Local and Regional Staging of Breast Cancer Using Sonography - HD

Introduction to Local and Regional Staging of Breast Cancer with Ultrasound

This presentation is about the use of ultrasound to achieve the local and regional staging of patients with breast cancer.

The staging of breast cancer includes the local staging as well as the regional staging.

Local Staging of Newly Diagnosed Breast Cancer

Let's start with the local staging of newly diagnosed breast cancer.

Tumor Size

The first thing to check is the size of the tumor, which is going to determine the T of the TNM classification.

And of course, it's important to determine if the tumor is less than two centimeters in longest diameter, in which case it's gonna be a T one tumor or larger than that, in which case it will be a T two up to five centimeters or a T three even larger than five centimeters in most cases.

And assuming that the margins are well seen and the tumor is well demarcated from the surrounding tissues, it's gonna be relatively easy to measure the tumor.

This is an example of well-defined although irregular tumor that is easily measured, which measures 1.1 cm in longest diameter, that's another one, which is even smaller, but still very easy to measure.

And even this one, which is still in the range of one centimeter in diameter, is very easy to measure.

Now, when we deal with this type of tumor, which is poorly defined, then the measurements are more difficult to obtain.

And in that case, it's gonna be difficult to tell if the mass is less than two cm or greater than two cm in size.

This is another example of a mass, which is very difficult to measure, not to mention that one, which we can barely delineate.

One type of cancer, which is famous for being ill-defined is the invasive lobular cancer.

These are two examples of invasive lobular carcinomas, and these tumors appear typically as areas of shadowing due to their high content of fibrosis and limited cellularity.

So in those tumor cases, most of the time the best local staging will be achieved with MRI.

So that's for the tumor size.

Multifocality and Multicentricity

The second important point to address when we talk about the local staging of a tumor is is it one tumor or either more than one.

In other words, we have to rule out multifocality or multicentricity.

And that's actually the detection and diagnosis of any additional focus of cancer in the breast.

Now, the difference between multifocal and multicentric well is the following.

A multifocal cancer involves multiple foci in the same quadrant, and within a distance of three to five centimeters, depending on which school we listen to.

A multicentric tumor is a tumor, which involves multiple foci in different quadrants.

And the bottom line is that a multicentric tumor will not be amenable to breast conservation to a segmentectomy.

So this is an example of a bifocal breast cancer.

There is a known tumor marked with a T, but there was sonography detected a second nodule, which is marked with an n, at a distance of less than three cm.

So this is still treatable with breast conservation.

Another example of a bifocal breast cancer with two lesions.

Now, in this case, we have two lesions, which are separated by a distance of more than seven centimeters.

And more importantly on this extended field of view sonogram, which was taken transversely from the 11 o'clock to the two o'clock position.

Obviously these two lesions are located in two different quadrants.

So in that case there is no way that breast conservation can be achieved.

This is another example of a multicentric breast cancer.

Although initially the tumor was relatively limited to this 11 o'clock position.

However, while performing the whole breast examination, the technologist detected this minute lesion under the nipple.

And even though I was about to disregard this questionable lesion, I turned the power doppler on, and obviously there was significant hyper vascularity in this four millimeter lesion, which prompted an unguided fine needle aspiration, which confirmed the another focus of malignancy.

So this lesion under the nipple qualified for multicentricity and the breast conservation that was contemplated had to be canceled as far as the detection of additional foci of cancer.

There is no question that MRI is better than ultrasound, and I mean is more sensitive than ultrasound.

However, we also know that there is some limited specificity, and that the second look ultrasound is often needed to perform a biopsy to verify those lesions or additional foci detected by MRI.

To summarize about the local staging, we can compare with MRI, which is used in many institutions for that purpose, but it's not clear which patients should really have a preoperative staging MRI examination.

Other than those with an invasive lobular cancer.

And the cost effectiveness of preoperative staging MRI is still unknown.

And we should not forget the fact that only a limited number of patients with a newly diagnosed breast cancer will have access to MRI, whereas ultrasound is widely available.

Whereas ultrasound is more widely available.

Regional Staging: Evaluation of Lymphatic Spread

Let's move on to the regional staging.

The regional staging involves the evaluation of the lymphatic spread of breast cancer.

That's the n of the TNM, and it's the detection and diagnosis of a metastatic lymph node in the nodal basins that drain the breast.

The nodal basins that drain breast cancer include the axillary nodes, the infraclavicular nodes, the supraclavicular nodes, and also the internal mammary nodes, which represent the second most important drainage pathway for breast cancer.

Now, we should not forget about the fact that there is also the possibility of cross metastasis to the other side.

The importance of such cross metastasis is that a metastasis to a contralateral nodal basin is going to be considered as a distant metastasis.

In other words, a patient with a cross metastasis will be stage four.

So even though we have seen that MRI is better than ultrasound for the extent of disease in the breast, there is no question that ultrasound in experienced hands is better than MRI for the evaluation of the lymphatic spread, because you can evaluate rapidly more nodal basins than MRI can.

And more importantly, it's possible within minutes to confirm metastatic disease with an ultrasound guided fine needle aspiration of a suspicious node.

Technique of Examination

The technique of examination of the axilla is fairly simple, and it's done with the arm elevated.

The examination of the infraclavicular region requires that the arm be brought down.

And the examination of the internal mammary nodes is done by scanning along the edge of the sternum longitudinally and also transversely along each intercostal space.

Normal Ultrasound Anatomy of Lymph Nodes

Let's review the normal ultrasound anatomy of lymph nodes.

Let's begin with the axillary nodes.

The axillary nodes are usually replaced with fat, and they have this typical appearance of fat surrounded by fat with a very thin lining of residual cortex as pointed with the arrows.

So this is complete fat replacement is very typical of benign node.

This is another couple of examples of typically benign lymph nodes with a very very thin hypoechoic cortex, residual cortex, and most of the node being replaced with fat, which has the same echogenicity as the surrounding fat.

Now, on occasions, the central fat will show some decreased echogenicity, so that the appearance is similar to a target and with a hypoechoic peripheral rim, a more echogenic rim and a central hypoechoic component.

Again, this is typical of a benign lymph node.

It's important when evaluating the axilla to be able to tell if the lymph nodes are located at the level one, two, or three of the axilla, because the implications for the staging are quite different.

If the metastasis is in the level one or two or level three, The level two nodes are those that are located posterior to the pectoralis minor.

So the goal is to identify the pectoralis minor, which is easier to do on a transverse scan of the axilla.

And the margins of the pectoralis minor are the limits of the level two area.

This is transverse scan of the axilla showing the pectoralis major overlying the pectoralis minor, anterior to the subclavian vein.

As a rule, fat containing nodes are not demonstrated in the other nodal basins, which makes the situation relatively easy.

I mean, an abnormal node, especially hypoechoic, should be viewed as suspicious for metastatic disease.

So those fat containing nodes are rarely visualized in the infraclavicular and supraclavicular regions.

There are even rarer in the internal mammary nodal basin.

So this is an example of the normal anatomy of the internal mammary chains.

When you scan longitudinally along the edge of the sternum, you will see the cross sections of the costal cartilages, which are hypoechoic and which do not cast a strong shadow so that you can still see the pleural line underneath them.

And the only thing that we can really appreciate in the intercostal space are the internal mammary vessels, which we now call the internal thoracic vessels.

So this is a longitudinal scan of an intercostal space showing the internal thoracic artery.

Now on transverse scans both vessels will be visualized.

They can be seen on a gray scale with their characteristic pulsations.

Here we see the internal thoracic artery and the vein, which appears larger than the artery.

And of course, we can launch the color doppler and have the visualization of those vessels on color doppler.

But there is really nothing else around those vessels, but some fat between the lung and the ribs major.

Sonographic Appearances of Nodal Metastasis

So what is the ultrasound appearance or the appearances of nodal metastasis?

Well, first we need to have a disclaimer.

Sonography, like any other morphological imaging technique, cannot detect metastasis smaller than four or five millimeters in diameter.

Another point is that if we remember the physiology of the lymphatic drainage in the nodes, the lymph arrives through the afferent lymphatics at the periphery of the node and exits through the hilum.

So if we are looking for a site where the early metastatic deposit is going to be detected, it should be the periphery of the lymph node.

So the early lymph node metastasis will develop at the periphery of the node, and as the tumor grows, the entire lymph node eventually will be replaced with tumor.

What are the sonographic criteria for nodal metastasis?

Well, a number of indices have been tried and obviously do not work well, and those measurements are not used at least in our practice.

But the two criteria which are most important for me are one, the deformity of the node, which can be a focal bulge at the beginning, or a global deformity of the shape of the node, but that would be a later stage.

And also very important, the progressive replacement of the fat by markedly hypoechoic material.

The tumor is markedly hypoechoic in the node, and this is easy to detect, of course, if the deposit is large enough, and it's even easier to detect if the node was initially echogenic.

This is another example of a focal deposit relatively small, and this is probably in the range of one cm by three or four millimeter in thickness, which is markedly hypoechoic in an otherwise echogenic lymph node.

Now, as the metastasis grows, it's going to occupy larger and larger volume.

These are another two examples with one here, which has replaced half of the node.

This is another example of an otherwise totally echogenic node except for this metastasis.

And these are examples of small lymph nodes, which are totally replaced by tumor.

So please note how hypoechoic the tumor deposits are.

Microcalcifications in lymph node are virtually pathognomonic for metastatic disease, especially if the primary tumor contains such microcalcifications.

So this is an example of a myriad of microcalcifications in metastatic node in the axilla.

Infraclavicular Nodes

So let's move on to the infraclavicular nodes, which are the level three axillary nodes.

These nodes have an adverse prognostic significance since their presence means that the patient is stage three C.

This is an example of scan of the infraclavicular region.

It's a longitudinal scan.

We can see the shadow from the clavicle, and there is this lymph node, which is located right anterior to the subclavian vein.

Internal Mammary Nodes

The internal mammary nodes appear as hypoechoic masses that are located adjacent to the internal thoracic vessels, and they will appear as oval masses in longitudinal scans and rounded masses in transverse scans.

You remember that the normal lymph nodes are too small to be seen in that nodal basin, and that basically a hypoechoic mass in that region is a metastasis until proven otherwise.

So this is a scan of a normal internal mammary chain, showing nothing but the cartilages and the internal thoracic vessels.

But this is a longitudinal scan of an intercostal space showing hypoechoic mass, which has really nothing to do here, and which is again lymph node metastasis.

The internal mammary metastasis are frequently found lateral to the vessels, but they can be found between the vessels and even medial to the internal thoracic vessels.

This is an example of a transverse scan of an intercostal space showing a relatively large internal mammary metastasis lateral to the internal thoracic vein and artery.

This is the edge of the sternum.

Another example on the right side, showing a smaller lymph node metastasis adjacent lateral to the internal thoracic vessels, vein and artery.

And this is an example of a tiny lymph node metastasis, which is located actually between the internal thoracic artery and vein.

This is another transverse scan of an intercostal space with the edge of the sternum.

This is on the left side showing this internal mammary lymph node metastasis located medial to the internal thoracic vein and artery power doppler.

Arterial can demonstrate the high vascularity of internal mammary metastasis like in this case on the longitudinal scan, although the smaller the node and the more difficult to appreciate the hyper vascularity.

Supraclavicular and Low Jugular Nodes

And finally, let's mention the supraclavicular and even the low jugular nodes, which can be involved with metastatic breast cancer.

So the examination of the supraclavicular fossa is fairly easy, and if we see any of those hypoechoic masses in a patient, especially if they are already axillary nodes, then these should be considered as lymph node metastasis.

And if needed, might be verified just to refine the staging of the disease.

And this is the transverse scan.

This is the longitudinal scan showing one such metastatic node just above the clavicle.

The lymphatic spread can extend even higher up in the low jugular territory.

See an example of metastatic nodes in the low jugular territory.

Pitfalls in Nodal Evaluation

Some pitfalls. Well, lymph nodes can enlarge and be hypoechoic in case of benign reactive hyperplasia.

Most of the time they will still retain a central echogenic hilum.

This is a case of a fairly large and suspicious node, except that the patient has lupus and it's not infrequent to see enlarged nodes in the axilla.

In patients with lupus.

This is another case of a patient who has abnormal nodes in the right axilla.

The technologist drew the attention of the radiologist on that, and she looked at the contralateral axilla, which is a thing to do when there is an abnormal finding in one nodal basin.

And similar nodes were found in the left axilla.

The explanation in this case was that the patient was nursing, and this is another well known source of pitfall patients who are nursing have usually enlarged nodes in both axillae.

The message here is that at the least doubt it's good practice to examine the contralateral nodal basin.

Ultrasound-Guided Fine Needle Aspiration (FNA)

Let's move on to ultrasound guided FNA, because that's the most efficacious and also the most elegant way of confirming nodal metastasis in a patient with breast cancer.

Instrumentation and Technique

The instrumentation is very easy.

All we need is a 20 cc syringe, 20 gauge or 21 gauge fine needle, some alcohol, and a few gauzes.

The technique of needle insertion is the same for all nodes, and this is the technique that has been used for ultrasound guided FNA of virtually all masses in the body.

And this is something that has not changed in the past three decades.

This is an example of ultrasound guided FNA of an early nodal metastasis in an otherwise completely echogenic lymph node.

But at one pole of the node, there is this hypoechoic deposit, which is six or seven millimeters in size, and that was extensively sampled in real time.

And one pass was sufficient to yield very abundant material for cytopathologic examination.

This is another example of an early focal deposit at the periphery of an otherwise echogenic lymph node.

Again, the sampling is extremely accurate and takes no more than 20 or 30 seconds.

And one single pass with a 20 gauge needle is usually enough to obtain a sufficient material to confirm the metastatic nature of this deposit.

The ultrasound guided FNA of internal mammary lymph nodes can be a little bit trickier because space is very limited and there are some structures that we don't want to hit inadvertently, such as the internal thoracic vessels.

And of course, the lung.

This is diagram showing the technique of ultrasound guided FNA of an internal mammary lymph node metastasis.

Of course, this is done on a transverse scan since the approach is going to be from lateral to medial.

So this is how it goes.

The needle goes through the pectoralis muscle, which has been numbed before, and the tip of the needle, actually the bevel of the needle can be seen very clearly in this small six millimeter lymph node, which is located lateral to the internal thoracic artery and vein, which we can see proceeding right on top of the pleura.

And again, in this case, sufficient material was obtained and the diagnosis of metastatic disease was confirmed within 10 minutes.

So the analysis of lymph node metastasis is often obtained with a single pass within 10 minutes.

And for that reason the procedure is extremely well tolerated by the patient.

No local anesthesia is needed for the axilla or the supraclavicular region.

Of course, whenever we need to go through muscle, and that's the case for infraclavicular lymph nodes or internal mammary nodes, then local anesthesia is needed.

Complications and Advantages

The complications of ultrasound guided FNA of lymph nodes are the same as the generic complications of a FNA that's pain, bleeding, infection.

In the case of internal mammary nodes.

Of course, we should add the risk of pneumothorax to the list.

Among the advantages of fine needle aspiration is the fact that it is definitely less traumatic than core biopsy, and the risk of developing a hematoma is far less than with core biopsy.

This is an example of a huge hematoma that developed after a core biopsy of a lymph node performed at an outside facility.

And we had to drain a large amount of blood because of the excruciating pain suffered by the patient.

Impact on Patient Staging

Let's look at the impact on patient staging of the ultrasound examination of the nodal basins and the diagnosis of lymph node metastasis with ultrasound guided FNAs.

Well, when we find a lymph node metastasis in the axilla and we prove it with an ultrasound guided FNA, the stage of the patient is at least stage two.

The other benefit of proving a lymph node metastasis in the axilla in a patient with a newly diagnosed breast cancer is that it eliminates the need for sentinel node biopsy.

Finding a lymph node metastasis in the internal mammary chains means that the patient is at least stage three A.

If we find a combination of internal mammary metastasis and axillary lymph node metastasis, the patient is stage three C.

In the same manner.

If we find an infraclavicular lymph node or a supraclavicular lymph node, the patient is automatically stage three C regardless of the size of the primary tumor.

So again, to summarize, if we find a lymph node metastasis in the axilla, the patient is at least stage two.

If we find a lymph node in the internal mammary chains in the infraclavicular region or supraclavicular region, the patient is at least stage three.

So these are the important consequences of finding those lymph node metastasis in a patient with breast cancer.

This is a typical example.

This patient has triple negative breast cancer, but it's T one, even though it's a multicentric cancer, the axilla is negative.

So before the ultrasound the stage is T one and N zero, that is stage one A.

After the ultrasound of the lymph node basins, and the discovery of this internal mammary lymph node metastasis on this longitudinal scan.

And here is the transverse scan confirming the lymph node metastasis.

Now the patient is stage three A.

So that's a typical example of how ultrasound of the nodal basins can impact on the patient's staging.

When we do this regional staging with ultrasound, we have to do biopsies to confirm the abnormal findings.

Now, the primary tumor needs a core biopsy.

There is no question about that, but an ultrasound guided FNA is all we need to confirm any additional lesion in the rest of the breast to prove multifocal or multicentric disease.

And FNA is also sufficient to confirm a suspicious node, starting with the one that would impact the most on staging if it is positive.

Summary

So in summary, it is strongly recommended to include the regional nodal basins in the ultrasound examination of the breast in breast cancer patients and ultrasound with ultrasound guided FNA, the most cost effective technique for evaluating the lymphatic spread of a newly diagnosed breast cancer.

Incidental Findings

But wait, there is more, when we start looking away from the breast, we should be prepared for some interesting findings and a few possible incidentalomas.

So this is a couple of these are a few examples of some not so distant metastasis.

This is an example of a metastasis to the insertion of the pectoralis major to the sternum.

This is an example of metastasis to the sternum.

In fact, we were surprised to see that we could see through the sternum on this longitudinal scan because the sternum was totally replaced with metastasis.

This is an example of a lung metastasis, and this is an example of a metastasis to the thyroid from breast cancer.

Thank you very much for your attention.