BTK Breast Standard
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[00:00:00] Hello everyone. Welcome to the new Behind the Knife miniseries on the operative standards of Cancer surgery. These are manuals that are developed through the American College of Surgeons Cancer Research Program, the operative standards for cancer surgery. Volumes one, two, and three offer concrete evidence-based recommendations on cancer surgery techniques critical to achieving optimal outcomes.

15 disease sites were covered in these three volumes and standards for additional disease sites are in progress. My name's Lexi Adams. I'm on the education committee for the Cancer Surgery Standards Program. We have launched this new series to help spread the word about these operative standards and to discuss each of their requirements, timeline and rationale.

Today we're discussing one of the operative standards on Sentinel Lymphadenectomy for breast cancer, more commonly known as axillary sentinel lymph node biopsy. To help with the discussion, I'm joined by my fellow committee members and breast surgical oncologists. Dr. Lauren Postal, wait from Emory University and Dr.

Chantal Rena from Loyola [00:01:00] University, as well as one of the contributors of the chapter, Dr. Susan Pries. She's a professor of surgery and vice chair for quality and safety, and director of the Rutgers Breast Center at University Hospital. She also served on the American College of Surgeons Board of Governors and the chair of the a CS Women in Surgery Committee and is a past president of the Association for Women's Surgeons.

It's an honor to have you here and it's fantastic to have such a panel of experts to discuss this important cancer surgery standard. Dr. Post await, would you mind, uh, beginning to discuss the goals of this podcast?

Sure. Today we'll be discussing the critical elements involved in Sentinel Lymphadenectomy for breast cancer, as described in the operative standards for cancer surgery volume one.

The overarching goal is to educate the surgical community on the key steps to axillary sentinel lymphadenectomy, or we might just call it lymph node biopsy. We hope, uh, this will be a thought provoking and practical, uh, discussion. Offering technical pearls to both [00:02:00] oncologic specialists and general surgeons alike.

The four critical elements up for discussion today are one, identification of all sentinel lymph nodes, two techniques for injecting local tracer or dye. Three, pre incision evaluation of drainage pattern and four node removal technique to limit seroma formation.

Perfect. Well, let's dive into it. Uh, Dr.

Reyna, do you want to start by discussing the first critical element, which is identification of all sentinel lymph nodes, starting with how do you define the sentinel lymph nodes?

I would love to, and thank you for having me on this podcast. I'm very excited to be here. So, sentinel lymph nodes in breast cancer are defined as the first straining lymph nodes on a direct pathway from the primary tumor.

So for most breast cancers, these sentinel nodes are located in the level one and level two of the ipsilateral axilla. And this usually falls somewhere between the pectoralis major and the latus [00:03:00] doci along the inferior hairline about a five centimeter space. The approach to the sentinel lymph node identification depends on whether the tracer is used or die is used, and there's even a few emerging technologies that we'll talk about a little bit as well.

But for this talk, I'm gonna focus more on the commonly used ones, the radiotracer and color dye, or a combination of these methods. In some cases we might even take into account some biopsy proving lymph nodes, but really for all cases as well, any nodes that feel abnormal during intraoperative palpation.

And in some cases, we'll also take into considered biopsy proven flip lymph nodes. We also need to remember that any lymph nodes that be abnormal during surgery are considered sentinel nodes. So when a radiotracer is used, a gamma prob is used to identify the hottest node. And once that node has been removed, an ex vivo or outside the body, highest [00:04:00] count, or a ten second count is obtained.

Any node that's within 10% of this highest count would be considered a sentinel lymph node, and it should be removed. So basically you keep hunting lymph nodes in the axla until the background of the axla is less than 10% of the hottest ex vivo count. And something we should be aware about is that when you remove the lymph node from the body, you should double check it because in vivo, a count can be higher than expected.

It can be falsely elevated due to scatter from the breast injection fight. Now let's switch over to the colored dye. And so when we use a colored dye for sentinel lymph node. The colored nodes and channels are identified in the ATE during blunt dissection by direct visualization. We see it. We see that color in all colored nodes or non-colored nodes at the end of a colored track are considered sentinel lymph nodes.

And I think this is something that I didn't appreciate for a long time. [00:05:00] So remember, even if the node isn't colored, but it has a colored track going up to it, it is a sentinel lim. Now if you use dual tracer or multiple tracers, then all the aforementioned rules apply all hot nodes within 10% of the hottest node.

All colored nodes on non-colored nodes at the end of the colored track are considered sentinel nodes. So some of these may be hot, some may be hot and colored, some may be just colored, some may be non-colored at the end of the track. But all of these are considered sentinal notes. And lastly, once you've removed your hot node, the colored node, the non-colored node at the end of a colored track, the axle should be palpated for any abnormal feeling node because any palpable concerning lymph node is also a sentinal node.

So on a side note, sometimes the clip nodes can be used in addition to tracer injections, to identify lymph nodes [00:06:00] that were biopsied and proven positive prior to surgery. And these clip nodes that 80% of the time will also be your sentinel nodes. It's important to retrieve these clip lymph nodes in order to have the most accurate axillary staging you can have.

Thank you. So to summarize, uh, identifying all sentinel nodes involves searching and removing nodes within account of 10% of the highest node when you're using radio tracer. Uh, also searching for and removing all color nodes and non-colored nodes at the end of a colored lymphatic channel. Wind, eyes used, removing all suspiciously palpable nodes and removing clip nodes.

If there are any clip nodes. So I understand the steps on how to do this, but Dr. Ies, as one of the original contributors to the chapter, can you comment on why this is recommended? Why is identifying all the sentinel nodes so important?

Well, thank you Lexi, and thank you for including me in the discussion [00:07:00] today.

Uh, it's critical to identify all of the sentinel nodes because that information is typically used for staging and to make additional multidisciplinary treatment decisions, and having accurate information to inform these decisions is key. In the N-S-A-P-B 32 study, for example, the median sentinel lymph node yield was two.

And in that study, as the lymph node yield went up, the false negative rates went down. Uh, just illustrating that all the, that identifying all of the nodes improve staging accuracy. And if you have just the one lymph node that can lead to a false negative rate. Of, uh, over 10%. That's based on a study that Dr.

Craig did back in 2012. That's referenced in the chapter and I think that that reflects some of the [00:08:00] original research that was done randomizing patients, uh, into sentinel lymph node alone, or sentinel lymph node plus axial dissection. And that's how we. The, um, false negative rate was derived. Now, some of that, that is a pretty high false negative rate, and it also may reflect the learning curve at the time when people were just starting to learn these techniques, but.

You know, it does give you a little bit of a quandary, uh, when you're in the operating room and you only really identify one node with either the blue or the hot dye, and sometimes there just really aren't a lot of other nodes palpable. If that's all there is, that's you really do have to stop. But if there's a chance to look around and find a second or third node, that's certainly going to be very helpful to the medical oncologist and the whole, [00:09:00] uh, multidisciplinary team.

Thank you for that insight. So now that we've heard how to identify all the sentinel nodes and why it's important to do so, uh, Dr. Postic, can you speak to the second critical element we're addressing today? The technique for injecting, localizing tracer or dye. I feel like I've seen a lot of different techniques through different RO rotations in residency.

And where exactly should we be injecting these dyes and tracers?

I'd be happy to talk about that. And, you know, you've seen a lot of these techniques because all of these techniques are, uh, are possible opportunities to identify nodes. Um, there are actually quite a few acceptable options for tracer or die injection, um, in the breast for fentanyl, lymph node biopsy.

Because the site of injection within the affected breast has not actually been shown to directly correspond to the ability or inability to appropriately identify sentinel nodes. In fact. In a systemic review comparing [00:10:00] seven different injection sites in the ipsilateral breast from intratumoral, intraparenchymal, peritumoral peri or sub alar subdermal, and combinations of these methods, the false negative rate of sentinel lymph node biopsy was similar across the board regardless of injection site.

So when we think about delivering quality care, there's no specific location of injection within the breast that's recommended over any other. However, surgeons should keep track of their lymph node yields from sentinel lymph node biopsy with a goal of removing an average of at least two sentinel nodes again.

We're not stopping it to and we're not taking nodes that aren't sentinel nodes to get to, but this is a quality metric just to ensure, um, that the preferred injection method and technique are actually working to identify all sentinel nodes as the median yield should be around two. [00:11:00] And so we should track ourselves and just make sure that what we're doing is working in our practice, but all of the sites of injection are acceptable.

So I'm glad to hear there actually are a lot of options for location of tracer injection. Uh, can you speak more specifically about your approach to actually injecting the radio tracer or the dye?

Yes, of course. I'll start with Radiotracer. The two most common tracers used are TECHNETIUM 99, labeled sulfur Colloid and Technetium 99 tep.

Usually a nuclear medicine department injects the tracer into one or multiple sites of the breast on the day of or the day before surgery. Surgeons can also inject this tracer intraoperatively if they've been approved by their facilities. The tracer radioactivity depends on the timing between the injection and the operation, as well as the age of the [00:12:00] radio tracer and how many half-lifes it's been through.

The most common colored dye for sentinel lymph node biopsy is ISO sohan blue. Typically one to five milliliters of dye is injected into the breast, which is then massaged for about two to five minutes to promote drainage into the lymph node basin. Notably, iso sohan blue, um, has a risk of 1%. Of severe allergic reaction, which can include anaphylaxis as an alternative with a lower risk of allergic reaction.

Methylene blue can also be used, however, methylene blue use does carry a risk of skin necrosis and a dilution of methylene blue in normal saline at a one to two ratio is commonly pursued.

Dr. Co. I know I mentioned earlier that there were other techniques, and I think you might have some experience with some emerging technologies in terms of sentinel lymph node identification.

Would you mind telling [00:13:00] us a little bit about your experience with that?

Yeah, certainly. Thank you, Dr. Rena. There is a newer technique that's based on, iron oxide nanoparticles. Uh, the trade name is Mag Trace and, uh, it, it's used with a system where it's basically a metal detector to find those, uh, the iron particles.

So it, it seems to be extremely useful, uh, especially when you're. I have a patient with DCIS that has enough disease that a mastectomy is going to be necessary. And for those patients, we've traditionally done a sentinel node biopsy, but as we all know, many times there is, doesn't turn out to be any invasive cancer.

And then the patient has had a sentinel node biopsy and potential for complications or morbidity. [00:14:00] Uh, that is really unnecessary. So by using this new technique, um, you can inject with the mag trace or the iron oxide, and that can be done even before surgery. But the the signal will last. For a month or even longer.

And so you can do the mastectomy alone, and then if the pathology comes back as no invasive disease, you're done. And if there is an invasive component or some occult invasion, then you can go back and do the sentinel node biopsy separately, and your node will already be labeled. Now, of course, this does require having.

The special probe that is essentially a metal detector made by the company and the tracer is not inexpensive, but I think it does offer a nice alternative

from your description. My [00:15:00] understanding is, is that it has the ability of having a probe and identifying with signal, but it also has a colored component to it, so it's almost a dual tracer in itself.

Correct. It has a brownish color to it, and so you'll be able to see it in the lymph node as well as picking it up with the signal.

Thank you for discussing all the different types of tracers, uh, that are available. Now the third critical element is the pre incision localization of the drainage pattern.

So Dr. Reyna and Dr. Uri, what, what are your preferred methods of localizing the sentinel node and how do you identify and approach those that might have extra axillary drainage?

Yeah, so I like calling it, let's find the hotspot. So what that means is that you do a transcutaneous localization to minimize the invasive approach to the axilla.

So [00:16:00] when I use radiotracer, I will find the hottest area by either using a radial pattern or even concentric circles, really trying to find where that hottest point is, and I'll mark that point on the skin. The reason we do that is so that we can have as minimal approach and minimal disruption to the underlying tissue.

So my preferred approach would be the technician. And um, I generally have the injection done the day before. Um. I use the, uh, probe. We do, uh, generally get lympho synography just to get an idea of that, that I did migrate and that get a idea of how many nodes are involved. However, that's not necessary and a lot of places don't do it, uh, especially if the surgeon is injecting in the pre-op area, which is done in a lot of institutions.

But that's just been my [00:17:00] practice. The setting that I work in, I think, um, there's a lot of perhaps unfounded fear about handling radioactive materials in the preop area. And I think it would be difficult to get the pre perioperative staff that I work with comfortable with that. So we do have it done in nuclear medicine, at least at this point.

In terms of finding the the node with the probe, uh, I always do a background count in the room, and then I do a. Preoperative count of the axilla and try to see exactly where that note is sitting. Uh, there usually are in level one or two as we've discussed, and they're usually right under the pec.

But then after I've done that, I make the incision and, go through the fascia and then start looking. And sometimes it will be in a slightly different spot than it seemed when you looked outside because the tissue does, [00:18:00] um, sort of move around as you continue the dissection. And, uh, I think even if.

The signal, uh, seems a little bit low before you get started. Once you get inside with the probe, usually it's not very difficult to find the hot node. And I, you can just adjust the sensitivity on the probe so that you have a better chance of finding it. In

the rare instance that you do have drainage to an internal mammary node, how do you approach those cases?

We generally do not recommend going after the internal, after those, um, nodes that are outside the axilla, there really hasn't been shown. There's no literature to show that that is worthwhile. If there's a node there, um, that is concerning, you can always treat that area with radioactivity.

That makes sense.

The, [00:19:00] the fourth and final element of the operative standards is the node removal technique that limits seroma formation. I have also seen many different approaches to try and prevent this, uh, Dr. Postal. Wait, do you have any preferred techniques?

I have to say I do not have a preferred technique, and frankly, I hate Seromas.

So I'd love to hear if anyone else has thoughts on this. But there's actually been no one method in the literature described that will definitively decrease seroma rates. So really it's up to every surgeon individually as to how to approach this. It's recommended that. Whatever works best for you, where you have found that your seroma rate is lowest, that is what is recommended and um, and so it's important to decrease seroma formation as seromas in the axilla.

Postoperatively can cause treatment delays [00:20:00] and infections, which can ultimately affect oncologic outcomes, but unfortunately there's no. Way in any study that's been shown to decrease these rates. I don't know if anybody else has any thoughts on that, but those are my 2 cents.

Well, first I agree with you on the, I hate Seromas.

They are just not fun to deal with sometimes, even though they're supposed to go away on their own. But I agree, you can't see some delay in care. And I have seen so many people, they do clips. I've seen ligatures, I've seen harmonics, I've seen bobi, and. Really, you're right. There's nothing that really has been shown to decrease serum inflammation at this time.

I, I agree with that. I don't think the operative technique really makes a difference, except of course, you know, just trying to teach the residents about gentle tissue handling and, um, you know, for a sentinel node biopsy, you really shouldn't see a lot of [00:21:00] seromas. It'd be more common if you did make extensive aary dissection.

And even then, you know, it shouldn't be that common. The other thing that I wanted to add is that the patient can also play a role in, uh, preventing seroma formation. I just always remind my patients to take it easy, not to overdo. No sports, no swimming, no heavy lifting. Most of the time if they follow those rules, they do not get a seroma.

Um, and if they do start to get some swelling, I have them elevate their arm. Rest and apply some ice. Generally that's enough. Very occasionally I find that I have to aspirate a seroma if it's really bothering somebody, but usually that's the end of it. A seroma in the axilla is much less common than say, a seroma after mastectomy or something like that.

Oh, great. This was a wonderful discussion to cover all of the elements of [00:22:00] our operative technique per sentinel lymph node, uh, biopsy. And we appreciate all of the expert, um, opinions from Dr. Coreys, Dr. And Dr. Reyna. Um, while this seems like a very common operation that we do, it's important that we do it correctly, and we found with the operative standards is that we can help improve outcomes by adhering to proper techniques.

And we're trying to improve the, uh, cancer operations that all of our patients are getting across the country.

Thank you. So I think one of the things as we consider these standards is that if we're gonna do something, we should do it right. And as we've talked about these four different elements, uh, critical elements that go along with the operative standards related to sentel lymph node biopsy for breast cancer, that's what we're talking about.

If we're gonna do it, we should do it right, [00:23:00] however. The question then comes up, should we do it? Should we be doing sentinel lymph node biopsies on everyone? And while that's somewhat outside the scope of the discussion today, I do think it's worth mentioning. I don't know if Dr. Poise or Dr. Rena, y'all wanna talk about any of the new data that's come out on that.

Oh, now Dr. Aso, what you're getting on my jam here. I'm very excited about minimizing axillary surgery. Um, and so, I mean, we have a lot of new emerging data coming out, the sound. So for pre, like for surgery upfront patients, we are talking about the sound trial, we're talking about guidelines like the Choosing Wisely guidelines.

We also have studies for the, you know, neoadjuvant setting. Right? So I think there's a lot going on, and I think that's a great question in which patients. Do we still perform sentinel lymph node, but as of right now, it is still a standard. We should still be offering it to our patients but I think that [00:24:00] we have a lot of things that are evolving going forward.

Very exciting times.

Yeah, I totally agree, uh, especially with the choosing Wisely guidelines from asco, uh, for women, uh, 70 and older with, um, er positive small tumors. Uh, I think it's very reasonable to follow those guidelines and omit the sentinel node and avoid any morbidity for those women. And as Dr.

Rena said, the sound trial. Um, and some of the new data, uh, derived from the I SPY trial really will lead us to being more selective in the future about who needs an axillary dissection, certainly, and even who needs a sentinel node biopsy.

So it has been a privilege and an honor to spend this time with all of my speakers today.

It's been wonderful hearing about our standards and hearing how people approach [00:25:00] things. So I really just wanna say thank you all for, for having us a part of this.

Thank you so much for including me. It's really been a great pleasure to talk with everyone today. And, um, these are some of our favorite topics.

We're so excited to bring the cancer surgery standards to the behind the knife, uh, audience. These standards apply to general surgeons everywhere, uh, trying to make cancer care best for our patients. Uh, so we hope you learn something today and stay tuned for the next, uh, podcast in our miniseries.