The Evolution of Breast Cancer Radiation

Podcast Transcript

Dale Shepard, MD, PhD: Cancer Advances, a Cleveland Clinic podcast for medical professionals, exploring the latest, innovative research and clinical advances in the field of oncology. Thank you for joining us for another episode of Cancer Advances. I'm your host, Dr. Dale Shepard, a medical oncologist here at Cleveland Clinic overseeing our Taussig Phase I and Sarcoma programs.  Today, I'm happy to be joined by Dr. Chirag Shah. Chirag is the Director of Breast Radiation and Clinical Research in the Department of Radiation Oncology here at Cleveland Clinic. He's talking to me today about the radiation of breast cancer. Welcome Chirag.

Chirag Shah, MD: Good morning, Dr. Shepard.

Dale Shepard, MD, PhD: So Chirag, Maybe you can start by just telling us a little bit about your role here at Cleveland Clinic.

Chirag Shah, MD: Sure. So as the Director of Breast Radiation Oncology, my first role is to take care of women with breast cancer and at the same time to advance our clinical breast cancer program with respect to developing new radiation therapy techniques that improve outcomes and reduce side effects. As the Director of Clinical Research for the Department of Radiation Oncology, I work with our research team to open novel clinical trials so that we can offer each patient that comes through our doors, a new clinical trial to look at.

Dale Shepard, MD, PhD: So, I mean, just as a backdrop, how has radiation for the breast changed over the past decade?

Chirag Shah, MD: So radiation therapy for breast cancer has completely changed since 10 years ago. So I was starting my practice 10 years ago, and basically most women who came into my door were told that they needed five weeks of radiation at a minimum. And that was that. There were very few, if any alternatives to that. Fast forward to today, and there are at least four or five options for almost every patient. So for early stage breast cancer patients, we're starting to use tumor genetics and new factors to identify women who don't need radiation at all. We offer short course radiation that completes whole breast radiation in three weeks. And over the past few years, we've really increased our role in using partial breast radiation, which completes radiation in one week or less in many cases. For locally advanced breast cancer, we've gone from five to seven weeks to three to four weeks, and also using different factors to identify the patients that are best suited in getting radiation therapy.

Dale Shepard, MD, PhD: And so we'll talk a little bit about some of these specifics, but has this been more of an impact in patients who are getting radiation therapy prior to surgery? After surgery? A little of both? What does that look like?

Chirag Shah, MD: So by and large, radiation therapy in breast cancer is delivered after surgery. So all of these are patients getting radiation after surgery. There has been an evolving role over the past decade in using radiation before surgery, in conjunction with some chemotherapies, for patients who have unresectable breast cancer, but that does represent a minority of our patient population.

Dale Shepard, MD, PhD: And do you think that's likely to remain the case?

Chirag Shah, MD: I think so, for the most part, there are some really novel trials looking at giving a single dose of preoperative radiation before surgery and then performing surgery within a few days or a few weeks of that single treatment of radiation. But I imagine it'll be five or ten years before we have outcomes from those studies.

Dale Shepard, MD, PhD: And for perspective, how many patients are we talking about? So breast cancer is a very common cancer. How many women does this affect?

Chirag Shah, MD: So breast cancer is the most common non-cutaneous or non-skin cancer in women in the United States. So more than 250,000 new cases are diagnosed each year. So this really is a huge incidence cancer and one that affects basically almost everyone in some way.

Dale Shepard, MD, PhD: So you mentioned a number of different approaches and here at Cleveland Clinic, how do we approach which patient is best suited for which type of radiation?

Chirag Shah, MD: I think that's a great question. And it's one, I think that every breast oncologist struggles with. And so I think the first thing that we do is we talk about having each of those options available to our patients. So we have interoperative radiation technology, we have partial breast technology, we have whole breast technology. So we have the equipment and the expertise to deliver each of those. The next is a really important discussion, the multidisciplinary discussion between the breast surgeon, the breast oncologist and the breast radiation oncologist, where we look at the patient as an individual and look at their treatment characteristics, their pathologic characteristics to decide which options are available. And then the final part of that is really informed decision making with the patient, talking about the different options that are appropriate based on their cancer, and then coming to a decision that meets their needs for cancer treatment, as well as goals of care.

Dale Shepard, MD, PhD: What would be some of the primary things that would lead you into one direction or the other? Is it age or comorbidities or what kind of factors do we consider most?

Chirag Shah, MD: So when we look at early stage breast cancers and we talk about omitting radiation, the factors we look at, for example, include age, age over 65 or age over 70. Small breast cancers, typically T1s, less than two centimeters, no negative cancers that respond to estrogen. Those are the kinds of patients that we think about omitting radiation in or in low risk patients offering things like interoperative radiation to. When it comes to partial breast radiation, we tend to think of women, 50 years or older with estrogen positive cancers that are two to three centimeters that are node negative. And then routinely for early stage breast cancers now all patients are eligible for short course, whole breast radiation. When it comes to locally advanced cancers, age is a factor, but also the type of surgery they choose, whether they choose lumpectomy, mastectomy, or mastectomy with reconstruction, as well as their lymph node status.

Dale Shepard, MD, PhD: You mentioned something about tumor genetics and more histology or genetics based therapies. And that certainly have been ... It's really over the systemic therapy landscape. So how has that sort of been incorporated into radiation of the breast and what are some of the things that have developed recently in that arena?

Chirag Shah, MD: Tumor genetics has become a mainstay in breast oncology in terms of helping to decide upon systemic therapy treatments. With respect to radiation, we're kind of in the early stages of doing this. And so we break those tests up into two areas. So the first is stage zero or DCIS cancers. And there's really been a series of tests that have emerged that have looked to stratify patients based on their tumor genetic profile, into needing radiation or not needing radiation. And so that can include a Oncotype DCIS test or a decision RT test, which are both on the market right now. And what they do is they allow the patient and the clinician to talk about their individualized risk and then their potential benefit from radiation therapy. And then at that point, it allows for informed decision making.

On the locally advanced side, there are still trials underway, but some preliminary work has shown a nice correlation between Oncotype and local regional recurrence. So in patients who were not absolutely certain whether or not the patient would benefit from radiation, we're starting to at least consider that test as part of the decision making for patients.

Dale Shepard, MD, PhD: And I guess, one of the considerations we have on the chemotherapy side and on the systemic therapy side is coverage for some of these tests. Is this something that patients who could benefit from these genetic tests would normally have them available by insurance?

Chirag Shah, MD: Yeah, it's an important question. So on the invasive side, many of the studies are using the same Oncotype that our medical oncologists are ordering. So in that sense, it's nice because it's a test that works for both sides and typically is covered. For the DCIS tests, we're starting to see more coverage and therefore more access to patients, but there's still more data coming out so that it's available for all patients.

Dale Shepard, MD, PhD: You mentioned before about some of the trials that are going on. Tell us a little bit about some radiation trials that are happening in breast cancer here at Cleveland Clinic.

Chirag Shah, MD: It's a great question. So we have several really great innovative trials underway right now. So the first of those trials is a study looking at a new way to target radiation. It's using a radio opaque marker that's placed in at the time of surgery to allow for advanced targeting of breast radiation, to minimize treatment to other organs or the rest of the breast. And that's being done in conjunction with our breast surgical program.

We're also doing a study where we look at the bacterial composition of the skin of the breast, taking skin swabs of the breast and looking and seeing how that correlates with breast side effects. Seeing if the bacterial composition of the skin will impact those side effects. In terms of other studies, we're a participant in several national trials, including studies at the omission of radiation in women who have great responses to chemotherapy prior to surgery. As well as looking at trials, looking to shorten the course of radiation and women who are undergoing mastectomy with reconstruction.

Dale Shepard, MD, PhD: I guess, just to elaborate a little bit with the targeting therapies, is this really more to minimize the exposure to normal tissue to account for movement? Or what is this going to be most helpful for?

Chirag Shah, MD: It's really most helpful to try to limit side effects. And by limiting movement, we're able to limit how much normal tissue we treat, and so therefore we're able to reduce our margins and if we can reduce our margins, that means reducing the amount of normal tissue and therefore side effects. That's really the penultimate goal of the targeting strategies is to really better identify the target, better control for motion and therefore reduce normal tissue that's treated in side effects.

Dale Shepard, MD, PhD: I guess certainly both are important. So efficacy, toxicity, what do you think within radiation of the breast is going to be, really make the biggest impact and being able to improve efficacy or minimize toxicity? They kind of go hand in hand, but what do you think?

Chirag Shah, MD: So, I think to be honest, with early stage breast cancers, we've gotten local recurrence rates very low. So a recent randomized trial that was published, showed 10 year recurrence rates at 4% in the breast, which when I started my career, I think was unheard of. So I think we've really gotten quite far in advancing outcomes with respect to radiation and local control.

I think the next step is taking those outcomes and finding ways to reduce the side effect profile. By doing that, I feel like we're able to increase the therapeutic ratio and really the difference between outcomes and side effects. So I think my expectations in the years to come are one, we're going to come up with better techniques to reduce side effects. But also use the patient's individualized tumor genetics to pick out the patients who don't need radiation at all, who are going to have those great outcomes without needing the extra treatment.

Dale Shepard, MD, PhD: When we sort of think ahead, are there any new techniques that are maybe still under investigation that you're most sort of eager to find out the results for? Is there anything sort of potentially practice changing that you kind of have your eye on, looking for results?

Chirag Shah, MD: Yeah, so I think the biggest thing we've been looking at for the last 10 years is kind of that concept of partial breast radiation versus whole breast radiation. And that has a really kind of started to answer itself now in the past a year or so. And so we've had major randomized trials from cooperative groups, as well as an analysis from our own institution, which have really supported that partial breast and whole breast are comparable with respect to outcomes and may even offer a reduced side effect profiles. In terms of what we're looking forward to in the years to come, I think the biggest thing you're going to see as an evolution of treatment techniques. So as I said, minimizing motion, improved targeting, to reduce dose to the heart and lungs and also strategies to reduce lymphedema that's associated with radiation therapy.

Dale Shepard, MD, PhD: So when you talk about partial breast radiation, it sort of reminds me of mastectomy versus lumpectomy. Who do you think is going to need the most convincing for this kind of approach? The docs or the patients? Sort of this concept, maybe more is more and not less is more.

Chirag Shah, MD: It's a great question. And to be honest, I would say it's probably the docs. I think patients when offered this option, by and large, choose this option. The idea of treating less and seeing less side effects, I think is very pragmatic to patients in the sense that they say, oh, you're not treating my whole breast. So I'll have less side effects. I think physicians have been appropriately more cautious in jumping into doing partial breasts, but I think we're seeing that evolution now, now with multiple randomized trials reporting 10 year outcomes with comparisons.

Dale Shepard, MD, PhD: And I guess some of these sort of differing ways to deliver therapy. When I talk to patients, realize that some of our radiation techniques are pretty specialized. Are there differences between academic medical centers, community practices? What do you think are the biggest differences in the radiation of the breast area?

Chirag Shah, MD: It's an important question. And I try not to kind of say it's an academic or a community practice. I think it's about asking what each center has in terms of technologies and availabilities. So for example, at our main campus, we have a linear accelerator where we really have dedicated the focus to breast radiation and heart and lung sparing breast radiation. And that's a certain level of specialization. That being said, our regional practices are all using heart sparing techniques and offering that to patients so that they're getting the best care possible, wherever they're being treated. In terms of partial breast techniques, I think that is something that we see a differentiation in that larger centers tend to practice more partial breast radiation in my experience. But that being said, there are practices throughout the region, as well as outside of the state that are using partial breast routinely.

Dale Shepard, MD, PhD: So I guess what guidance would you provide? This is a physician audience. When people should think about getting referrals, either for opinions on treatments or treatment itself?

Chirag Shah, MD: So, I mean, I think one of the things I always recommend is that every cancer is individualized and unique. And so I often will have patients or even physicians reach out to me for what would be considered an early stage breast cancer, because there may be techniques or options available that are not available at their center. So I would say even if it's just reaching out for an opinion, it's always possible to reach out for that, whether it be early stage or locally advanced. And then in terms of techniques, things that I think are really important include asking about heart and lung sparing techniques that are available and ways to shorten the course of radiation therapy for patients.

Dale Shepard, MD, PhD: And I guess you mentioned heart, and we certainly we have a lot of multidisciplinary care here. How does that get incorporated into radiation for the breast?

Chirag Shah, MD: I think that's a part of everything that we do. So, obviously when patients come, they see a multidisciplinary team and one of the things that we focus on and specialize on is making sure that patients get access to, for example, cardiac oncology or cardiologists that are specialized in treating cancer patients. As well as really thinking about how we can risk stratify patients so that we can take patients who may be at risk of heart conditions and thinking about their treatment plans more holistically, incorporating that into their care.

Dale Shepard, MD, PhD: It's very important. So Chirag, you've had some great insights. Are there any other additional thoughts or comments or things that we need to know about for radiation?

Chirag Shah, MD: I would say that radiation and radiation therapy for breast cancer is a very rapidly evolving field. And I think one of the things I tell colleagues both at this institution and elsewhere is that, don't close your eyes because breast radiation is probably going to change by the time you open them again. So I think it's one of those things where we have to stay attuned to the literature and the trials and see where things take us.

Dale Shepard, MD, PhD: Excellent. Well, Chirag, thank you very much for joining me today.

Chirag Shah, MD: Thank you so much. Have a great day.

Dale Shepard, MD, PhD: This concludes this episode of Cancer Advances. You will find additional podcast episodes on our website, clevelandclinic.org/canceradvancespodcast. Subscribe to the podcast on iTunes, Google Play, Spotify, SoundCloud or wherever you listen to podcasts. And don't forget you can access real time updates from Cleveland Clinics Cancer Center experts on our Consult QD website at consultqd.clevelandclinic.org/cancer. Thank you for listening. Please join us again soon.