Dr. Merrick Ross provides an overview of the indications and logistics involved with sentinel lymph node biopsy as it relates to diagnosis and management of melanoma.
All right, so welcome back everybody to the afternoon session. Our next speaker is dr Merrick ross. Dr Ross is a longtime friend and colleague friend of this course, Going back some 25 years plus and he's going to talk to us now about the sentinel node evaluation. Dr Ross is a professor at M. D. Anderson and chair of the melanoma unit. Take it away Merrick. Okay, can everyone hear me terry? Can you hear me? Yep. Alright, great. I'm gonna close this down well. Thanks terry and you for the invitation. I always enjoy participating in this meeting and everyone would have expected we'd have to do it virtually. I miss coming to SAN Diego but I would say that the organizers did a great job with this considering the complexity. I wanna give a shout out to scott Clelland who did a masterful job I think um everyone did great and I love my gift of I love my blue snowball as the as a gift. So that's great. Talk about a sentinel node biopsy specifically its impact on the management of stage 123 melanoma but also expanded to some of the other higher risk cutaneous malignancies. That's that was so that was my disclosure. So if we look at the new melanoma landscape a lot really happened that are that are tremendous in terms of melanoma in terms of follow up and new treatment advances and you can see them listed their new systemic therapies for stage four disease. Anti Pd one and the Wrath Mac and the edge of and setting novel intra regional therapies that will talk about tomorrow and then um integration of sentinel lymph node biopsy has really been an important advance considering at least 85% of newly diagnosed patients presented with currently localized disease. And I'll explain to you how sentinel lymph node biopsy has established a new Stage one and two disease, also a new stage three disease and have improved disease outcomes as well. So the topics that we'll talk about is an update related to a prognostic implications disease specific outcomes and who are the candidates completion lymph node dissection issues that has emerged over time and also its impact on the edge of an edge of in therapy decision making the relevant questions are why do we perform sense unload biopsies, which outcomes are improved? What are the techniques and the morbidity ease and who are the appropriate candidates? So the stage one and two patient population again is the most common patient that we see with newly diagnosed melanoma. With the components of treatment including a lot of excision with margins appropriate for thickness. And the question is what to do with the regional lymph nodes has been an ongoing controversy. It's important to recognize the importance of lymph node involvement in melanoma patients. Historically the harsh reality is that regional lymph nodes are the most common sight of first recurrence after treating the primary site with a wide excision And when those patients develop clinical modal disease. Despite a therapeutic lymph node dissection. There's at least a 50% chance for a distant relapse And a 15-50% chance for in basement failure after an appropriate section. So from a surgical perspective, these outcomes are really not really not acceptable and need to be improved. So one of the purposes of evaluating the technology of symptoms biopsy was to address these. This this harsh reality of patients who develop regional lymph node disease. And this is a little bit of a cartoon of the lymphatic drainage pattern from different um different sites of primary melanoma that that we can actually see. And the description of the lymphatic drainage patterns and medical melanoma cells metastasized at the microscopic level to regional lymph nodes and the first draining lymph nodes are called the sentinel lymph nodes. And they're identified by injections of either regular label collagen or blue dies. That traveled to the lymph node basins. We use Olympus Integra fee. That's shown here to identify the lymph node basins at risk. And you can see in this patient the closest nodal basin is not necessarily the basin at risk in the head and neck region. We have advanced imaging studies that fuse a rapid sequence ct scan with the nuclear medicine scan. This is called the spec C. T lymphocyte photography that has good an atomic correlates to where we would find the central now in the operating room. We inject the site with blue dye. The gamma pro wasn't used to localize the sentinel activity after the radio radio colloids injected and you can see very nice blue channels coursing to an obvious blue no, this is an incision in the groin. And if there is disease, hopefully the pathologist will find it here in the sub capsule, their sinus as a small by small focus of disease. So focus just a just a a zoomed picture of a central, if not being harvested from a small incision. The original published data That established this as a very accurate technique. Is that pretty much using the do modality of blue dye injections and radio Kabul Ka Lloyd that the identification rate is essentially 100%. It's accuracy in terms of false negative rate. So we established this by first finding the sentinel node. Originally doing no distractions at the same time. So we can compare the incidence of disease and the sentinel node versus the non sentinel nodes. And that false negative rate was less than 5%. So sentinel node negative patients never underwent. Never underwent completion. No deceptions because The risk of those having additional disease was essentially zero Or less than 5%. For sure. So less than 3% will develop nodal disease. And central no negative patients. The other important thing about the central note is that we give the pathologist a small amount of number of nodes so they can really carefully examine that knows no note. In a practical way to really identify the truly no negative patient population. So the goals in performing central node biopsy was to improve the disease outcome for the note positive patients in terms of survival, regional disease control and also limit the surgical morbidity. And we think the hypothesis was that if we prevented the development of a clinical nodal involvement, we would improve outcomes for the patients. We'll also give us an opportunity have a minimally invasive approach to lymph node staging. So let's talk about staging. So this is the most recent AJ CC version eight uh survival rates for stage one into patient population. So these are the clinically no negative patients. But now in the Version eight, the vast majority of these patients had sent on a lift node biopsies. So there these are the truly no negative patient population, which is why their outcomes are so good. But you can see there's still a fair bit of prognostic head originate e across the different stage groupings, but certainly compared to previous, um, a JCC staging criteria much improved. So the sixth edition, where the vast where the vast majority of patients did actually not have to not have sentinel lymph node biopsy only a fraction did you can see that the improvement across the stage is very significant. Look at the to see patients, these are thick melanomas that are ulcerated With clinical staging. The outcome was 45% of five years. But look at the 8th edition is 82% where the essentially all the patients were had central lift mode stages and therefore were no with no negative. So this is what I would consider to be the new stage in one stage one and two patient population that have significantly better outcomes than before. Because we've removed the early stage three patients into the next category. And this is a universal read analysis of sentinel if no negative versus central if not positive overall. And if you look at multi varied analysis and uh of the important clinical pathologic factors something lymph node status as the most important prognostic factor that we found you also. We just had a discussion about gene expression profiling and we'll talk about that a little bit later in the talk um Several large single institutions of multi center databases provided consistent findings for this. So it looked like the concept of preventing microscopic disease from becoming macroscopic disease was an important biologic event at least. That's a hypothesis. And we'll look at the disease outcome in preventing this progression from microscopic to macroscopic. This was evaluated in the M. S. L. T. One trial which is the multi center selective link that neck to me trial one which randomized patients with melanoma is thicker than one millimeter too wide Excision only versus wide Excision plus sentinel lymph node biopsy. And the original comparison was to look at the group overall and then we're also able to look at the cold positive patients versus the patients who underwent wide excision and then develop clinical recurrences within the noto basin. So comparing the note positive to note positive fractions. If you look at projected estimates of survival benefit based on previous trial observations. The World Health Organization looked at patients who had elective lymph node dissection and found that 20% survival advantage in the patients who were found they have microscopic no disease as opposed to patients who develop clinical nodal involvement. Another german multi center trial head started 15% benefit in a similar group. So assuming somewhere between 15 and 20% assuming of incidents of central node involvement or nodal disease involvement of 20% for the patient population you would expect an overall survival benefit of somewhere between three and 43 and 4%. Well, this particular trial is certainly not um powered to look at overall survival with the event rate that small. But but it's not a surprise actually that if you look at the 10 year overall survival, the central if not positive central if node biopsy patients had a better outcome than than than observed patients who develop who just had who just had wide excision only. But of course there's a lot of note, there's a lot of no negative patients in this group as well. again it's somewhere around 3-4%, which is what you would predict. But if you look at The difference in node positivity rate. So the sense of lifted by see patients only had a number of nodes involved at 1.6, the watch and wait group at 3.4 and therefore the number of the percentage of patients with advanced nodal disease. In the wider excision only group was significantly higher. And that would translate into patients who had very small disease progressing to very significant disease as is having an impact on outcome. So if you look at the sentinel lymph node positive patients versus the patients who develop clinical nodal involvement, the difference in outcome is 20%. So that that represents a significant improvement and outcome just by removing microscopic disease. It's also important to recognize that in this trial, the standard of care was to do a completion lifting of the section that after a positive central notes. So in this trial, all the patients with a positive sentinel node underwear, a completion lymph node dissection. So now we have like a new a new stage three disease. This is what we used to see gross nodal disease or even this patient doesn't really have a lot of lymph node involvement. Although the entire note is replaced by tumor. You can see the heterogeneity of different clones of cells. A male and arctic, partially. No. And now they can vary knowing that it as opposed to microscopic disease that is seen here both in the capsule or scientists on the intermediary portion, all in the sub capsule or just just a small cluster of immediate history, chemistry, positive positive disease. So this is what I would consider to be the new Stage three patient population. And the vast majority of patients that we see now with Stage three have this relatively early nodal involvement. So that's a good thing. So this is the new A. J. C. C. Staging criteria for the eighth edition. Now we have four stages instead of three. And then if you compare this to the seventh edition, you can see how well the three A. And three B's do compared to previously because these are patients with early microscopic disease and also relatively thin to us because the new staging system for stage three also includes some of the tumor factors that are important like tumor thickness and ulceration. So it's very important to recognize that the three A and three B's are influenced by other factors than just lift non involvement. So we just talked about survival outcomes that talk about regional disease control and as surgeons, we regional disease control is very important just like for dermatologists order biologic surges. Local disease control is important as well. So if we look at regional disease control within the treated lift node basin. So this is a constellation of several retrospective series. Looking at recurrence within a notable basin after complete therapeutic node dissection for patients that have clinical lymph node disease With a weighted average of around 21% recurrence within the basin. And there's actually higher risk groups with extra capsule extensions, the cervical location or more than four positive, knows where the recurrence in the Nodal basin that's already treated is actually 30-50%. that's unacceptable from a from a from a from a surgical perspective, I would I would suggest if you look at patients who undergo a completion dissection from microscopic Central Note positive disease. The recurrence in the noto basin is actually less than 5%. It's a very well tolerated procedure in terms of sentinel lymph node biopsy, this is the total complications and the comparing it to sentinel lymph node biopsy versus a formal if node dissection certainly much better tolerated. And even if you look at morbidity of patients who undergo a completion node dissection from microscopic disease compared to patients wanted to go a therapeutic dissection for palpable disease. That the symptomatic lymphedema rate is higher when there's macroscopic disease, the hospital stay is also shorter for the patients who had completion deceptions for central retinal positive disease. So even at the level of a completion dissection of morbidity is less where we're treating the patient with microscopic disease. Uh the central biopsy procedure is truly a multidisciplinary component that involves three preoperative lymphocytes. Integra fee for patients with ambiguous drainage sites like the trunk and head and neck region. The surgical approach requires a very dedicated approach by the surgeon and then there's the very sensitive pathologic evaluation that includes serial sections and immuno stains in the central note. Now, if you look at candidates for central lymph node biopsy, the kind of consensus recommendation is to consider doing a central node biopsy when the predicted risk of central lifton involvement is somewhere around 5 to 8% and that falls somewhere between the stage one a one B patient population. And you can see the incidents of a positive sentinel node increases literally with increasing stage within the stage one and two patient population. As I mentioned that the consensus threshold is 5 to 8% and that's also part of the NCC and guidelines which we'll talk about here in a second. So from the NCC. N perspective, micro staging of all melanomas are the primary tumor is certainly an important part of of staging pathologic normal staging is recommended for the stage one B through to see. And you know that the new one B category is is greater than 0.8 millimeters. And if there is at least one adverse prognostic feature, if it's less than 0.81 would consider doing a sentinel lymph node biopsy as well. And these were consistent with both the sso and the esco and the esco consensus guidelines are recommended with the threshold of 0.8 millimeters and thicker and consider it for melanomas lesson that with at least one adverse feature that brings up the issue about some of the rare varieties of melanoma, The desmond plastic melanomas being either pure versus mixed and these two have different biology's and that's related to how carefully the pathologist actually examines the primary tumor. If we can determine that this is a pure dismal plastic melanoma. The risk for sentinel lymph node involvement is extraordinarily low. As a matter of fact, even though the pure Desmond plastic melanomas are relatively thick but they're almost never ulcerated and they almost never have a positive central note. However, the mixed variety that has different that has both epithelial component as well as a Desmond plastic component. They seem to behave with the same biology as the as the rest of the cutaneous melanoma. So we generally do not offer central if not bob's he's for patients with pure desmond plastic melanomas regardless of their thickness. So let's look at some of the sentinel lymph node biopsy trial results as a summary and see if the goals are achieved. It is a minimally invasive approach to life, not staging based on historical information from for many years. The central if not status is amongst the strongest independent predictor of outcome. It improves the disease outcome for the cult noid positive patients in terms of survival, regional regional disease based in control and also limits the surgical morbidity. And again, we think that the hypothesis of preventing the development of clinical nodal involvement is correct, then if we treat to the disease. When we know that it's microscopic, our outcomes are better. So this is something where we can call a proof of concept that identifying and treating lymph node disease early improves outcome. We also have to ask the question, do patients really need a completion dissection to derive benefit? Considering morbidity is also an important goal. Minimizing morbidity is an important goal as well as retreating all patients with melanoma. Can we further limit the surgical morbidity without compromising the ecological outcomes that we just talked about. So the goals of treating patients with regional diseases to accomplish regional disease control, uh cure the patients that we can cure and also provide important staging because the more lymph nodes that are involved the worst the overall prognosis. So surgeons are pretty traditional overall and it's hard to make them change their mind. But fortunately many surgeons and most surgeons now believe in evidence. Um as opposed to our recent um um presidential administration, we actually surgeons actually believe in evidence and go by evidence, but so we can hopefully teach new dogs. We can treat hopefully teach old dogs new tricks with new evidence. So, trying to reduce the morbidity of all of our surgical approaches, There's been a lot of interest in trying to reduce the number of completion, no deceptions. It's important to remember that only patients with non sentinel lymph node involvement. So disease beyond the sentinel can actually derive benefit From a completion lifting of the section. And in reality this only represents about 10-20% of the sentinel lymph node positive patients actually have additional non sentinel lymph node involvement. So it's important to answer the ask and answer the question what is the fractional benefit of completion lymph node dissection above what is achieved by just removing the involved central lift notes? Because in reality the vast majority of patients with a positive sentinel node have disease limited to those central notes. There have been two prospective randomized phase three trials of completion node dissection versus observation of the nodal basin after a positive sentinel node with ultrasound surveillance. These two trials with a dick I guess LT performed in Germany and in north America and in Australia. The SLT to trial, which is a follow up from the SLT one. This is the design of the youngest LT to travel which is essentially identical to the deck I trial. Uh This trial has many more patients than the decoy trial. So it has more power but the ultimate ultimate designs are the same and the outcomes are virtually identical. What I will show you in the M. S. Lt to trial that in the patients onto an observation Had worse outcomes in terms of Nodal failure. The 25% of the patients develop normal recurrence after a positive central note versus the patients who underwent a completion notice section where the incidence of finding additional positive note is actually only 11%. But if you look at overall survival, so this improvement in regional disease control did not translate into an overall survival advantage for the patients. And you can see that here that these these survival groups are essentially overlapping. So while there is improved regional disease control, which is important, this does not translate into an overall survival advantage and additional the other thing that we identified however, that additional positive note. So nonsensical if not environment is the strongest predictor of overall survival in a multi varied analysis. So that's important staging information. If it's important to actually get that information, how here's the results of the deke I guess salty trials I wouldn't say stratify because it's because they weren't stratified. This is a retrospective analysis of burden of disease and the sentinel node of less than or equal to one millimeter versus greater than one millimeter. But the regardless of the burden of disease in the central node, it didn't look like there was an improved outcome with completion node dissection versus just just a surveillance with ultrasound, I will point out that this is confirmation of the concept that additional positive nodes is important that if you look at the total number of nodes positive and look at sentinel versus non sentinel. The patients that had non sentinel lymph node involvement had worse outcomes compared to patients that had disease only in the central notes. So if the two central lift no, it's positive versus patients who had a disease in the central node and nonsensical. No the sun that the non central no patients did worse. So even though they had the same number of lymph nodes suggesting that this is a different biology. Once the once the disease progresses from nonsense from sentinel to non sentinel the outcomes are worse. So the reality is that completion lymph node dissection for something left positive diseases. Really that practice is really an extrapolation from treating patients with clinical nodal involvement. The results of the N. S. L. T. One trial supported continued use of C. L. And D. Because that's what they had in the trial. But the dick I guess O. T. And the M. S. L. T. To trial show improved improved staging improved disease regional improved regional disease control but no longer no overall survival benefit and also increased mobility with the completion lymph node dissection. Of course the morbidity issues are important but in reality most of the morbidity related to completion. If not this section is really in the groin. That nexus sections are extremely well tolerated. Axillary dissection is also the risk for lymphedema in the arm is very low. Most of the morbidity related to completion dissection is related to the groin where the lymphedema rate is high and the complication rate is relatively high. So the N. C. C. N. Guidelines. The most recent actually support discussing completion lifting of the section kind of selectively but certainly would support observation in the vast majority of patients as long as they can be surveyed undergoing surveillance carefully and also had access to to to to the ultrasound for part of their surveillance mechanisms. Now let's move on to the very important landmark events that occurred in 2018 in 2019. It's important to consider these events and incorporate this these events into the, into the knowledge that we get related to finding a positive central note. The FDA approved the agreement anti PD one for all no positive patients with the primary endpoint being disease free survival. And this is based on the checkmate 238 trial which you're going to hear about later and this is the ip aluminum at versus novel a mob trial with a hazard racial in favor of the volume at 0.65. The keynote go four or five which was placebo vs. Anti pd one of the hazard racial. 0.57. Important to recognize that in these trials completion if node dissection was mandated for the patients with positive nodes. Even for even for the central node positive patients, the FDA approved uh achievement abravanel and traumatic for all not positive patients that were be raft positive. Um Again, primary endpoint disease free survival hazard racial 0.47. This was a double placebo trial. Again, completion lifting of this section was mandated and also the A. J. C C. Version eight was published Actually after these trials were completed. So the staging criteria used in these trials. Version seven rather than version eight. And as we mentioned before, this is a significant change in the stage three patient population. So these are the clinical decision making questions. What is the risk of disease failure in a JCC Virgin eight? What's the risk of having additional non sentinel lymph node involvement? Which would be important for for distant failure, risk of nonsensical different environment. Again, there's also a predictor of notO failure and also and also informs prognosis. So does the mission of a completion dissection lead to loss of regional control. Not likely how effective is edge of in therapy and treating microscopic nodal disease. And I'll tell you we don't have that answer yet. And well, completion lymph node dissection to delay the initiation of adjuvant therapy and I think it might. So losing regional disease control is really not an issue, particularly if we're going to survey patients very carefully. We would identify clinical disease early with ultrasound recurrence in the nodal basin after central lymph node biopsy is not the same as notO basin failure recurrence after a therapeutic notice section. So these patients have a different biology and we'll be able to disease control probably relatively in almost all the patients. But it's important to look at the predictors of a finding additional positive notes. And this is a nice working model that included factors weighted factors identified in a multi varied analysis of patients who underwent completion node dissection for a positive central note, it's interesting to note that the three independent predictors worth tumor thickness, how much disease was in the center load and how many lymph nodes where harmony centre Muslims were harvested In the lower the lower risk patients with the score 0-2 represents at least half the patients and their risk of additional positive notes is actually less than 4%. So you could pretty much rural out the need for completion node dissection and half of the patients. And this group of patients has the highest risk of total failure but also has the highest risk of developing distant disease as well. And then we have this intermediate group that represents somewhere around 30-40% of the patients with the risk of nodal involvement or risk of additional positive nodes is actually higher than the risk of distant disease. Where you might consider doing a completion node dissection. So the benefits of the completion notice section. A regional disease control only for patients with additional positive nodes. Um useful additional staging and prognostic information. Maybe the risks are long term and short term mobility of the procedure. Worse would be lymphedema and surgical complications might delay in starting edge of in therapy. So what about the efficacy of systemic therapy in preventing or treating microscopic disease? This is really a data free zone because as I mentioned, the immunotherapy and targeted therapy trials mandated completion lymph node dissection for these patients. But if we extrapolate the hazard ratios for for distant failure To the regional lymph node basin somewhere between 40 and 50%. Based on the checkmate 238 and keynote for 5054. We would suggest that we could reduce the risk of nodal failure by 50%. If if you can if you can extrapolate that over time will be able to see if that really berries out to be true that if we can actually half the half the risk of the patients developing clinical nodal disease after after a positive central note and observation. Uh So in summary select to lift the biopsy. Not only is an important staging to about likely therapeutic for the majority of the central, difficult positive patients because most of these patients have disease limited to the central node completely. No, this section provides excellent regional disease control for some but morbidity for many the completion lymph node dissection trials have to be practiced changing when we can no longer routinely recommend this procedure to these patients. But a selective use I think I think seems rational when the nonsensical lifting involvement could help in the decision to offer a gene therapy will get to that in a minute and when the risk of regional disease is greater than the risk of distant disease. And we would lower the threshold for the head and neck patients because these patients were underrepresented in all the all the surgical trials. So let's talk a few minutes about edge of in therapy and you're going to hear much more about this later. But the basic principles is that the edge of in therapy actually means the treatment of presumed presence of micro micro metastatic disease after reception of all clinical disease. So it prevents can prevent regional distant relapse. The relevant biomarkers are prognostic, which defines risk for relapse and the predictive markers are predicting predicting response to a specific therapy like to be wrapped mutated patients would predict response to targeted therapy. The efficacy is what we use to really what the FDA bases their their approvals on. That's really based on the hazard racial and clinical trials. The relative improvement and relapse free and overall survival. So we also have to look at the risk benefit ratio of adjuvant systemic therapy. The adverse events targeted therapy actually is more toxic than immunotherapy in terms of discontinuation of therapy. But the immune related events are less frequent but they're longer lasting and more serious and potentially life changing. And then we have to look at the risk for relapse as well. So the benefits will be improved disease free survival. We're all waiting for the overall survival and the absolute benefit for an individual patient is dependent on risk. So the higher the risk for relapse, the more the benefit overall again. So let's go back to our A. J. C. C. Staging criteria and look at the three A. And three B. And three C patients. You can see it's a relatively heterogeneous group of patients across the stage three patient population. And this has significant implications for patient counseling management and contemporary Edgemont clinical trial design. So if you if you let's just look at some some potential theoretical advantages. So the the the red group these patients die despite treatment. The green group shows benefits from treatment over the lower line there. And you can see that the black space all below those patients survived but cannot be identified yet. So those are the patients that get over treated. The problem is that how do you define what the baseline risk should be before offering uh a gene therapy the patients? And that's really the art of of of of the edge of in therapy. So how do we define? How do we find these patients who cannot be who cannot benefit from therapy? And how do we find the ones who can benefit from therapy? So the factors that we have the stage three patients, number of positive nodes. How much diseases in the central node? If there's nonsensical note involvement. Is there actually capsule their extension. Satellite and transit disease, tumor thickness and ulceration are now important for the three A. And three B patients. And what about gene expression profiling? What about gene expression profiling for the three A. And three B. Can this help us as well. And what about for the stage one and two patients to clinically localized thickness ulceration. My tonic create central node status and also gene expression profiling. So we'll talk. I know you had a long discussion this afternoon earlier so I don't want to I don't want to repeat much of the data, but I will show you some additional data disease. You had a long discussion about the I saw most of it but not all of it. Decision dX melanoma. You know, that's a class one versus class too. And then there's a one A one B into A to B. And then there's mela gen X, which is 11 gene RT PcR that identifies low risk versus high risk. This is the original validation training and validation said looks amazing, right? Like how can you not look at this and say this is fantastic data and it is fantastic detail and it is, is fantastic. But there's relevant questions we need the devils are in the detail. We need to know what the frequency distribution is of across stage and what the prognosis of class across stages as well because it may not be true. That Class one or class two means the same thing across the stage. So, if you look at this is a Paper that was published in 2018, which I don't think was shown in the original in the previous discussion. This is John Jonathan Zegers paper of 523 patients. You can see class one versus class too. And you can see that there's more class one patients than class two overall. And that shows across the different stages. But if you look at the three A the class ones don't do so great. They do better than the class, They do better than the class to patients. But there's still a large fraction of patients that do fine. But there's also a significant number of patients that don't do so well. And the other thing I want to draw your attention to when you're making decisions about omitting central node biopsy in patients that are class one for the elderly patient population, 50% of the 38 patients Have class have class one, Class 1 DX and 50% of clash too. So a significant number of patients with positive central nodes Actually our Class one. And so if you look at relapse free survival and distant metastatic disease free survival, this is the this is the class one versus class too. And in three B and three C, they all don't do very well regardless of the class. So it's important to recognize that class is important for some patients, but it's but it's not doesn't mean the same thing across the disease. Specter of melanoma patients. And so this is the this is the univerity and multi varied analysis and was also shown in the previous discussion that a multi variant model gene expression profile was important and maybe more important than sentinel lymph nodes stuck status in this trial. They're pretty similar. Relapse free survival and distant metastatic disease free survival. Um have pretty similar, pretty similar um hazard Rachel's. Um So this is really interesting data as well. You can see the numbers of patients with class one, Class two central negative positive. So the best patients are class one and central no negative. The worst patients are class two and central infinitely positive. But it's important to recognize and having one or the other is relevant as well, which means that they don't completely overlap. So you have centered on the negative patients that are clashed to that do poorly. And you have class one patients that are central if not positive, that don't do so well also. So that's one of the arguments that I would make a gangster to just routinely saying that we should do. We should look at class for all the stage one and two patient populations. And it's because that's a continuum of stage. It's hard to imagine that every single 1.8 millimeter, also rated patient, that's a stage. It's a clinical stage to patient with a class one would have a very low risk of a positive center. Now, that's absolutely not true. So, so class doesn't mean the same thing across the different stages. So this is the mala gen X. Data of a similar group of patients. This is an 11 gene gene expression profile was validated across the stage, you know, one through three group and this is all A. J. C C eight. Relapse free survival, anonymous specific survival, high risk versus low risk. This is the stage three patient population. This is the low risk group versus the high risk group. And this represents almost a third of the patients fall into this low risk group and this is the three A. And three B. The lowest, doing better than the high risk. But look how well the low risk group does in the three A and three B. If we go back to this kind of hypothesis chart, if we included this gene expression score for the 11 gene, you could identify a very low risk group. So a third of the patients with the three states, three patients would be patients that have a very good survival outcome and not likely to benefit from a gene therapy. This is the class one versus class two in the uh um 31 gene and szaggars paper. Uh This is the this is the stage to patient population. The class one versus class to again, Class one doesn't mean the same thing across stage. And this is the 11 gene stage to patient population. Uh low risk, low risk versus versus high risk and I'll stop there related to the gene expression profile and make a few comments about expanding central national biopsy in some of the other high risk malignancies, particularly Merkel cell because it's important for prognosis and now important for treatment and the high risk squamous cell cancers. Uh which you heard a lot about in the in the noon hour I think I have five minutes left and I think I can do that. So um in terms of gene expression profile, just have a short conclusion, objective predictors of metastatic risk in the high risk stage two and stage three groups we need like independent uh it's clearly independent of traditional staging, a pregnant and prognostic models and certainly can help individualized risk. But we need to have prospective valuation cohorts linked to ongoing education therapy trials. Or look back at other adjunctive therapy trials and see if we can better stratify using gene gene expression profiling to identify risks so we can better personalize recommendations for patients and design trials that would select patients with high risk gene expression profiling. Let's talk about Merkel cell where in highly aggressive neo plasm of the skin. I think we all know it's mostly in the elderly population, have a high risk for recurrence and metastasizing to regional disease early on. When we looked at central lifting a biopsy, a study from memorial Sloan Kettering predictor 55 year predictions was tumor stage diagnosis and that would include five year overall survival based on sentinel lymph node status as well, 74 4% versus 97%. Um um overall 97 versus 52% for central no negative versus central if not positive tumor side also was a predictor um in in the in the know negative patients. But central if not positivity was a great predictor of outcome. And that was incorporated as part of the N. C. C. And guidelines for most primary merkel cell carcinoma patients. And these are individual studies for male and from memorial Sloan Kettering, both showing that sentinel lymph node status um was very important in terms of predictor uh predictor of outcome. This is a 5823 patients from the national count the National Cancer Database assessment of primary tumor size and a note positive versus versus versus pathologic note positive. So clinically no negative patients here. But when we when we identified the pathologically no negative patients they did much better because you removed the node positive patients into the next stage. So again pathologic normal status was an excellent predictor of outcome for patients with merkel cell carcinoma. So again uh Clinically node positive. I'm sorry um clinical not positive versus um versus clinically no negative but pathologically note positive. 59% vs 76% in five years. So the N. C. C. N. Guidelines that are shown here that central lymph node biopsy is is for patients that are clinically no negative that we would management of the draining lymph node basin central left on positive. We have baseline imaging of sentinel lymph node negative. They were just observed and how that's shown here. This was supported by the european consensus based interdisciplinary guidelines. From 2015. The central government biopsy was recommended by the E. D. F. And the A. D. O. As well as the O. R. T. C. Sentinel negative observation of the basin center live no positive, recommend completion dissection or consider achievement X 30 in the setting of patients with per per per performance status. And that brings us to the last issue which is um squamous cell cancer. And I would agree this is emerging as a very important public health problem. There are more than a million cases annually Generally treated and usually cured with adequate local therapy. But there is a small group of patients 2-6% of development metastases. And the most common metastatic uh feature is regional lymph node basin That translates into at least 7000 new deaths a year. Makes this just as an important public health problem as melanoma and maybe greater. I wanted to use a case presentation to illustrate the importance for sentinel lymph node involvement. 64 year old patient with Bulky left inguinal disease that I saw with significant nodal disease. Had a prior history of a screening for cancer of the skin of the left lower back that was excised with negative margins. Two years prior to that I saw the patient there was no local and transit disease. The staging work up was negative. The patient did receive systemic some implement mob. And because the patient went on a clinical trial has significant partial response. You can see the response compared this is the presenting disease and response after cynical a mob is here. Nice, excellent response in this patient. We went back and looked at the primary tumor and interestingly enough it was greater than 1.5 cm in diameter with six in thickness. They had Perry Neural invasion and it was poorly differentiated. So what is what was the natural history was this predicted predictable with a center left a biopsy identifying microscopic disease. And that's important because in reality what happened to this patient actually had a therapeutic dissection, had a big operation, had adamant radiation but still developed all this terrible regional and transit disease and local recurrence. So these are the predictors of nodal disease size thickness, incomplete excision, recurrent tumor grade perry Mueller invasion site like ear lip and genital immuno compromised patients. And there is little experience with sentinel node biopsy. But some but most of the data that we have is related to a single institution experiences or collective experience of 607 patients where it was with anal genital squamous cell cancer, 24% sentinel lymph node positive, false negative rate was relatively low. And there are 84 85 patients in this group that had nominated genital squamous cell mate a 21% center left and positive, hoping that identifying sentinel lymph node disease could prevent terrible regional disease. And this is our similar data data as well. It's interesting. The NCC and guidelines talks very little about sentinel node but it says on certain high risk lesions. Consider sentinel lymph node mapping. Although the benefit of this technique is has to be proven for certain high risk claims, sentinel node biopsy mapping may be considered. Clearly routine use is not indicated, but we need to better identify the high risk patients right now. It's kind of it's kind of all over the map and we need prognostic value of microscopic nodal involvement, the potential to improve regional disease control and potential survival impact the NCC and guidelines identifies high risk is having one of these features, surprisingly the percentage of patients that fall into this high risk group is pretty low actually, but since women so cancer is so common, it translates into a relatively large number of patients. We need large, multi center databases with long enough follow up, including all relevant factors and multi varied analysis to determine the independent predictors of recurrence and survival. And you had a very excellent discussion about the 40 gene expression profile for this disease and this this data looks looks amazing and and which suggests that even though some of these patients are identified as high risk, most of them are actually low risk based on a class of one finding. So clearly, those patients don't need any extensive follow up or extensive management. The problem with some of this data is that we currently don't have any approved adjuvant systemic therapy for patients with positive nodes or with or with high risk to us. But certainly we could potentially use this data to identify the truly high risk group and consider sentinel lymph node by. I've seen those patients and I'll stop there and thank you very much for your kind attention. I was a few minutes over but I think we started seven minutes late. Thank you, Merrick. We actually had several questions sent in. We will afford those to you and uh and we'll get back to the attendees with the answers.
