Treatment De-escalation for Favorable Ri...

Dr. Chino talks with Dr. Atif Khan and Dr. Lola Fayanju about the shift in breast cancer management from reducing locoregional recurrence and improving breast cancer mortality to deintensification, shared decision making, and improved quality of life. This discussion will be based off a JCO OP editorial published in late 2024 called "Contextual Framework for Understanding Treatment De-Escalation in Patients With Breast Cancer."

Transcript

Dr. Fumiko Chino: Hello, and welcome to Put into Practice, the podcast for JCO Oncology Practice. I'm Dr. Fumiko Chino, an Assistant Professor in Radiation Oncology at MD Anderson Cancer Center with a research focus on access, affordability, and equity.

Breast cancer treatment has made significant strides in the past century, with the five-year survival rate rising from less than 5% in the early 20th century to around 90% in the present day. In today's episode, we'll be discussing the shift in breast cancer management from reducing local-regional recurrence and improving breast cancer mortality to deintensification, shared decision-making, and improved quality of life. This discussion will be based off of a JCO OP editorial published in late 2024 called "Contextual Framework for Understanding Treatment De-escalation in Patients with Breast Cancer."

I'm excited to welcome two breast cancer experts as guests today: the first author of this editorial and radiation oncologist, as well as a health services researcher and breast surgeon. They're both engaged in research to improve outcomes for breast cancer, including treatment optimization.

Dr. Atif Khan, MD, MS, is a full attending breast cancer disease site leader and Service Chief in the Department of Radiation Oncology at Memorial Sloan Kettering Cancer Center. He is also on the steering committee of the Clinical Research Innovation Consortium, as well as on the Research Council at MSK. Dr. Khan is the chair of the breast section of oral examiners for the American Board of Radiology and is active in NRG, helping develop and lead key clinical trials to optimize radiation delivery for breast cancer. Dr. Khan is also a translational science investigator of novel radiosensitizers.

Dr. Oluwadamilola "Lola" Fayanju, MD, MA, MPHS, is the Helen O. Dickens Presidential Associate Professor and Chief of the Division of Breast Surgery at the Perelman School of Medicine at the University of Pennsylvania. She is also Surgical Director of the Rena Rowan Breast Center at the Abramson Cancer Center, Program Director for Implementation Innovation at the Penn Center for Cancer Care Innovation, and a Senior Fellow at the Leonard Davis Institute of Health Economics at Penn.

Our full disclosures are available in the transcript of this episode, and we've already agreed to go by our first names for the podcast today.

Atif and Lola, it's wonderful to speak to you today.

Dr. Atif Khan: It's a pleasure to be here. Thank you for inviting me, Fumiko.

Dr. Lola Fayanju: Yeah, thanks for having me.

Dr. Fumiko Chino: The topic today is treatment de-escalation for breast cancer, loosely based on the editorial that Atif wrote in JCO OP outlining a conceptual framework, which is primarily focused on local-regional therapies, i.e., radiation and surgery for breast cancer. The concept of rightsizing treatment has really been developing over the past three decades, spearheaded by surgical de-escalation. Lola, do you mind giving me a brief overview of surgical de-escalation as you have seen it throughout history and as currently realized in your practice?

Dr. Lola Fayanju: Happy to. So, you know, it's one of those things where I think increasingly we recognize that breast cancer is a heterogeneous condition that shares an anatomical space. And with that refined understanding of treating breast cancer, we're no longer using a very blunt and large hammer to deal with what is actually a constellation of nails. So originally, when people used to treat breast cancer, the idea was that you wanted to take as much tissue as possible. And this originated the Halstedian mastectomy, which was a radical mastectomy that often involved removal of not only all the breast and axillary tissue but also the pectoralis muscle, even some accessory nerves, that really left people with incredibly deformed body habitus as well as compromised function. And in part, that was not an unreasonable approach given that disease was often presenting in a locally advanced fashion.

However, as we have been increasingly able to detect disease at an asymptomatic, pre-palpable state, but also as our ability to treat disease at a systemic fashion has become more effective, we've been able to move from the Halstedian mastectomy to then the modified radical mastectomy, and then ultimately to even less axillary surgery, as well as less breast surgery, such that there was the advent of the lumpectomy pioneered by Bernie Fisher in the 1980s, as well as sentinel lymph node biopsy pioneered by Armando Giuliano and Don Morton in the 1990s and early 2000s. And what this allowed us to do, again, is to achieve similar if not better outcomes, because we were again catching disease at an earlier state thanks to screening mammography, but also able to provide more personalized, less morbid care that focused on just the cancer at hand with the additional adjuvant therapy of radiation to provide comparable survival to mastectomy.

What this has allowed us to do is also think about the order in which we do treatment, that is allowing people to potentially get systemic therapy first in order to convert from a more morbid procedure to a smaller, less morbid procedure. So, we've made a huge number of strides both with regards to surgery in the breast as well as surgery in the axilla, and that's been facilitated by a combination of knowing more about disease, being able to be more systemic and holistic in its treatment, and also recognizing that more is not always more. The last thing I will say is that we've also been aided not only by the adjunct radiation and systemic therapies, but also by the ability of our radiologists to localize pre-existing cancer such that we can target the area and just the area of concern, whether it's through targeted axillary dissection or through sampling a previously positive area of the breast, such that we can again be more selective in terms of the surgery people get after systemic therapy.

Dr. Fumiko Chino: Thanks for that great overview, and I really love it how you have highlighted that it's all of these advances that allow us to customize the treatment to the individual. So it's not one size fits all with cancer care. We're really trying to make a customized plan and really rallying all of the modern technologies to make sure that we're rightsizing the treatments for the individual. And I think that provides a lot of benefits for patients.

Atif, can you highlight some of the key steps to de-escalate radiation for breast cancer?

Dr. Atif Khan: I think thematically, we're seeing a very similar sort of trend in radiotherapy. Just as a reminder, radiotherapy is a critical component of breast conservation therapy and also in the post-mastectomy context for high-risk patients. Radiation has been shown to sterilize or reduce the risk of microscopic residual, reduce the risk of local-regional recurrence, and in high-risk contexts, you know, by extension, reduce the risk of all recurrences and even improve survival, for example, in the seminal post-mastectomy radiation therapy trials.

Now, we existed in a time when there was perhaps only one right way to do radiation therapy, and that's not the case now. We have many different ways that we can deliver radiation therapy. And that's important because our, as Lola said earlier, our understanding of different risk strata of breast cancer has also improved, meaning we can stratify breast cancer patients into low risk, intermediate risk, high risk, maybe even very low risk. And therefore, we can tailor the intensification of our local-regional treatments to match the background risk that may exist for that particular patient.

Now, if we consider five weeks of whole breast radiation or five weeks of post-mastectomy radiation to sort of be our historic norm, we now know that we don't have to protract the course of radiation out like that. We can treat that same target volume, for example, the whole breast, with a shorter course of radiation that generally is given over three weeks. Now, I do want to pause here for one second just to clarify for everyone listening: taking five weeks of whole breast and doing that over three weeks is not necessarily a de-escalation per se, because really the same biologically effective dose is being given. It's just being given faster. So it's not really a treatment deintensification or de-escalation per se. Now, it is less disruptive to patients, it might be less, say, financially toxic, for example, in terms of like missed days of work, etc., but it's not a de-escalation with respect to the intensity of the treatment. It's just the same treatment being given shorter, but we know that it's safe to do that.

In contrast, partial breast radiation is, in fact, a de-escalation because now our target volume is no longer the entire breast, rather, we're just treating a part of the breast, that part of the breast where the risk primarily is, which is in the index quadrant where that original breast cancer was. And at the, let's say, at the low end of the risk spectrum, we now have very good evidence, you know, 14,000 randomized women, demonstrating that, in fact, partial breast radiation in those contexts is just as good as whole breast radiation. And I always sort of half-joke that whenever this treatment is possible, we should use it because for a fibroblast sitting in the breast somewhere minding its own business, a day without radiation is a good day, right? So if we can spare that treatment to uninvolved normal cells, we should try to do that.

And then, of course, the ultimate de-escalation is to identify patients who don't need radiation at all and just omitting radiotherapy. And really across the risk spectrum, whether it's in breast conservation or whether it's in PMRT/regional nodal radiation, we are seeing the emergence of these different types of treatments, meaning kind of like the high-risk treatment, the intermediate-risk treatment, and then at the very low end of the risk spectrum, no treatment at all. But that's sort of the practice that we're living in now, and I think it's a good one. We're making progress.

Dr. Fumiko Chino: I appreciate that. The whole idea is if we can potentially omit treatment to certain areas of the body or if we can omit it completely, we're certainly doing a favor for our patients if it's not going to increase their overall risk. We had talked, I think between the two of you, about some of the benefits of potentially omitting or reducing morbidities from, for example, surgeries or comprehensive treatments. Atif, do you want to take it first? What are the actual de-escalation risks? What are we potentially putting at risk when we talk about de-escalation or deintensification?

Dr. Atif Khan: Yeah, great question. I mean, I think the primary risk, which is, you know, a scary thought, is that we de-escalate or we do it too quickly or we find that, in fact, reducing the intensity of treatment leads to an increase in the recurrence risk of breast cancer. That's a very scary thought. I will say that this process of creating options, you know, treatment options, de-escalated treatment options, has been quite successful. For example, I'll open it up to Lola and you, Fumiko, but I can't really think of a clear example in which the de-escalation trial went in the wrong direction. Like, they've all sort of gone in the same direction, which is that the de-escalation or deintensification studies have generally been successful, meaning that we were able to preserve the excellent oncologic outcomes that we are used to seeing with less treatment. That's a testament to kind of how careful, you know, the scientific process is with respect to these practice-defining trials. They go through multiple levels of scientific review. It's a multidisciplinary group of individuals that's looking at this. And I would say the endeavor overall has been quite successful.

Dr. Fumiko Chino: Lola, anything to add?

Dr. Lola Fayanju: Yeah, I think when we're thinking about the risk of de-escalation, I would put them into three categories of risk. So, there are risks to the individual, that is, you know, we're actually de-escalating in the wrong person because we have an insufficient amount of information about whether they meet the criteria for de-escalation.

There's, I think, risk to the population in terms of are there groups of people who are systematically not benefiting from the de-escalation or who should not be benefiting from de-escalation because again of an underappreciation of how disease might work in that group or because the practice patterns where those people are getting care will not be amenable to de-escalation ultimately being of a good thing for them because they're not getting the other components of care that frankly are needed for de-escalation of one modality.

And then three, I think there's a risk to our collective knowledge about cancer because when we're not collecting information about what happens after six weeks of radiation or how many lymph nodes are positive, we just know a little bit less about the natural history of the disease and the natural sequelae of treatment. Again, that knowledge may be worth forgoing given the morbidity to patients and the non-benefit with regards to recurrence and survival, but it's real. It means that our retrospective reviews look different. It means our ability to have preliminary data for other types of things look different. With regards to the populations, it means that whenever we're thinking about de-escalation, we need to think hard about how to translate what we see on the podium at San Antonio or ASCO into clinical practice. And that requires, I think, more care than is often administered.

Dr. Fumiko Chino: Yeah, I'll quote directly from the manuscript of the editorial that we are basing this podcast on, and it said basically, "American women ascribe a high utility to remaining without evidence of disease." And that really sticks with me in that, even though there may not be a survival benefit, an increased risk of recurrence is not without a personal, financial, and physical burden on patients, even if that difference is small, it may be meaningful for the person in front of you.

Now I'll also shift focus slightly and just mention that we're primarily talking about local therapy here, but I'd be remiss to not highlight that there are gains in de-escalation for systemic therapies from, for example, RxPONDER, allowing us to safely omit adjuvant chemotherapy for many node-positive patients; B21, showing that monotherapy with radiation may be actually even better than tamoxifen monotherapy with no metastatic or survival differences; and of course, the PERSEPHONE trial that demonstrated that six months of trastuzumab was non-inferior to 12 months, although, granted, there were many caveats leading to poor adoption of this in practice.

Now, Lola, I know you've already mentioned this, but there are maybe some concerns that you see about broad adoption of these practices into, for example, surgical de-escalation. Based on what I know is stark disparities in clinical trial enrollment in certain populations or in maybe even clinical trial protocol adherence, are there any specific populations that you want to highlight that might be hesitant to apply this clinical trial podium data to?

Dr. Lola Fayanju: That's a great question. So, as an example, when we think about the SOUND trial, which was recently published and demonstrated that in women with early-stage breast cancer who were undergoing breast-conserving therapy and had normal axillary evaluation prior to surgery, that sentinel lymph node biopsy could be safely omitted without detriment with regards to long-term outcomes, you need to think about the context in which that preoperative ultrasound is being done. So, at different institutions, whether or not an ultrasound is routinely done, whether or not that ultrasound is done prior to biopsy, all of these things have implications for how likely you are to have a false positive after biopsy (so it's preoperative, but it's post-biopsy) and also what you're going to do about it, whether you're going to act on it, whether you're going to go ahead and proceed with sampling that node if it looks enlarged, putting something in it that means you retrieve it. If it demonstrates a small amount of cancer, potentially consigning someone to either an axillary dissection or preoperative systemic therapy that they might have forgone had you had the full picture of surgical pathology.

So that's just one example of how the context in which implementation occurs is really important because you have to take into account local practice patterns and what that means with regards to how we interpret the data that was used in the trial to then implement this practice in real life.

With regards to populations that need to be considered, I think in terms of centering equity, both domestically but also at a global level, thinking about, for instance, how we stage the axilla, how we map the axilla. What's the facility for lymphoscintigraphy as well as for localization of a previously positive node? So, there are many countries, many quite wealthy countries, in which use of radiocolloid is not routine, where it is primarily that people are using some type of tracer blue dye, for example, and therefore would not strictly be meeting the criteria for optimal sentinel lymph node mapping that would allow for a low false negative rate after neoadjuvant systemic therapy.

In the United States, we might be in places where you have patients who are having surgery with people who don't do that much breast surgery and who are less likely to have a successful and correct yield of lymph nodes at time of sentinel node biopsy. And so, you know, these are people for whom there might be actually clinically significant disease that's being left behind if not being done by someone who has a lot of experience working with dual tracer as an opportunity to localize a preoperatively positive lymph node. So again, thinking about both the availability of materials as well as the expertise of the local practitioners means that people in less or differently resourced settings may not benefit from implementation in a way that actually leads to appropriate outcomes.

Dr. Fumiko Chino: Yeah, I love it how you highlight that there's global differences, but there's also just in the US differences in capacity and skills within doing these, some of these presurgical and surgical evaluations. All three of us work at world-leading cancer centers, and I recently just transitioned from two top cancer centers in the United States, but I was actually kind of shocked about the differences even between the two major centers about how we do ultrasounds, for example.

Now, Atif, I've noticed that some providers don't really feel comfortable combining the information from various de-escalation trials in practice, i.e., so for some patients that might have had sentinel lymph node biopsy omitted per SOUND, they may be less likely to actually get PBI and instead, you know, prefer to treat whole breast radiation to cover the axilla. So, in this respect, it seems like we're kind of taking like one step forward, one step back. And are we de-escalating surgery to just escalate radiation?

Dr. Atif Khan: Fumiko, I agree with you. It'd be very counterproductive if we found that de-escalation in one domain was leading to escalation in another domain. I think the example you cite is a good one. If we are moving to a world without sentinel node biopsy and let's say clinical staging only, does that then mean that we have to, for example, give up on partial breast irradiation and treat everybody with whole breast radiation on the notion that low axilla, for example, is going to get some therapeutic effect? And I would submit for everyone's consideration that no, we in fact should not do that. We spent years developing the partial breast irradiation literature. We know that PBI has less acute toxicity. In every single trial, it has less fatigue, and it actually has less late toxicity in some studies, which is not surprising because remember, you're treating less tissue, you're treating less stuff, and that's a good thing.

Now, coming to SOUND and INSEMA, on the sentinel node arms of both of those studies, the rate of additional positive nodes is very- around, 10%, and that's pretty low. So I would submit for everyone's consideration the idea that if your patient is node-negative by SOUND criteria, let's say, right? They're very likely to be pathologically node-negative. And you can actually treat them as if they were pathologically node-negative. And that's kind of how we've adopted the findings of both SOUND and now also INSEMA from San Antonio, meaning that if a patient is eligible for PBI based on everything else, and she is node-negative by SOUND criteria, then we will offer them PBI in exactly the same way as we were before these trials were reported.

I also wanted to make one observation on your prior comment, Fumiko, if I may, about the de-escalation of systemic therapy. One thing that has been on my mind quite a bit is, particularly with, let's say in the elderly group where we have been struggling with kind of like the best monotherapy, right? Should it be five years of endocrine therapy? Should it be a short course of radiation, or do patients really need both of these treatments? And this is topical because the EUROPA trial, one of the endpoints was reported at San Antonio, the quality of life endpoint. Not surprisingly, a short course of radiotherapy was sort of associated with better quality of life than the endocrine therapy.

But I think we may be missing one potential opportunity in this sort of idea of like, we have to either do the radiation or the endocrine therapy, which is we might be able to give a little bit of systemic therapy and a little bit of radiation therapy. This line of investigation or line of thinking doesn't really exist right now. Like that conversation is interesting. So for example, can we give, for number one, can we go from AI back to TAM, right? Because AIs are just, there's just, the quality of life is worse. And can we give a lower dose of the TAM, monitor for compliance, and then give a little bit of radiation, you know, let's say PBI or something? And maybe that's the way to do that. And you could take that idea and you could apply it across different contexts even in breast cancer. And I'll note that that is how kind of the Hodgkin's lymphoma treatment evolved over time. At the low end of the risk spectrum, they kind of said, "Okay, a little bit of chemo and a little bit of radiation is better than just giving a lot of chemo or certainly a lot of radiation." And you know, that worked. And I think at the low end of the breast cancer risk spectrum, we might start thinking about that kind of line of investigation.

Dr. Fumiko Chino: You want to 'Goldilocks' this situation. You want to try to find something that's just right. And I love that. And I think that sort of out-of-the-box thinking is very helpful when we think about how omission seems very clean, "you just don't get this," but deintensification, simultaneous deintensification, I think has a lot of appeal there.

Lola, do you have anything to add about that?

Dr. Lola Fayanju: I have to acknowledge the bias of three local-regional therapists on this podcast, I'm outnumbered by our two rad oncs. But just wearing my medical oncology ally hat, I think one of the challenges is also that for many of them, the ability to prescribe effective forms of systemic therapy, including CDK4/6 inhibitors, for example, is sometimes predicated on information we obtain at surgery. So, when we think about implementation, which is really, you know, an area of research for me, whether it's trying to implement the SOUND trial, again, in an institution where everyone's getting an ultrasound prior to biopsy, absolutely. But in an institution where either it's completely ad hoc, so it's kind of the 'wild, wild west', you have no idea from radiologist to radiologist who's doing ultrasound before or after biopsy, and also frankly, what is the kind of false negative rate at that institution, recognizing not everyone's working at the kind of places we work at. Are we doing patients a disservice?

But then, in addition, thinking about working with insurance companies, right? If we're trying to say, "Okay, we are no longer going to do sentinel node biopsies," but that's actually required for the administration of certain medications, we put our medical oncology colleagues in a bad position in terms of their ability to actually get certain types of treatments paid for and approved. And so again, thinking about the consequences of our choices for patients, I think it really points to the fact that multidisciplinary consultation is increasingly going to be needed because we can't de-escalate everything. I think we all agree most cancers need to be treated in some fashion. But, you know, if we take away surgery, we take away radiation, we take away systemic therapy, suddenly we have a cancer that's just sitting there. And for some people, that's the right thing. Again, thinking about shared decision-making, for some patients with other morbidities and/or older age where they're unlikely to have any kind of meaningful threat from disease being left in place, well, that is the right thing potentially. But for a majority of our patients who actually want some form of treatment, I think we do need to think about the implications for our other prescribing providers, what that means, how we can help them, even as the clinical trial data suggests that there aren't major changes in adjuvant therapy or radiation prescription when you omit sentinel node biopsy, at least in the trials that have so far been shown.

Dr. Fumiko Chino: This is a nice segue to my last point, which is to talk about how these discussions of de-escalation, these decisions should really be made after the full multidisciplinary input. And yet, I feel like I've seen our specialties get increasingly disconnected in this kind of era of Zoom conferences. There seem to be less face-to-face meetings. There seems to be decreasing space for our co-shared clinics. And I just wanted to ask both of you what you think our responsibility is to each other and to our field to ensure that we're really working on these things synergistically.

Lola, you just mentioned some of your thoughts, but do you mind speaking about the multidisciplinary conversation or even how we're designing research?

Dr. Lola Fayanju: I think, with regards to the research, I'll start with that first, it means that, I think we're less going to have trials that fit in certain kind of cooperative groups that are more geared towards radiation or what have you. I think, increasingly, we should be having MPIs, you know, co-PIs who are from different modalities. I think that that's going to allow us to bring our different lenses to constructing the trial, to ultimately interpreting the result. I think we'll only grow from that. I think the era of having a bunch of medical oncologists or surgeons or radiation oncologists as the primary authors really should probably shift.

I think we need to think more globally about multidisciplinary care and what those, quote unquote, "tumor boards" should look like. And thinking beyond our own institutions, again, we're relatively privileged in terms of being at places where we all have at least weekly, if not bi-weekly multidisciplinary tumor boards. Most cancer care in the United States is happening in the community where a patient walks into, often a general surgeon's office, and that person will get surgery upfront whether they need it or not, or whether they should be getting systemic therapy or not first. And then from there, they will then be referred to a medical oncologist who may have had no input as to which procedure should have been omitted or discussed or vetted prior to meeting that person. And so, I think our greater challenge is how to bring in the global oncology community, and by global, I mean truly across the globe, across the United States, across the world. And it might be that ASCO and JCO, places like this for discussion, is an opportunity for us to connect people, connect our communities, and not having us work in silos, both at the institutions in which we currently are employed, but also at a broader level.

Dr. Fumiko Chino: Wonderful statement. Atif, anything to add to that?

Dr. Atif Khan: Yeah, I think you're pointing out an important thing, Fumiko, which is, you know, we are somewhat more fragmented since the pandemic, and we're kind of in our own spaces, and that is potentially a problem. I think in breast cancer, the different specialties are often existing in kind of a very cooperative matrix, and I think that ends up meaning that we're able to really provide high-level care to our patients. I think there are other specialties, I know, where the specialists may be existing in a somewhat more competitive matrix with each other, and I think that ends up potentially being counterproductive for patient care. So I think this is probably a thing that we need to have more conversation around and sort of thinking about how do we bring the different vantage points together in the interest of the patient and not lose that multidisciplinary care that we'd become so used to and that's provided such excellent outcomes.

I think on the research side, I don't want anyone to sort of be left with the idea that there's just one specialty that's sort of driving, you know, the design of these trials. From my own first-hand experience, both at Alliance and NRG, there's a lot of scientific review that happens, and I spent quite a bit of my energies over the past decade and a half kind of convincing medical oncologists that a certain local-regional question is warranted. And, and you know, that's part of the process. I appreciate that because they're not just experts in their field. You know, we all eat, breathe, and live breast cancer. So, you know, they have keen insight into the local-regional management as well.

Dr. Lola Fayanju: Yeah, I have to say I love the cooperative group meetings. That's kind of where the sausage gets made. And I think it is really exciting that you have people from different disciplines sitting together, proposing trials, vetting them. It feels like you're seeing the future in the present, which is really exciting. And, you know, I think what we're all striving to do.

Dr. Fumiko Chino: I love that hopeful conclusion, and I really am so grateful for both of you for this wonderful conversation today. Many thanks to both Dr. Khan, Dr. Fayanju, as well as our listeners for your time today. You will find the links to the papers that we discussed in the transcript of this episode. If you value the insights that you hear on the JCO OP Put into Practice podcast, please take a moment to rate, review, and subscribe wherever you get your podcasts. I hope you'll join us next month for Put into Practice's next episode. Until then, I encourage everyone to continue doing the work that they find meaningful for their patients, for their community, and for themselves.

Dr. Atif Khan: Thank you.

Dr. Lola Fayanju: Thanks so much.

The purpose of this podcast is to educate and to inform. This is not a substitute for professional medical care and is not intended for use in the diagnosis or treatment of individual conditions.

Guests on this podcast express their own opinions, experience, and conclusions. Guest statements on the podcast do not express the opinions of ASCO. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.

Disclosures:

Atif Khan: Stock and Other Ownership Interests: Novavax, Xtrava; Research Funding: Clovis Oncology, Merck KGaA, Varian Medical Systems; Patents, Royalties, Other Intellectual Property: Use patent for the drug riluzole awarded to Rutgers University with me as inventor.

Oluwadamilola Fayanju: Research Funding: Gilead Sciences