Transcription:
Radiation Therapy – What’s It All About?

Dr. John Leonard (Host): Welcome to Weill Cornell Medicine CancerCast, Conversations About New Developments in Medicine, Cancer Care and Research. I’m your host, Dr. John Leonard. And today, our topic is Radiation Therapy, What’s It All About. I’m very happy today to have my friend and colleague Dr. Himanshu Nagar who is a board-certified radiation oncologist here at Weill Cornell and New York Presbyterian Hospital. He specializes in caring for patients with blood cancers and genitourinary malignancies including prostate, kidney and bladder cancers. Dr. Nagar is actively involved in developing clinical trials at Weill Cornell Medicine and at the national level, as a member of the Alliance for Clinical Trials in Oncology, Genitourinary Committee. That’s a major national cooperative group of the National Cancer Institute.

Dr. Nagar’s research interests include the use of functional and molecular imaging as well as tissue based and blood based biomarkers to personalize therapy and monitor treatment resistance. So, it’s really great to have you here today. Thank you for joining us.

Himanshu Nagar, MD (Guest): Thank you for having me. It’s an extreme pleasure.

Host: Radiation is part of day to day life at some level, because it’s in the atmosphere, we are exposed to it all the time. It has good connotations, bad connotations, all over the place. So, maybe if you can start by just giving us a sense at a high level of what is radiation in the context of cancer therapy?

Dr. Nagar: Generally speaking, radiation is energy like you mentioned. We are surrounded by it whether we are on the beach or we are in a plane, we are exposed to radiation all the time. The way it’s used in a medical context is that the energy behind the radiation is used to destroy cancer cells. So, it’s leveraging high energy sources to treat cancer versus the lower doses of energy or radiation that we are surrounded by all the time. So, it’s leveraging the physics of radiation therapy.

Host: So, is it a matter of dose, is it a matter of type of radiation, is it a matter of where you are aiming it, is it all the above?

Dr. Nagar: It’s all of the above. And we study dose effects, not just the total dose but the dose per sessions of radiation. Can you deliver the radiation all at once? Or do you need to space it out from day to day or week to week or month to month? So, it really depends both on the cancer type and the way we are trying to treat that cancer and more importantly what the eventual goals of that therapy are.

Host: So, when you talk about treating cancer and obviously as mentioned, radiation is used to treat many different types of cancer and different contexts. Tell us a little bit about kind of the principles of how you use radiation to treat cancer but walk us through that a little bit.

Dr. Nagar: Sure, so like any type of medical care, the first question to answer is what’s the goal of this therapy. So, are we doing it to cure the cancer? Are we doing it as an adjuvant or in addition to some other therapy or is it in a palliative role to treat a symptom? Once we decide on the goal of that therapy, then we decide what’s the tumor site, what’s the surrounding area for that tumor site and then appropriately so define what we are targeting and what we are trying to avoid. And from that, obviously, the dose that is needed to do that. It’s very patient-dependent and very tumor site dependent and the goal of therapy.

Host: So, what’s the most common kind of type of treatment that a patient is going to get from the standpoint at a high level from radiation treatment? I would presume that some of the more common types are breast radiation treatment, prostate radiation treatment. I’m sure there are others. What are in the big picture, the kind of the main kind of types that a patient would be considered for in most situations in a broad sense?

Dr. Nagar: Right. So, in a broad sense, it’s external beam radiation. So, roughly speaking, in this category, there is internal versus external radiation. The large majority of patients would receive external beam radiation where we are not implanting anything into the body, but we are using a machine with an x-ray source to treat that cancer from outside the body.

Host: Okay. And so, how has that evolved over time. I would assume that and just from my own reading of historical information, I mean it’s probably gone from a very imprecise to precise process. How has that gotten better? Is it just the machines are better, the physics of understanding? Is it computerized and therefore all of that’s much more precisely done? How does that work?

Dr. Nagar: All of the above. And so, the machines have definitely become more advanced and more sophisticated. Our planning techniques, so in the past, our imaging modalities and planning techniques would treat the tumor and quite a bit of surrounding tissue and now we are able to shape the beam in what’s called beam modulations. So, as the radiation is being delivered, it’s being delivered with the higher dose to the tumor and lower dose to other areas. So, it’s just the positioning that we have on the patients, the technology from the machine and the algorithms that allow us to shape the beam better and deliver the radiation dose more effectively.

Host: So, patients are very familiar with getting, and it’s not therapeutic radiation but diagnostic radiation if they get a chest x-ray, if they get a CAT scan or a PET scan. How is the radiation different in this particular situation?

Dr. Nagar: Exactly. So, as we were speaking about before, we are surrounded by radiation. The radiation we are surrounded by is very low energy radiation. For diagnostic purposes, it’s slightly higher radiation, but it’s not looking to damage cancer cells. In radiation oncology, we are leveraging much more energy and much more powerful radiation and therefore we have to be careful to treat only the tumor or the cancer and protect the normal tissue around it. So, it’s leveraging higher energy radiation for cell damage versus diagnostic radiation.

Host: What determines whether radiation is something that’s appropriate to consider for a given cancer and obviously, there are many factors that go into that. And then within an individual patient, how is that decision made within those cancers? 

Dr. Nagar: So, radiation has a long history since its discovery in 1895. And the first therapy for cancer including surgery or radiation. And since then as we’ve expanded the field to allow for systemic therapy and other ways to treat cancer; radiation has been studied across disease types. What radiation oncologists do very well is study disease and decide whether or not radiation can be omitted in that case and then also decide on if the dose needs to be higher or lower. So, it’s very individualized per patient and cancer type and studying patients, thousands of patients in clinical trials to determine what the benefit is and how great that benefit is.

So, a patient with breast cancer may elect for a mastectomy and that may or may not require radiation depending upon the tumor type, the spread of the cancer regionally or they might elect for a lumpectomy in a breast conserving therapy and that generally requires postoperative radiation to sterilize the tumor bed. In prostate cancer, patients for the definitive therapy could either elect for surgery or radiation as the primary therapy, the curative therapy. Even with patients that receive prostate surgery and have the prostate removed, there is still a role for postoperative radiotherapy if there is a recurrence.

So, it’s very dependent upon their tumor type and what the goal of that treatment is for a patient. It also depends on what is the goal of that treatment meaning are we going for a cure, are we going for palliation. So, it’s important to have that patient discussion with your radiation oncologist.

Host: So, in general, it seems like radiation is typically used in a setting where the disease is more localized, where you can aim it in a defined area and that defined area is reasonable so to speak. I mean with stem cell transplants and things, people may get total body radiation but for the most part, we are talking about local disease where one is choosing or there’s a benefit to radiation delivered to that local area versus surgery in that local area in many situations. Is that kind of a fair way to put it?

Dr. Nagar: Exactly and what I like to tell patients is that radiation is something in between surgery and medicine because radiation should be considered a medical drug because we are delivering a therapeutic agent to a specific area. But unlike surgery, we are not removing 8it, but we are still focusing as with surgical precision is the goal. So, it’s a combination and to understand that it’s a little bit both surgery and medicine and to think of radiation as a drug that’s being delivered to treat a cancer.

Host: So, in most cases where patients in the situation of choosing between radiation and something else, and maybe this is hard to generalize; is it more that the radiation or the alternative is more effective or is it just the different side effect profile?

Dr. Nagar: Generally, it’s the different side effect profile because we’ve labored as a cancer field to study different modalities, once versus the other. If there was a more effective treatment regimen, there would be no way to recommend the other treatment regimen in most cases. So, when we balance the therapy of radiation versus another type of therapy, it’s generally balancing the side effects and what that patient is willing to undergo.

Host: So, the definition of the treatment that a patient is going to get depends on what sorts of factors and how you define the exact doses. People have different sized tumors, different types of tumors. What’s kind of the way that that is sorted through and prescribed so to speak. It’s not only a drug analogy, obviously.

Dr. Nagar: It’s a radiation prescription.

Host: Right, so how does that all get set up and laid out?

Dr. Nagar: Right so, first a lot of it depends on the tumor type. Because we have tumors that are exquisitely what are considered radiosensitive versus radioresistant. And your savvy listeners will know, a radioresistant tumor generally requires more radiation. So the tumor type really does matter. Then it’s the setting in which the radiation is delivered. Is it to treat the tumor itself or has the tumor been removed and now radiation is looking to sterilize the tumor bed. And then the dose is very dependent upon that also. Having studies in clinical trials, which dose is appropriate and are we using it within adjunct therapy.

So, for example, head and neck cancer that has – is also treated with chemotherapy that sensitizes the tumor to radiation, so we do not have to deliver as much radiation for that cancer and it has shown to actually improve survival for that patient. So, it’s very tumor dependent and in what setting you are delivering that radiation to determine what’s being irradiated and what dose you need to irradiate with.

Host: So, having passed through the radiation oncology department a few times myself, not to receive radiation but to see what’s going on or to check on patients; it’s clear to me that there’s a lot of technology, there are a lot of machines, there’s a very big process and a lot happening. So, how would you inform say a patient who is going for a consultation or who is getting ready to start treatment; what’s the process, how does all of that work? I presume it’s not you and your laptop and a lightbulb obviously. It’s much, much more complicated than that and very sophisticated. But so that could potentially be intimidating to people also. So, kind of walk us through that process a little bit.

Dr. Nagar: Right, so the first step is the consultation where you meet with your radiation oncologist and understand why you have been referred to a radiation oncologist, what the goal of that therapy is and how that therapy will proceed. We discuss the role of radiation and the side effects that may or may not happen. Once your recommended to radiation and the patient agrees to undergo treatment, we bring them back to the department for what’s called a planning scan or a simulation scan. This can be performed with a CAT scan, a PET scan, an MRI scan and at that point, that allows us to begin the radiation planning.

This takes a large team. The patient sometimes just sees the MD, the physician at first, but it takes a group dosimetrists; that’s what they do, they deliver the dose or plan the dose. Physicists to check the plans and they see nurses and then actual therapist. So, while the patient’s not in the department after that simulation, that planning scan, a lot of work is being done in the background to plan the most effective radiation for that patient and their tumor.

And then they will come back and then treatment could be one day, five days, 20 days. It’s very dependent upon that patient and that patient’s tumor type. But a lot of planning goes into the process itself and it’s not just the physician that’s doing the work.

Host: So, the patient is going to, in the simulation is that kind of like getting a CAT scan?

Dr. Nagar: Exactly. It’s getting a CAT scan. During that simulation, we are positioning the patient, so they are in the correct treatment position each day because the one thing we want to ensure is that we have reproducibility for each treatment. We have different techniques to make sure that the patient’s immobilized for the right cancer types. So, a patient with head and neck cancer might have a mask made for their head and neck in order to stabilize them. We have molds for the lower half of the body. We have other what I like to call cool tricks to prevent the tumor from moving so the patient might hold their breath while the treatment is going on which leverages the physics of our body to deliver the radiation better and spare normal organs.

So, a lot of those techniques are implemented during the simulation or planning scan and we want that scan to be reflective of each of the treatments that you are going to receive.

Host: So, basically, this is all engineered around aiming the beam at the tumor as well as possible without getting in the neighborhood of the normal tissues in the body around the tumor.

Dr. Nagar: Exactly. We are trying to aim the beam with millimeters of precision in order to treat the tumor adequately but spare the surrounding normal tissue.

Host: Okay and so when a patient is on treatment and they go through several days and I guess is it a fixed dose per day and therefore bigger dose more days and what’s kind of the day to day sort of procedure, how long is a patient there, what do they just expect as they do that?

Dr. Nagar: Generally speaking, it’s the same dose per day. I tell patients it’s about two units of radiation per day and it’s a cumulative dose depending upon the patient’s tumor type as to what the total dose needs to be. The patient experience itself is they are laying on a treatment table and the machine treats their tumor by encircling their entire body from different radiation angles. Generally, patients don’t feel anything. It’s x-rays. You are not going to feel anything during the treatment itself. And then the patient leaves the department soon after that.

We tell patients in and out coming to the department about an hour. The treatment itself is a short as two or three minutes.

Host: So, can people go to work before or go to work after, do their normal activities, kind of stop off on their lunch hour so to speak or does it really put them out of commission during that time?

Dr. Nagar: Generally speaking, it’s completely outpatient therapy. Again, this will be dependent upon the tumor we are trying to treat. But many patients come in at 7:30 in the morning and then they are at work by 8:30 or come in at the end of the day or take a lunch break and come in for their treatment which is why the dose is delivered over small courses over the entire time versus one large dose at one time, which is done for other tumor types.

Host: So, we’ve talked mostly so far about external beam radiation where a beam is coming from a machine outside aimed toward the inside in a very precise way. The other major area that I’ve at least heard about and may have gotten a little familiar with is a concept of implanted radiation and also, I guess termed seeds. Tell us a little bit about how that differs, why that’s better in some ways, applied to some situations and kind of what that’s all about.

Dr. Nagar: Right so, the seed or the internal radiation is leveraging physics behind radiation therapy. So, seed therapy or what’s called low dose seed therapy or high dose seed, or catheter therapy allows us to deliver a very, very high dose to the tumor itself by implanting the seed into the tumor or the cavity itself and really sparing the normal tissue around it. a lot of cancer subtypes are very amenable to this type of treatment. Prostate cancer is one, cervical cancer is another one where it’s been shown to be more effective in certain cases versus others.

Host: So, the concept is that it’s a higher dose and it’s more precisely given?

Dr. Nagar: Right. I wouldn’t say necessarily it’s more precisely given, but it’s a very high dose and the dose shaping can be for certain tumors can be potentially more advantageous than the external beam form.

Host: So, where are the seeds implanted radiation most commonly used, recognizing that there is some overlap.

Dr. Nagar: Well prostate cancer is a very common use where the seeds are actually placed into the prostate itself and remain there for the rest of that patient’s life. But the radioactivity decreases over time, so the patient is not radioactive for the entire course of their life.

Host: So, that’s done in an operating room, is the patient asleep, kind of like a surgical procedure?

Dr. Nagar: Yes, the patient is sedated during the procedure. Some can undergo the procedure with lighter sedation, just depending upon the complexity of the procedure and where we need to implant the seeds.

Host: And so, I guess the disadvantage is you have a surgical procedure like, but the advantage is it’s one day and you are done more or less as opposed to coming back for several weeks or whatever the normal course is?

Dr. Nagar: Exactly. The course can be one day or a couple of days depending upon the delivery versus let’s say three or four weeks of daily treatment.

Host: Right. So, one question people always ask, am I radioactive if I get radiation? Right, so the patient’s question of can I be around other people I guess to the seeds, maybe a little bit but for regular external beam not a concern.

Dr. Nagar: They are not radioactive at all once the machine is off. There is no radiation in the area. So, they are completely fine to be around infants, and the normal local public around them.

Host: Good. So, every cancer treatment that I have ever seen and heard of has some side effects, surgery, chemotherapy, other drugs, radiation clearly has some side effects. It’s hard to generalize I’m sure because of the place but maybe you can give a couple of examples of common places where radiation is used. What are the typical side effects that patients can expect? And then in a minute we will get to kind of the longer term things that people need to at least be aware of.

Dr. Nagar: Right, so it’s very – as you alluded to, very cancer site dependent because as we’ve gone through this conversation, the radiation is very delivered to one particular area. So, we don’t expect large full body effects unless we are giving full body radiation. And it’s limited to the tumor site around that. So, if we are radiating the skin, there could be a skin reaction. If we are radiating near the bladder, there could be increased urinary frequency. If we’re radiating somewhere near the abdomen, there could be some nausea that develops.

But it’s very site dependent, what part of the body we are radiating because it’s the local organs that are being affected.

Host: So, how are patients monitored for these sorts of side effects? They are being seen regularly obviously and you have treatments to prevent those or to manage those sorts of things?

Dr. Nagar: Exactly. So, certain patients we know will come in with certain predisposing factors that’s going to lead them to have more acute side effects so we will prophylactically medicate them. So, a patient that naturally is nauseous all the time and they are coming in for a seminoma treatment where part of the abdomen has to be irradiated, we will prophylaxis anti-nausea medication. If a patient with urinary symptoms coming in for prostate radiation, we will prophylactically start urinary medications to help with their urine flow. We see them weekly during treatment and we are there everyday if they develop a side effect and then manage that side effect as they are undergoing radiation treatment.

Host: So, one of the other aspects of almost all cancer therapies to some degree or another are the longer term side effects and radiation is no exception. I know that that’s changes a great deal. But what are the things that are at least low risk or some risk long term for patients who have had radiation that at least they and their doctors need to know about to keep an eye out for?

Dr. Nagar: Right. This is a very important question and something a patient should always discuss with their radiation oncologist. Because while radiation can be tolerated and have very few long term complications; when they do develop you want to be aware that they possibly can. And again, it depends on what site is being irradiated.

Host: So, are there any groups of patients where radiation – I should say groups of patients with certain medical issues where radiation is a big concern? So people I had heard at some point, people with autoimmune diseases in certain scenarios, is it a problem in children? What sorts of people really have to have a very special conversation about radiation in a general sense obviously, some of it is site specific.

Dr. Nagar: Right. Exactly. Some are site specific but those that do have certain autoimmune diseases, it depends if they are on active therapy, if that autoimmune disease in the past history when they had it in their early teens or 20s and now is well-controlled. So, those are certain areas where radiation oncologist and the patient need to have that conversation as to what the potential risk is. Like any therapy, surgery, medicine, radiation; it’s balancing the risk to benefits of that therapy versus the side effect profile that might come from it. So, autoimmune diseases is an excellent example where we are trying to speak to the patient as to what the potential risks are and then decide upon what the appropriate dose might be for that particular patient.

Host: So, from a patient perspective, like most things in medicine, where you get your treatment may matter in some situations. And I presume there are patients that are being offered or considered for radiation that are deciding to I go here or there. What are some of the sorts of things that you would advise a patient as they are deciding where I should get my radiation treatment? What should they think about or ask about or look into? And I know there’s been a tremendous investment, I mean you’ve been recruited here among other colleagues. We are really at Weill Cornell doing a lot to expand and grow the capabilities of our program here what are some of the sorts of things that we have. So, what questions should patients ask and then what are some of the things that we in a center like this may offer that maybe isn’t available elsewhere?

Dr. Nagar: Right. So, the one thing every patient should know is to have that patient physician relationship and trusting that physician because that’s the utmost importance to any patient’s care is when you are seeing that physician do you trust what they are saying and are they providing levels of evidence that give you confidence that the physician is well aware of what they are doing.

From a technology standpoint, you want to understand how long they have been doing this, what their expertise is in this particular area treating this particular cancer. Like we’ve alluded to multiple times, it’s very site dependent. It’s very important that the physician has experience treating that particular cancer site over the course of many years. And then of course, the technology. So, what type of machines do they have? What type of technology do they offer? There’s a lot of push into improving the technology so certain things that we have available here are MRI guided imaging therapy which allows us really to focus on the diagnostic quality of MRI and to treat the tumor and avoid normal tissue to treat the tumor in a very small target area as things move around, we are able to treat the tumor, stop the treatment if the tumor moves out of bounds and then bring the tumor back into treatment and treat again.

So, it’s very important for the patient to have confidence not only in that physician but the technology and experience that that physician is offering.

Host: And it sounds like having a team perhaps as much or more so than other specialties where not only the physicists and the radiation oncologists but also others that might be weighing in on the patient’s case, imaging, staff et cetera, is a very important thing given all the moving parts here and the technology involved.

Dr. Nagar: Exactly. So, what we pride ourselves on is having a multidisciplinary team of surgical oncologists, hematologists, medical oncologists, and radiation oncologists deciding on the type of care for that patient and then when the patient comes for radiation, it’s a nursing team, a dosimetrist team, a physicist team and then all the faculty in the room looking over that patient’s treatment plan and then prior to that delivery, approving the plan as the faculty saying this is the right plan for this patient at this dose and this treatment plan.

Host: So, you alluded earlier to I think primarily one of the areas of head and neck cancer and others where radiation interacts with in a favorable way or synergizes with whether it’s chemotherapy, there’s also interest in immunotherapy. What are some of the areas that radiation kind of connects to other cancer treatments in a potentially positive way and what are you most excited about as far as exploiting this in the future whether it’s through studies or emerging treatments?

Dr. Nagar: Right, so radiation has a long history of working by itself, but we know we can do better if we combine it with other modalities of treatment particularly chemotherapy and now the rapidly emerging field of immunotherapy which is quite exciting in our time. Immunotherapy has shown to be beneficial for a certain select subpopulation of patients. The question that’s being investigated at this institution particularly is can we leverage the harmony between radiation and immunotherapy to improve the outcome of patients receiving immunotherapy and making that effect stronger and longer for those patients for that drug delivery.

Host: So, what do you think radiation therapy is going to look like five, ten, fifteen years down the line? Where do you see the field moving?

Dr. Nagar: I think we are going to see even more precise delivery. We’re very interested in functional imaging in terms of we know for example, in lymphoma, patients undergo PET scans that shows uptake in certain areas or where the tumor might be active. More and more chemicals like that are being discovered at this point where we can actually understand the function of that tumor and actually just treat what’s active and leave everything that’s inactive or has already died, leave that tissue away from the radiation.

Also diagnostic imaging is becoming much more sophisticated in that sense. So, we can see definitely what could probably avoid radiation treatment and what really needs it so we can treat a particular area and literally spare everything else.

Host: Well it sounds like a lot happening and I know that there are many patients, some in my family themselves who have benefited from radiation treatment and so, it’s been a great discussion I think to give people an overview of where the field is we will definitely have some more discussions in the future with some of your colleagues as well about kind of where radiation fits in more specific situations. But I think this has been a great overview. So, thank you for taking the time.

Dr. Nagar: Of course. Thank you for having me.

Host: Great. So, I want to encourage our audience to download, subscribe, rate and review CancerCast on Apple podcasts, Google Play Music or online at www.weillcornell.org. We also encourage you to write to us at cancercast@med.cornell.edu with questions, comments and topics you’d like to see us cover more in depth in the future.

That’s it for CancerCast: Conversations About New Developments in Medicine, Cancer Care and Research. I’m Dr. John Leonard. Thanks for tuning in.