surgery

Normally after the thyroid has been removed,
basically you should have nothing
or a small amount of echogenic tissue
between the common carotid artery and the trachea.

What happens when you have a central compartment mass?
Of course you have to worry about either recurrence
or level six nodal metastasis,
but there are benign lesions that can be seen.
Some of these, masses that we see can be benign
and it's very common to see tiny nodules, three
to five millimeters.
And this really can be ignored, always say is
that they're tiny, they're too small to characterize, just,
follow up.
Next time, next, next time,
the when the patient comes back, you, you just look at them again.

In this study, of, 97 patients that had
central compartment lesions, they found that a majority
of them were actually benign.
63 outta 97 for benign and 34 were malignant.

The risk factors, the patients were more likely
to have a malignant lesion will have patients
who have larger primary tumors,
isic papillary thyroid cancer
or level signal metastasis at the time of initial diagnosis.

Here are two examples.
Small lesions, central compartment.
It's medial to the medial wall of the common quad artery,
somewhat irregular nodular
and lobulated hypo alion, another one
that has a small lesion,
probably no more than five millimeters,
but there is cystic component within it.
Both of them had recurrence.

This is a larger a mass, which would be,
more easier to diagnose with a,
vessel also enhancement
as you can see in level six on the CT scan.

But there are multiple mimics of this recurrence
or benign lesions
that can occur in the central neck after surgery.
Include residual thyroid tissue, which this patient has.
It's not always easy,
especially if the surgeon doesn't have a lot of experience
to make sure that you remove the entire thyroid.
You can have scar tissue, sutro, granuloma,
muscle fat necrosis, et cetera.

This, as I said, was confirmed
to be residual thyroid tissue.

Challenging Cases

Couple of challenging cases, just
as I said earlier in this patient,
which was post thyroidectomy, we did not see anything
with the linear transducer.
Always look with either the sector
or the curve line, transducer angle low
underneath the clavicle.
And this patient had a level four recurrence.

And then finally frustratingly for everybody,
the some lymph nodes that we don't know,
this is a large enough node that we, we see,
see a fatty hilum.
There's a little bit vascularity, you're not really sure.
We call them indeterminate, which
of course drive the patient and the surgeon crazy.
And biopsy was confirmed
to be a hyperplastic lymph node.

Fine-Needle Aspiration (FNA) of Suspicious Lymph Nodes

Just a couple of words to finish for ultrasound guided,
needle aspiration.

The role is to confirm an,
ultrasound suspicious lymph node preoperatively or
after, after surgery,
what we do is we do one suspicious node from compartments.
If it's, if there are multiple lymph nodes, for example,
in level three and four, we will do one of them.
But if the patient has, suspicious lymph nodes in, in,
in the level three or four,
but also in level six, we'll do one in the lateral neck
and one in, in, in the middle in,
in the central compartment, because this is different
surgery and I've done up to four compartment.
If the patient has suspicious lymphadenopathy everywhere,
our surgeon want surgical confirmation
before they go to surgery.
You can do up to or four compartments of the neck.

The challenges of course, special in the central neck is
that small sizes location near the internal jugular vein
or the carotid artery and then the other.

But we use 25
or 26 gauge needle, that at least is a saving grace.
But the other thing that can be frustrating is
that cystic nodes can yield a scan material.
And in this case, really what you need to do in addition
to just doing the FNA is make sure that we send,
for thyroid globulin concentration in the aspirate.

If it's a papillary thyroid cancer,
if it's a medullary thyroid cancer,
then you should send calcitonin level.

No cystic, you're not going to get a lot of cells.
But if you get a high level of thyroglobulin, and
the cutoff is about one nanogram per milliliter in this
paper, then if you have a higher level than that,
then you have to suspicious
that it is a malignant lymph node.

Conclusion

With that, the,
important thing is, a couple of things.
We need a multidisciplinary train.
We always go to a, thyroid nodule conference.
You really need to understand
what the surgeon needs from you
and communicate with them by a diagram,
diagram depicting abnormal note.
Sometimes in difficult cases we do a preoperative marking
or even go to the EO or for really difficult cases.

Thank you Ev, very much for your attention.