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Improving Breast Cancer Radiation Treatments with Dr. Rachel Jimenez

By BCRF | February 29, 2024

Dr. Jimenez discusses a new strategy for delivering radiation that could reduce treatment time and minimize its damaging effects on the heart

Radiation therapy has long been a mainstay of breast cancer treatment for many patients. Like other areas of cancer care, the goal is always to reduce risk as much as possible while still maintaining benefits. For patients undergoing radiation therapy, one key risk is unintended radiation exposure. In cases of breast cancer that occur in the left breast, for example, unintended radiation exposure to the heart can increase the risk of heart failure. So how could doctors limit this kind of damage?

Enter Dr. Rachel Jimenez and her research on proton beam radiation. Unlike traditional radiation, proton therapy radiation can target cancer cells specifically, sparing other healthy tissues from potential damage. Additionally, as part of her Conquer Cancer Foundation Advanced Clinical Research Award for Diversity and Inclusion, Dr. Jimenez and her colleagues are exploring whether proton beam radiation therapy could be delivered effectively in a shorter time span than traditional radiation, cutting down on the disruption to patients’ lives.

Dr. Jimenez is an assistant professor of radiation oncology at Harvard Medical School and the chair for quality and safety in the department of radiation oncology at Massachusetts General Hospital. Dr. Jimenez also serves on multiple national committees in oncology as well as various professional societies and patient advocacy organizations.

Read the transcript below: 

Chris Riback: Dr. Jimenez, thank you for joining. I appreciate your time.

Dr. Rachel Jimenez: Thanks for having me.

Chris Riback: I thought we should start with your specialty: radiation oncology. Given the range of cancers, why did you choose to apply your specialty so significantly towards breast cancer? Why this discipline? Or by chance, do I have that wrong and you apply your time equally across all cancers?

Dr. Rachel Jimenez: You do have it right. So the majority of my time is spent caring for patients with breast cancer. And in the academic setting in which I practice that’s quite common. So academic physicians often will focus their practice on a specific type of cancer because it allows us to really delve deeply into the management of patients with that given cancer type. In my case, breast cancer. So we’re really thinking about how to care for those patients most carefully and are able to then lend our thoughts towards the creation of clinical trials and other types of research that we think are most likely to benefit those patients.

Chris Riback: And what drew you there?

Dr. Rachel Jimenez: As a trainee, as a resident, I really enjoyed caring for breast cancer patients. And while I enjoyed caring for many patients of many different types, I think the reason why I was drawn to breast cancer patients is because I feel like many of those patients are multi-hyphenate. They are mothers, they are wives, they are employees. They carry many, many different roles in their lives on top of managing their breast cancer and going through treatment. And I was really inspired by so many of the patients that I met, just seeing how many hats they wear despite the challenges. And it’s just a very inspiring group of patients to get to take care of.

Chris Riback: Which leads to my next question, which I wrote based on something I’ve read about you, but I feel maybe I chose slightly the wrong word. And my question is, what’s the role of compassion in what you do? And listening to you right now, maybe it’s not compassion, maybe it’s empathy, maybe it’s both. But in learning just a little bit about you, not a ton, it’s evident that that’s a key theme across who you are, how you engage with patients, how you think about your work. So tell me, if you would, how you think about compassion or empathy or any other word that you choose to throw in there?

Dr. Rachel Jimenez: Well, first of all, thank you. That’s very kind. I mean, I would like to think that all physicians go into medicine because they have an abiding empathy or compassion for the people that they care for. And I do think that it really is a privilege on our part to get to care for so many wonderful, impressive, steadfast, and dedicated patients. And I think that that’s the joy in what we get to do is to serve them in some small way on their journey to cure their cancer. So for me, I would like to think that that’s not a unique aspect of my practice, but I think it is the component of my practice that gives me the most satisfaction, which is really getting to know people as people—who they are, what they value, what’s important to them. And then be able to, again, in some small way care for them and to honor their values in the process.

Chris Riback: I love your use of the word dedicated, how dedicated the patients are. It’s such a multifaceted description and so accurate, and I haven’t heard it necessarily characterized that way, but it absolutely comes across in every conversation that I have with researchers, scientists, physicians, caregivers like you is the dedication. Because so many of the patients, yes, they are on a very, very challenging, to say the least, personal journey. And yet so many of them—and we’ll get to talk about this in a moment when we get into your clinical trials and your studies and your research—and I’ve heard it with other researchers, they are dedicated to the cause to other patients, to not just their journey so often, which has to be all-consuming, but also helping advance and discover and research for themselves but also for others.

That’s a really interesting and fantastic choice of words to describe their dedication, which it really is. It takes dedication to get through years of medical school and training, but it takes a different and really extreme type of dedication to be a patient. And that’s really thoughtful of you to recognize, of course.

Let’s move to the numbers. Approximately 60 percent, as I understand it, of breast cancer patients receive radiation therapy as part of their care. Why is that and how does that number compare historically? And I guess if I could pile on, in an age of increasing velocity of customized therapies and approaches to me as a lay person, an outsider, that 60 percent number feels high. So, talk to me about the 60 percent and how does it compare historically, please?

Dr. Rachel Jimenez: Sure. So the 60 percent may also be historical because we’re seeing so many advances in breast cancer therapy where we may be able to forego radiation, where patients don’t necessarily need to have radiation with a diagnosis of breast cancer. But to answer your question, historically, and I guess it depends on how far back we want to go, patients were treated quite radically even for very small early-stage breast cancers. And so many patients underwent mastectomy. And that mastectomy could be a fairly dramatic procedure with long-lasting morbidity for patients and cause a lot of side effects and really inhibit their quality of life.

And so there had been a number of clinical trials that explored the idea of instead of a radical mastectomy, doing a less aggressive procedure called the lumpectomy where we remove the cancer, but we preserve the breast of the breast tissue. And what we found was that adding radiation to the treatment, meaning delivering radiation to the intact breast after the patient had had the cancer removed, seemed to confer the same cure rates as doing a more radical mastectomy procedure.

So, when that data matured and we saw that the outcomes for those patients were just as good, the standard of care really began to limit the extent of surgery such that for early-stage breast cancer patients had a lumpectomy and radiation, and so they went hand in hand. That meant that many patients with early-stage breast cancer received radiotherapy. So, I think that’s where we’re getting that 60 percent number. And then there are other patients for whom the cancer may have left the breast but not traveled far away in the body, maybe into the lymph nodes underneath their arm, where they could still have curative surgery with a mastectomy and removal of some of those lymph nodes and might still benefit from radiation as a way to kill any small amounts of cancer that could be left behind even after a surgery like that.

So, the combination of both patients with early-stage breast cancer having a lumpectomy but preserving their breast and this other cohort of patients who may have still required a more aggressive surgery but could still benefit from radiation treatment afterwards gets us toward that 60 percent. Now, as I mentioned before, we’re starting to, I think, decrease that 60 percent number. There are patients who, as we learn more about breast cancer, have not very aggressive breast cancers. And so they may be adequately cured with surgery and some medication alone and they might not need to have radiation. And so now we’re seeing that older patients, patients with small cancers that are very favorable in their tumor biology, might be able to safely forego radiation treatment with still excellent cure rates.

Chris Riback: What is proton beam radiation?

Dr. Rachel Jimenez: Proton therapy is a type of radiotherapy. Typically, when we use radiation as a way to cure cancer, we’re using X-rays. And so those X-rays are the same X-rays that a patient might get when they go to the dentist and get an X-ray or when they have some other type of imaging if they break a bone. But we’re using the X-rays in a different manner. We’re using them at a higher energy as a way to damage the DNA of the cancer cell and prevent that cancer cell from growing.

With proton therapy, instead of using X-rays we’re actually accelerating subatomic particles called protons. And so those protons have a different physical property. The beam of the radiation behaves differently than X-rays do. And so the potential benefits of proton therapy is that we might be able to direct the radiation at the area that we think could be harboring cancer and that the radiation beam would stop after it treats that particular area, it doesn’t continue to travel through the rest of the body. This means that we’d be able to spare some normal tissue from getting exposed to radiation when we wouldn’t intend to give radiation to that area. But where X-ray therapy might still deliver X-rays, again, not intentionally, but because of the property of the X-ray that it may continue to travel through the body.

Chris Riback: And do I understand correctly, some of the tissue that people like you worry and have worried about with the X-ray form, let’s say, of radiation is particular to the heart? Is that correct?

Dr. Rachel Jimenez: That’s right. So for patients who have breast cancer, we’re always thinking about what are the parts of the body that are near the breast that might inadvertently get radiation that we don’t want to give radiation to? And so the heart is one of those.

The reason is because historically with radiation, we didn’t really have as many tools as we have available to us now. When we planned radiotherapy, it was pretty crude. So we would deliver the X-rays to the best of our ability using pretty limited anatomic knowledge of where things were in space. We could see the breast, but we really couldn’t see internally to understand where the heart was in relation to the breast. And in that era when we were delivering radiation in that manner, we saw that low doses of radiation to the heart did translate into a higher risk of heart disease for patients as they age. So we were curing breast cancer, but then we were finding that those patients were more susceptible to heart attacks and other things later. We were accomplishing the exact opposite thing of what we were trying to do, which is cure these patients and give them a great quality of life as they got older.

Now we have a lot more techniques that are available to us where we can visualize the internal parts of people’s bodies and see where their hearts and lungs are in relation to their breast. And we do that using CAT scans. And so most radiation planning these days uses a CAT scan so that we can actually see inside and try to avoid exposure of the heart and the lungs when we deliver the radiation. But there are some patients for whom even when we can see where everything is, there are some limitations to the technological delivery of the radiation that would still confer some radiation delivery to the heart and the lungs even when we didn’t want to, just because the techniques are limited to some degree. If the heart’s really close to the breast or to where the cancer is, it’s hard to avoid treating some of the heart with radiation.

So the potential benefits of proton therapy are that we might be able to better spare the heart, even in patients who have cancers where that is located very close to the heart. And so, I think that there’s a lot of interest and excitement about the ability to again, preserve the health of many of these patients who, aside from their cancer, are very healthy people that we’d like to see have great quality of life for many decades after we cure their cancer. And proton therapy may be a way to achieve that.

Chris Riback: There certainly is a lot of excitement around it. And some of that excitement is translated or has been translated into, I believe, funding or at least some type of support for a study that you and your team are undertaking. Tell me about the study around proton therapy. How will you do it? What will the research look like? What’s the current status?

Dr. Rachel Jimenez: Sure. I’ve been very fortunate that BCRF has funded the study that we’re looking at. My interests from a research perspective are always in trying to make treatments less burdensome and safer for patients. This particular study is really looking at both of those things together.

Just to provide a little bit of context, when patients receive radiation for breast cancer, often those patients that receive treatment need to have treatment daily Monday through Friday for a period of weeks. And again, historically it used to be that many patients required between five and seven weeks of daily radiation, which if you have a job and you have a family and you have other obligations can be quite burdensome. And radiation therapy is not something that we can just strap onto our back and bring to your door. So patients have to drive to a facility that has that capability, which means that many patients are driving quite a distance every day for multiple weeks to receive treatment.

So there has been a change over the last few decades to try to move towards shorter, more compressed treatment schedules for patients so that they don’t need to come in for such an extended period of time. That we could deliver radiation instead of over six or seven weeks that we could deliver that same radiation course over three to four weeks. And so we’ve seen that the treatment schedules have gotten shorter, which is much more convenient for patients. And so then the question becomes, how short can we go? How few treatments can we actually achieve safely?

So there has been a lot of interest in a one-week treatment schedule, and this has been explored in some large randomized clinical trials for early-stage breast cancer where they have found the same great local control rates, the same cure rates in these patients, and the same side effect rates in patients using a very compressed schedule over one week instead of these longer courses of treatment. So I think that is a big win for patients. And certainly if I were a patient and I had breast cancer, I’d like to think that I could get my cancer treated in one week and have minimal disruption to the rest of my life compared to having to commit to six or seven weeks.

And so in this particular study, what we’re doing is exploring this one-week regimen of treatment for patients who require breast radiotherapy, specifically those who require left-sided breast radiotherapy, where we’re worried about the heart. And we’re comparing proton therapy as we talked about and those potential benefits with regular radiation. We’re trying to determine if patients who receive proton therapy show less damage to the heart or less changes to the heart compared to those patients who receive regular radiation.

Chris Riback: And one, what’s the status of the study? I believe you might be in the stage where you’re securing patients, but maybe you’ve advanced beyond that. And two, for the older form of radiation, is the potential damage or when the damage does occur to the heart, is that evident immediately? Or when you’re doing this study, are you going to have to wait X years to see in column A, did the old form create damage and the new form did not?

Dr. Rachel Jimenez: Great question. So for most patients who have radiation, side effects do not appear right away. And so that’s been a real challenge for us because if radiation therapy is causing damage to the heart, but we don’t know it for 10 or 20 years, then it becomes very difficult to be proactive in caring for those patients and in telling patients very transparently when they get treatment what the real risks are to them. So we can look at a population of patients in a study and say, X number of patients have heart disease, but that doesn’t matter to the person in front of you. They want to know if that’s going to happen to them and what they need to do to take care of themselves.

So in this particular study, we’re utilizing an advanced cardiac imaging technique. We’re using a cardiac MRI. Looking at patient’s hearts with a cardiac MRI allows us to see if there are any subtle changes to the heart—things that we wouldn’t be able to pick up just by looking at someone or examining them in our office that would confer to us that this patient might have an increased risk later of a cardiac event.

And so using this kind of imaging gives us a tip-off that this is a patient that we should be thinking about more proactively and caring for more proactively from a cardiac perspective. And I’m excited about this because I think that oftentimes as radiation oncologists we sit on our hands and wait for side effects to happen. But what’s really compelling about being able to study patients in this manner is that we don’t have to wait, that we can actually communicate to patients that we don’t know for sure if you’re a patient who will have a cardiac event, but we can see on your imaging that you have some changes, and this makes us want to be more proactive about your survivorship care.

Chris Riback: Yes, I would assume that it’s fantastic for you in your role to know that, and it’s central to the patient and in their situation to know that. And so where are you in the study right now?

Dr. Rachel Jimenez: So we are actively accruing patients to this study. We’ve accrued about a quarter of the patients so far. It seems to be quite a popular study for reasons that I think we’ve spelled out, which is that patients are looking for ways to make treatment more convenient and safer for them. And so I’m excited to see how the rest of the accrual goes and to encourage our patients to think about participating if it’s something that has interest to them.

Chris Riback: How did you get into this? Let’s talk about you a little bit. I mean, going way back, where did you grow up? For you was it always science or were you this close to being an English professor?

Dr. Rachel Jimenez: Not super close to being an English professor. I grew up in Connecticut. My mom is a nurse, and I think the idea of taking care of patients was very present when I was a small kid. My mom was a pediatric nurse, and we used to spend time in the hospital with other kids who were hospitalized and didn’t have visitors. Sometimes she would bring kids to our home if they didn’t have family situations where people were visiting them. So from a young age, I really seemed to absorb from her the importance of caring for patients in a very personal way.

And while I did not know that I was going to be a doctor right away—it took me some time to figure that out—I think that I always was very interested in and engaged with people and what they valued and what was important to them. And I think cancer care has a very special way of providing that relationship between patient and physician. What patients go through is such a life-changing event. And so again, it’s such a privilege as a physician who’s caring for them in that context to be on that journey with them, to serve them in that way. And so I think cancer care really stood out for me pretty quickly when I started medical school. And I still believe that it is the best specialty and the one that I feel just truly privileged to get to be a part of.

Chris Riback: Well, obviously the compassion gene does not fall far from the tree. Is your mother still alive?

Dr. Rachel Jimenez: She is. Yep. She’s retired now.

Chris Riback: She’s retired now. Well, we need her back. What does she say about what you do?

Dr. Rachel Jimenez: Obviously, I think she’s proud of me. She’s proud of all her kids. And I think that it probably makes her feel some level of satisfaction to see that the field that she was so dedicated to for so long is something that continues in the next generation. I think that my family has had their own experiences with cancer over the years. My dad is a cancer survivor. Many of my family members are cancer survivors. And so I think that that adds an extra connection to cancer care, even though that was not her focus when she was in medicine.

Chris Riback: There’s one other area, if I’ve read about you correctly that I believe another aspect of cancer care—indeed medical care—that I believe is of interest to you, which is cultural diversity. Why are you focused there? What does it mean to you, and what actions or behaviors does it inspire?

Dr. Rachel Jimenez: I think from a cultural diversity standpoint, I am the product of cultural diversity. I come from a family that has roots and backgrounds in many places. And so I think that from a young age I knew or was aware of ways in which I was a bit different from other people in my community just based on my cultural, ethnic, and religious background. Coming from a family that is so rich in diversity, I think that I see not only myself reflected in conversations about diversity but also just recognize the value of different perspectives, different walks of life, different life exposures, and how important it is to honor those things and promote those things in medicine.

So my patient population tends to be relatively diverse in Boston, and I’m very gratified by that. I think it makes me very happy to see people from all different backgrounds and walks of life come through the door and make sure that when we are caring for them, we’re caring for them as well as we possibly can regardless of their circumstances in life. And I know that there’s been a lot of attention paid in medicine to reducing those disparities across the board, and I feel very passionately about doing my part to do the same.

Chris Riback: You certainly are doing that, it’s evident. To close out, I know you touched on it briefly before, but what role has BCRF played in your research?

Dr. Rachel Jimenez: I am just incredibly, incredibly grateful to BCRF because the research that we’ve talked about simply would not have been possible without them. I think one of the really special parts of BCRF is that they fund research that might not be readily fundable through other mechanisms simply because of the study design or the type of question that not all study sponsors would be supportive of that kind of work. So I’m just incredibly gratified that BCRF saw the value of this research and was willing to support it because it makes all of the difference, not just for me, but potentially for the advances that we can offer patients.

Chris Riback: Yes, I’m certain that it does. And Dr. Jimenez, thank you. Thank you for your time, of course. Thank you for the work that you do, the compassion, the empathy, but also the imagination and the care that it’s so evident that you give. Thank you.

Dr. Rachel Jimenez: Thanks so much, Chris. I appreciate it.