With conventional therapy, radiation is delivered in relatively small doses over the course of several weeks, with patients receiving daily treatments during that time. With Stereotactic Body Radiation Therapy (SBRT), physicians are able to deliver a greater combined dose of radiation over the course of fewer treatments. SBRT has shown dramatically better outcomes than conventional radiation therapy.
Radiation therapy plays a pivotal role in the treatment of lung cancer of all stages and can result in long-term curative outcomes for patients with early stage disease.
Listen in as Sagus Sampath, MD discusses the advantages of Stereotactic Body Radiation Therapy to treat cancer.
Selected Podcast
Stereotactic Body Radiation Therapy: The Latest Technique
Featured Speaker:
Dr. Sampath received his board certification in radiation oncology in 2011. While just beginning his academic career, he has already been first author on six peer-reviewed publications, has been invited to deliver five oral presentations at national meetings.
Learn more about Sagus Sampath, M.D
Sagus Sampath, MD
Sagus Sampath, M.D., is an assistant professor in the Department of Radiation Oncology.Dr. Sampath received his board certification in radiation oncology in 2011. While just beginning his academic career, he has already been first author on six peer-reviewed publications, has been invited to deliver five oral presentations at national meetings.
Learn more about Sagus Sampath, M.D
Transcription:
Stereotactic Body Radiation Therapy: The Latest Technique
Melanie Cole (Host): Radiation therapy plays a pivotal role in the treatment of cancer of all stages and can result in long-term curative outcome for patients with early stage disease. My guest today is Dr. Sagus Sampath. He’s a radiation oncologist at City of Hope, Duarte. Welcome to the show, Dr. Sampath. What is stereotactic body radiation therapy or SBRT?
Dr. Sagus Sampath (Guest): So, SBRT is a fancy acronym that’s been used for almost 10 years now and, really, what it tried to encapsulate is the idea of ablation. Basically, killing the cancer cells at the time of delivery so that the cells do not have the capacity to repair themselves. That’s a major contradistinction to previous podcasts that we’ve had covered on our program with radiation, where radiation therapy can be given to disrupt or damage DNA in the cancer cell but the cancer cell still has a chance to repair. But, with SBRT, it’s a lot different. The dosing is generally four to five times more than traditional radiation per session. And, the total number of treatments as opposed to traditional treatment usually lasting six to eight weeks, SBRT treatments usually lasts about a week to week and a half. So, it’s a much shorter, more potent form of therapy to completely eradicate the cancer where it’s given.
Melanie: So, that’s how it differs from conventional therapy. Can it be used with resection surgery? Is it something that’s done in conjunction with other treatments or is it standalone?
Dr. Sampath: It was developed to be a standalone treatment. The mentality is very surgical in the sense that, just like with surgery, intuitively, we think of the cancer being gone after the procedure. So, similarly this type of radiation is delivered with that same intent and that same mentality. Typically, we are treating intact visible tumors in the body. It is being used in patients who have already had surgery. Sometimes, it’s being done in patients who are about to have surgery, so the idea is maybe treating a rim of margin around the cancer to address any microscopic cancer, and then, maybe have the surgeon take out the visible or gross tumor. So, it’s being used in all combinations but its main role is being used as a definitive treatment.
Melanie: Is this an external beam type treatment or are there some internal parts to it? How does it work?
Dr. Sampath: So, basically, it’s using the same linear accelerator that we have that’s common at all of the radiation oncology clinics that are out there. It’s just the amount of radiation coming from the machine. So, it’s all external beam radiation but the quantity and the way the beam is shaped as it enters the patient is quite different. So, it has elements of IMRT--I know we’ve talked about those terms on previous shows. It uses a combination or IMRT modulation, dose shaping, field shaping, but it uses it on a more--it’s basically IMRT on steroids. It basically uses more levels of shaping along with much higher quantities of radiation dose. And so, you put those two combinations together and you focus it in on a tumor, let’s just say, in the lungs, and you can ablate a cancer then and there. So, that’s really how it works.
Melanie: How do you do these planning scans? How do you know where the tumor is located?
Dr. Sampath: So, similarly to other radiation therapies, traditional external beam radiation, we need to get a CT scan of the patient in order to map out where the therapy needs to go. So, for example, in the lung, we get a patient to breathe normally—and, in the lung, what’s unique about the lung is that it moves normally as the patient breathes in and out, but the lung tumor that’s surrounded by normal lung also moves along with it. And so, our task is to take into account that motion and those changes while the patient is actually breathing, and take that into account at the time of treatment because other areas in the body tend to be more stationary, like the bone or things that are lower down in the pelvis. So, we actually get what’s called a four-dimensional CT scan or a 4D CT scan, and that basically takes multiple quick images of the patient’s breathing and puts that altogether into a movie, basically-- a CT movie. And so, we’re able to actually visualize the cancer moving in the lung. We take all of that data information to say, “Okay, well, we know where the cancer is for most of the time, but we also know where it seems to move some parts of the time and we need to take all of that into account.” And so, it’s a very detailed, step-by-step, slice-by-slice type precision planning that’s required in order to make sure that we eradicate the tumor, especially at the edges--at the boundaries--because we know that’s where cancers can fail.
Melanie: Because this is a moving, constantly moving, organ, that’s absolutely fascinating, Dr. Sampath. What is the difference for a patient if these are higher doses, shorter term? Does the patient feel anything different than conventional therapy?
Dr. Sampath: So, what’s made SBRT such an amazing treatment that’s emerged over the past 10 years, and the reason why it’s been so rapidly adopted, is because of its favorable side effect profile. So, patients are being treated, from their perspective, in a very similar way to what traditional radiation is. From their perspective, they’re lying down on the treatment table and the machine is delivering the same type of radiation that was given 10 years ago but the difference is really invisible. The amount going through is much higher but, remarkably, the patients, as they’re getting the treatment, don’t experience any different side effects as far as while they're getting it. Usually, when I counsel patients, I tell them that because the treatment is so short, we really don’t anticipate any side effects. They may be somewhat fatigued toward the end of treatment or maybe even a month later. But, actually, as opposed to traditional seven or eight week type of radiation where patients sometimes get acute side effects toward the end of treatment, patients that are getting SBRT actually don’t develop, really, any side effects during treatment. And so, the follow-up after treatment is where we usually need to pay close attention and make sure that any side effects that can happen after, get managed properly.
Melanie: Is there any redness or burning?
Dr. Sampath: Typically not. Basically, for something like the lung, the tumors are very deep, and so the inherent physical properties of our radiation beam allow us to spare the skin. And so, the idea is that there’s very, very tiny small beams called “beamlets” that actually can all be given in different directions, and what they do is they all converge at the side of the tumor and so there’s very minimal skin dose because of all the multiple entry points that we use. And so, typically, skin is usually not a problem.
Melanie: Dr. Sampath, where do you see this going, what other types of cancers might this be used for?
Dr. Sampath: The initial site where SBRT was used, where it got its initial inspiration was actually in the brain. So, stereotactic radio surgery, or SRS, is another type of radiation treatment similar to SBRT in the way that it’s given but it was delivered in the brain for many years. And so, it was then taken from the brain and then moved to the rest of the body. That’s why the term SBRT was even coined. They put in the term “body”. But, yes, it’s being used for other areas such as the spine. So, very delicately situated bone tumors in the spine that are close to, say, the spinal column and spinal cord--that’s another area. Pancreas cancer, prostate cancer. So, these are some emerging areas that we’re finding out that perhaps giving more potent treatments over shorter periods of time could be more effective than treating patients for longer periods of time.
Melanie: And, in just the last few minutes--and what great information, Dr. Sampath--give us your best advice for people that are considering SBRT, and, really, what you want them to know about coming to you for a second opinion or, really, what you like to tell them every day about this type of therapy.
Dr. Sampath: Well, I like to tell them that overall the side effects from SBRT are, in general, very low meaning that now we have developed a very long track record from other institutions, our own institution, and really understanding what the normal organs can tolerate. And so, what I tell patients is that, there is a risk for some possible late side effects that can happen after radiation. So, for example, in the lung, there’s a risk that we can cause some inflammation in the normal lung that surrounds the tumor, and that’s called “pneumonitis”. In some lung tumors that are very close to the ribs, sometimes SBRT can cause the ribs to be a little bit weaker, and result in a rib fracture in less than 2% or 3% of cases. Sometimes the nerves that run along the chest wall can be inflamed from SBRT and the patients can develop a chest wall discomfort. What I tell patients is, you have to think about this from a surgical perspective. I've repeated that multiple times to really drive the point home that, for example, with lung cancer, if the surgeon needs to get in to take out that tumor, they have to cut through the rib; they have to cut through the skin; they have to get to that tumor somehow and take it out. And so, there are normal tissues along the way that need to be disturbed in order to actually get the cancer out. And so, I really try to portray a visualization for the patient to say, “Okay, just like a surgeon needs to get in there and get it out, we’re doing a very analogous thing with this SBRT treatment.” And so, when I put it that way, patients seem to really grab on to that message. They also usually are seeing a surgeon as well to figure out what treatment option to choose, and so, I think that really also helps them figure out the pros and cons to both the surgery approach or radiation approach.
Melanie: Tell us about your team at City of Hope.
Dr. Sampath: We have a very talented and multi-disciplinary team as far as radiation and our lung cancer program here. We have very talented surgeons. We have a large group of medical oncologists. The way it works as far as patients getting SBRT is that they go through a multi-disciplinary consultation with our surgeons, our radiation doctors--usually myself—and then a medical oncologist. And, even in the early stage patients that may not need chemotherapy, we make sure that most patients see everybody. That way, they know all the roles that the various therapies play. As far as radiation, our radiation oncology department has very talented therapists that are very technically skilled at setting up the patients because it’s very important that these patients are in the exact same position every day for their radiation because we only have five treatments. So, for example, over a week, we give five treatments. Every treatment counts. And so, we have to make sure that every day these patients are setup properly We have very dedicated and talented therapists to make sure that whatever the doctor is trying to model and plan actually gets delivered.
Melanie: Thank you so much for being with us today, Dr. Sampath. It really is absolutely fascinating. You're listening to City of Hope Radio. For more information, you can go to CityofHope.org. That's CityofHope.org. This is Melanie Cole. Thanks so much for listening.
Stereotactic Body Radiation Therapy: The Latest Technique
Melanie Cole (Host): Radiation therapy plays a pivotal role in the treatment of cancer of all stages and can result in long-term curative outcome for patients with early stage disease. My guest today is Dr. Sagus Sampath. He’s a radiation oncologist at City of Hope, Duarte. Welcome to the show, Dr. Sampath. What is stereotactic body radiation therapy or SBRT?
Dr. Sagus Sampath (Guest): So, SBRT is a fancy acronym that’s been used for almost 10 years now and, really, what it tried to encapsulate is the idea of ablation. Basically, killing the cancer cells at the time of delivery so that the cells do not have the capacity to repair themselves. That’s a major contradistinction to previous podcasts that we’ve had covered on our program with radiation, where radiation therapy can be given to disrupt or damage DNA in the cancer cell but the cancer cell still has a chance to repair. But, with SBRT, it’s a lot different. The dosing is generally four to five times more than traditional radiation per session. And, the total number of treatments as opposed to traditional treatment usually lasting six to eight weeks, SBRT treatments usually lasts about a week to week and a half. So, it’s a much shorter, more potent form of therapy to completely eradicate the cancer where it’s given.
Melanie: So, that’s how it differs from conventional therapy. Can it be used with resection surgery? Is it something that’s done in conjunction with other treatments or is it standalone?
Dr. Sampath: It was developed to be a standalone treatment. The mentality is very surgical in the sense that, just like with surgery, intuitively, we think of the cancer being gone after the procedure. So, similarly this type of radiation is delivered with that same intent and that same mentality. Typically, we are treating intact visible tumors in the body. It is being used in patients who have already had surgery. Sometimes, it’s being done in patients who are about to have surgery, so the idea is maybe treating a rim of margin around the cancer to address any microscopic cancer, and then, maybe have the surgeon take out the visible or gross tumor. So, it’s being used in all combinations but its main role is being used as a definitive treatment.
Melanie: Is this an external beam type treatment or are there some internal parts to it? How does it work?
Dr. Sampath: So, basically, it’s using the same linear accelerator that we have that’s common at all of the radiation oncology clinics that are out there. It’s just the amount of radiation coming from the machine. So, it’s all external beam radiation but the quantity and the way the beam is shaped as it enters the patient is quite different. So, it has elements of IMRT--I know we’ve talked about those terms on previous shows. It uses a combination or IMRT modulation, dose shaping, field shaping, but it uses it on a more--it’s basically IMRT on steroids. It basically uses more levels of shaping along with much higher quantities of radiation dose. And so, you put those two combinations together and you focus it in on a tumor, let’s just say, in the lungs, and you can ablate a cancer then and there. So, that’s really how it works.
Melanie: How do you do these planning scans? How do you know where the tumor is located?
Dr. Sampath: So, similarly to other radiation therapies, traditional external beam radiation, we need to get a CT scan of the patient in order to map out where the therapy needs to go. So, for example, in the lung, we get a patient to breathe normally—and, in the lung, what’s unique about the lung is that it moves normally as the patient breathes in and out, but the lung tumor that’s surrounded by normal lung also moves along with it. And so, our task is to take into account that motion and those changes while the patient is actually breathing, and take that into account at the time of treatment because other areas in the body tend to be more stationary, like the bone or things that are lower down in the pelvis. So, we actually get what’s called a four-dimensional CT scan or a 4D CT scan, and that basically takes multiple quick images of the patient’s breathing and puts that altogether into a movie, basically-- a CT movie. And so, we’re able to actually visualize the cancer moving in the lung. We take all of that data information to say, “Okay, well, we know where the cancer is for most of the time, but we also know where it seems to move some parts of the time and we need to take all of that into account.” And so, it’s a very detailed, step-by-step, slice-by-slice type precision planning that’s required in order to make sure that we eradicate the tumor, especially at the edges--at the boundaries--because we know that’s where cancers can fail.
Melanie: Because this is a moving, constantly moving, organ, that’s absolutely fascinating, Dr. Sampath. What is the difference for a patient if these are higher doses, shorter term? Does the patient feel anything different than conventional therapy?
Dr. Sampath: So, what’s made SBRT such an amazing treatment that’s emerged over the past 10 years, and the reason why it’s been so rapidly adopted, is because of its favorable side effect profile. So, patients are being treated, from their perspective, in a very similar way to what traditional radiation is. From their perspective, they’re lying down on the treatment table and the machine is delivering the same type of radiation that was given 10 years ago but the difference is really invisible. The amount going through is much higher but, remarkably, the patients, as they’re getting the treatment, don’t experience any different side effects as far as while they're getting it. Usually, when I counsel patients, I tell them that because the treatment is so short, we really don’t anticipate any side effects. They may be somewhat fatigued toward the end of treatment or maybe even a month later. But, actually, as opposed to traditional seven or eight week type of radiation where patients sometimes get acute side effects toward the end of treatment, patients that are getting SBRT actually don’t develop, really, any side effects during treatment. And so, the follow-up after treatment is where we usually need to pay close attention and make sure that any side effects that can happen after, get managed properly.
Melanie: Is there any redness or burning?
Dr. Sampath: Typically not. Basically, for something like the lung, the tumors are very deep, and so the inherent physical properties of our radiation beam allow us to spare the skin. And so, the idea is that there’s very, very tiny small beams called “beamlets” that actually can all be given in different directions, and what they do is they all converge at the side of the tumor and so there’s very minimal skin dose because of all the multiple entry points that we use. And so, typically, skin is usually not a problem.
Melanie: Dr. Sampath, where do you see this going, what other types of cancers might this be used for?
Dr. Sampath: The initial site where SBRT was used, where it got its initial inspiration was actually in the brain. So, stereotactic radio surgery, or SRS, is another type of radiation treatment similar to SBRT in the way that it’s given but it was delivered in the brain for many years. And so, it was then taken from the brain and then moved to the rest of the body. That’s why the term SBRT was even coined. They put in the term “body”. But, yes, it’s being used for other areas such as the spine. So, very delicately situated bone tumors in the spine that are close to, say, the spinal column and spinal cord--that’s another area. Pancreas cancer, prostate cancer. So, these are some emerging areas that we’re finding out that perhaps giving more potent treatments over shorter periods of time could be more effective than treating patients for longer periods of time.
Melanie: And, in just the last few minutes--and what great information, Dr. Sampath--give us your best advice for people that are considering SBRT, and, really, what you want them to know about coming to you for a second opinion or, really, what you like to tell them every day about this type of therapy.
Dr. Sampath: Well, I like to tell them that overall the side effects from SBRT are, in general, very low meaning that now we have developed a very long track record from other institutions, our own institution, and really understanding what the normal organs can tolerate. And so, what I tell patients is that, there is a risk for some possible late side effects that can happen after radiation. So, for example, in the lung, there’s a risk that we can cause some inflammation in the normal lung that surrounds the tumor, and that’s called “pneumonitis”. In some lung tumors that are very close to the ribs, sometimes SBRT can cause the ribs to be a little bit weaker, and result in a rib fracture in less than 2% or 3% of cases. Sometimes the nerves that run along the chest wall can be inflamed from SBRT and the patients can develop a chest wall discomfort. What I tell patients is, you have to think about this from a surgical perspective. I've repeated that multiple times to really drive the point home that, for example, with lung cancer, if the surgeon needs to get in to take out that tumor, they have to cut through the rib; they have to cut through the skin; they have to get to that tumor somehow and take it out. And so, there are normal tissues along the way that need to be disturbed in order to actually get the cancer out. And so, I really try to portray a visualization for the patient to say, “Okay, just like a surgeon needs to get in there and get it out, we’re doing a very analogous thing with this SBRT treatment.” And so, when I put it that way, patients seem to really grab on to that message. They also usually are seeing a surgeon as well to figure out what treatment option to choose, and so, I think that really also helps them figure out the pros and cons to both the surgery approach or radiation approach.
Melanie: Tell us about your team at City of Hope.
Dr. Sampath: We have a very talented and multi-disciplinary team as far as radiation and our lung cancer program here. We have very talented surgeons. We have a large group of medical oncologists. The way it works as far as patients getting SBRT is that they go through a multi-disciplinary consultation with our surgeons, our radiation doctors--usually myself—and then a medical oncologist. And, even in the early stage patients that may not need chemotherapy, we make sure that most patients see everybody. That way, they know all the roles that the various therapies play. As far as radiation, our radiation oncology department has very talented therapists that are very technically skilled at setting up the patients because it’s very important that these patients are in the exact same position every day for their radiation because we only have five treatments. So, for example, over a week, we give five treatments. Every treatment counts. And so, we have to make sure that every day these patients are setup properly We have very dedicated and talented therapists to make sure that whatever the doctor is trying to model and plan actually gets delivered.
Melanie: Thank you so much for being with us today, Dr. Sampath. It really is absolutely fascinating. You're listening to City of Hope Radio. For more information, you can go to CityofHope.org. That's CityofHope.org. This is Melanie Cole. Thanks so much for listening.