Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline

An interview with Dr. David Schiff from the University of Virginia Medical Center in Charlottesville, VA, and Dr. Michael Vogelbaum from Moffitt Cancer Center in Tampa, FL, co-chairs on "Treatment for Brain Metastases: ASCO-SNO-ASTRO Guideline." This guideline comprehensively addresses the treatment of brain metastases from non-hematologic solid tumors, including surgery, systemic therapy, radiation therapy, and timing of therapy. Read the full guideline at www.asco.org/neurooncology-guidelines.

TRANSCRIPT

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SPEAKER 1: 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. The mention of any product, service, organization, activity, or therapy should not be construed as an ASCO endorsement.

BRITTANY HARVEY: Hello, and welcome to the ASCO Guidelines podcast series brought to you by the ASCO Podcast Network, a collection of nine programs covering a range of educational and scientific content and offering enriching insight into the world of cancer care. You can find all the shows, including this one, at asco.org/podcasts. My name is Brittany Harvey, and today I am interviewing Dr. Michael Vogelbaum from Moffitt Cancer Center in Tampa, Florida, and Dr. David Schiff from the University of Virginia Medical Center in Charlottesville, Virginia, Co-chairs on Treatment for Brain Metastases, American Society of Clinical Oncology, Society for Neuro-Oncology, and American Society for Radiation Oncology Guideline. Thank you for being here, Dr. Vogelbaum and Dr. Schiff.

MICHAEL VOGELBAUM: My pleasure.

BRITTANY HARVEY: Before we begin, I'd like to note that ASCO takes great care in the development of its guidelines and ensuring that the ASCO conflict of interest policy is followed for each guideline. The full conflict of interest information for this guideline panel is available online with the publication of the guideline in The Journal of Clinical Oncology Dr. Vogelbaum, do you have any relevant disclosures that are directly related to this guideline topic?

MICHAEL VOGELBAUM: I have no disclosures relevant to this guideline.

BRITTANY HARVEY: Thank you. Then, Dr. Schiff, do you have any relevant disclosures that are directly related to this guideline topic.

DAVID SCHIFF: Hi, Brittany. No, I do not.

BRITTANY HARVEY: Great. Then first, Dr. Schiff, can you give us an overview of the scope and the purpose of this guideline?

DAVID SCHIFF: Sure. Our overall purpose was to provide guidance on the appropriate treatment of adult patients with parenchymal brain metastases from solid tumors, encompassing surgery, radiation, and systemic therapy, as well. Previous guidelines in this area were for the most part produced by neurosurgeons and radiation oncologists for their respective professional organizations, although they did incorporate multidisciplinary input. But over the last decade, treatment options for certain types of brain metastases have undergone a substantial change.

The expanding armamentarium for medical oncologists in treating both extra-CNS disease as well as brain metastases highlighted the need for a new set of guidelines to evaluate the role of systemic approaches, such as targeted agents and immunotherapy, for the primary treatment of brain metastases in the context of more established treatments like surgical resection, radiosurgery, and fractionated radiotherapy.

Additionally, recent studies have clarified the role of radiation techniques like whole brain radiation with hippocampal avoidance and radiosurgery to surgical resection cavities. By assembling a multidisciplinary group of experts from surgical neuro-oncologists, medical oncologists, neuro-oncologists, and radiation oncologists, we sought to provide as comprehensive and up to date a set of therapeutic guidelines as possible.

In order to accomplish this, the panel performed a systematic review of randomized as well as nonrandomized evidence from 2008 through April, 2020. We focused on the roles of surgery, systemic therapy, and radiation therapy, as well as the timing and interactions among these modalities. And we included all randomized clinical trials, as well as large single arm phase II studies and institutional case series, and we also reviewed case control and cohort studies.

BRITTANY HARVEY: OK, great. That's helpful background. And then you mentioned a couple focus areas, as well, of the systematic review. And so I'd like to review the key recommendations that were based off that evidence.

So, starting with surgery, Dr. Vogelbaum, what are the key recommendations for surgery in adult patients with brain metastases?

MICHAEL VOGELBAUM: So, the role of surgery, I think, was well established via randomized trials to some degree, and then via some of the larger single arm studies. Patients with suspected brain metastases without a primary cancer diagnosis were felt to benefit from surgery to obtain a diagnosis and undergo removal of the tumor. But more to the point, patients with larger tumors with mass effect-related symptoms are the ones most likely to benefit from surgery. What we also noted was that patients who have multiple brain metastases with extensive and uncontrolled systemic disease are unlikely to benefit from surgery unless the remaining disease is controlled via other measures, typically medical measures.

We also contemplated the type of resection performed, the technique being used. There was some developing literature looking at the techniques of either an en bloc resection or a piecemeal resection. And when we critically evaluated the literature, we felt that no recommendation could be made regarding the method of resection, as there was not sufficient evidence to support one approach over another.

Another technique that is being used more recently is the use of laser interstitial thermal therapy, which is a minimally invasive technique to treat tumors in general. But again, there was insufficient evidence to really be able to make a recommendation for or against the use of LITT, as it's called.

BRITTANY HARVEY: OK, thank you for reviewing both those techniques and those recommendations and highlighting where there wasn't enough evidence to actually make a recommendation. So, then, following that, Dr. Schiff, what does the guideline recommend for patients with brain metastases regarding systemic therapy, including chemotherapy, immunotherapy, and targeted agents?

DAVID SCHIFF: Brittany, there is a role for systemic therapy as the initial or primary modality in some cases, but I think it's really important to emphasize this only pertains to patients whose brain metastases are asymptomatic and those with particular histologies or molecular profiles. So, there are really-- there are three primary sites for which targeted or immunotherapy can be considered.

The first is non-small cell lung cancer, for which osimertinib, or if you're in China, where there's access to another drug called icotinib, specifically for EGFR-mutated disease, alectinib, brigatinib, and ceritinib are appropriate approaches in ALK-rearranged asymptomatic brain metastases. And finally, pembrolizumab in combination with pemetrexed and a platinum agent in immunotherapy naive patients whose tumors express PD-L1.

The second primary tumor is melanoma. And for melanoma patients who have asymptomatic BRAF V600E mutant brain metastases, dabrafenib with trametinib is an appropriate option to consider. For all melanoma patients with asymptomatic brain metastases, ipilimumab with nivolumab is also an option. And finally, for breast cancer, the combination of tucatinib, trastuzumab, and capecitabine for HER2 positive asymptomatic brain metastases in patients who have progressed on previous anti-HER2 antibody therapy. When patients treated with systemic therapy progress intracranially, local therapies such as surgery, radiation, and radiosurgery should not be deferred.

BRITTANY HARVEY: OK, those are helpful notes for clinicians, and particularly around the primary tumor sites. So, then, Dr. Vogelbaum, what are the key recommendations for radiation therapy in patients with brain metastases?

MICHAEL VOGELBAUM: So, Brittany, the panel started by noting which patients would not benefit from radiation therapy, in particular, those with asymptomatic brain metastases and a poor performance status, with a Karnofsky Performance Score, or KPS, of less than or equal to 50, or performance status of less than 70 and no systemic therapy options. In those cases, radiation therapy is unlikely to be of real benefit.

But then when speaking to the different modalities of radiation to be used, a lot of the review focused on the two most commonly used modalities, which is Stereotactic Radiosurgery, or SRS, versus Whole Brain Radiotherapy, or WBRT. And the first recommendation was that SRS alone as opposed to either whole brain radiotherapy alone or a combination of the two should be offered to patients with one to four unresected brain metastases, except for the situation of small cell carcinoma, which has a different approach that's used often with prophylactic cranial irradiation. So, that's a separate group. But for others, SRS is the modality that should be offered.

And then for patients who underwent surgical resection of their brain metastases, we know that there needs to be some form of radiation treatment to the surgical cavity. And the recommendation was that SRS alone should be offered to those patients if the surgical cavity can be safely treated, and considering the extent of remaining intracranial disease. Obviously, for patients who have a lot of disease but otherwise have a treatable systemic disease, then whole brain radiotherapy may make more sense. But for the ones that are more limited after surgery, it should be SRS.

And then when the panel considered a situation where you have patients with more than four unresected metastases and the options included radiosurgery, whole brain radiotherapy, or radiosurgery plus whole brain radiotherapy-- and in general, these are reasonable options. But it was felt that SRS may be preferred for patients with better prognosis or where systemic therapy that is known to be active in the central nervous system is available.

Additional recommendations revolved around both protective, radioprotective, and radiosensitizing agents. So, in terms of trying to protect memory, there are two approaches that are used. One is to give memantine during whole brain radiotherapy, or to do whole brain radiotherapy using a hippocampal avoidance technique. And it was felt that either one of those or both should be offered to patients who will receive whole brain radiotherapy and have no tumors in the hippocampus, and they're expected to live more than four months. And then finally, that radiation sensitizing agents should not be offered to patients, because they've not been shown to be effective.

BRITTANY HARVEY: Understood. And it's helpful to know both what those recommendations are for specific approaches, and as you said, critical to know who will and who will not benefit from radiation therapy. So, then we've just reviewed the key surgery, systemic therapy, and radiation therapy recommendations. Dr. Schiff, did the panel recommend anything regarding the timing of surgery, radiation therapy, and systemic therapy?

MICHAEL VOGELBAUM: The panel had just a couple of points in this regard. Although there are some recent data suggesting a decreased incidence of leptomeningeal metastases in patients who undergo radiosurgery before craniotomy, as compared to the reverse sequence, the panel concluded no recommendation on this point regarding the specific sequence of therapy could be made. And to reiterate, for those circumstances in which systemic therapy may be of use for brain metastases, that therapy should proceed, local therapy like surgery or radiation, only if the brain metastases are asymptomatic.

BRITTANY HARVEY: Great. Thank you both for reviewing these recommendations. In your view, Dr. Vogelbaum, what is the importance of this guideline, and how will it impact clinicians?

MICHAEL VOGELBAUM: I think one of the important points that David raised that at the beginning was that this really is the most comprehensive look at the evidence revolving around the treatment of patients with brain metastases and leptomeningeal disease. And in particular, this may be new information for an audience that has not been involved in that treatment for many decades, the medical oncology community.

So, I think some of the impact on clinicians may be that the guidelines will help them understand the durability of surgery and radiosurgery, and those had been the only treatments available for a long time. And so now we have these new medical therapies that are showing activity in the brain, but one needs to balance that against what is known about the effective treatments in the past. Some of the new targeted immunotherapies may not provide as consistent or durable of a benefit as has been shown previously with surgery and radiotherapy.

Hopefully, understanding this challenge with respect to consistency and durability will serve to support the development of phase 0 or window of opportunity clinical trials to better understand the determinants the biological determinants of response or resistance to systemic therapies we want to improve on that, for sure, and those clinical trials are going to be essential for us to be able to do that.

And then ultimately, also, identify opportunities to synergistically combine radiation and medical therapies and better understand the timing of these combinations. This is a great area for clinical trial development in the future.

BRITTANY HARVEY: Definitely. We'll look forward to future research in those areas. So then, finally, Dr. Schiff, to wrap us up, how will these guideline recommendations affect patients?

DAVID SCHIFF: Yeah. Over the last 30 years, the management of brain metastases have involved hugely, from an area where almost everyone got whole brain radiation therapy and many patients died from their brain disease. The use of local therapies like surgical resection and radiosurgery has greatly improved local control of brain metastases. And with options like radiosurgery alone for a limited number of brain metastases, systemic therapies as the initial approach, and hippocampal avoidant whole brain radiation therapy with memantine, patients are experiencing improved long term cognitive function and quality of life, as well. So, I think the careful delineation of the role of each of these modalities that these guidelines provide will really help maximize benefit and minimize the risk for this very large number of cancer patients.

BRITTANY HARVEY: Definitely, improve quality of life is always a goal. So, I want to thank you both for your work on these guidelines and thank you for taking the time to speak with me today, Dr. Vogelbaum and Dr. Schiff.

DAVID SCHIFF: My pleasure.

MICHAEL VOGELBAUM: Thank you, Brittany.

BRITTANY HARVEY: And thank you to all of our listeners for tuning in to the ASCO Guidelines podcast series. To read the full guideline, go to www.asco.org/neurooncology guidelines. You can also find many of our guidelines and interactive resources in the free ASCO Guidelines app available in iTunes or the Google Play Store. If you have enjoyed what you've heard today, please rate and review the podcast and be sure to subscribe, so you never miss an episode.

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