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Dr. Mike Smith (Host): Radiosurgery is surgery using radiation. It's the destruction of precisely selected areas of tissue using ionized radiation rather than excision with a blade. Welcome to The GW HealthCast. I'm Dr. Mike Smith, and today's topic, Advances in Radiosurgery. My guest is Dr. Sharad Goyal. Dr. Goyal is Chief of The GW Radiation Oncology Division at The GW Cancer Center and Professor of Radiology at The George Washington School of Medicine and Health Sciences and is affiliated with The George Washington University Hospital. Dr. Goyal, welcome to the show.

Dr. Sharad Goyal (Guest): Thank you for having me.

Host: In my little teaser there, I gave a little definition — you can find that anywhere on Google, a basic definition of Radiosurgery — but let's have the expert, yourself here, help the audience understand just what is radiosurgery.

Dr. Goyal: Okay. Just to give you a little bit of background, the concept of radiosurgery was first described by a Neurosurgeon named Lars Leksell in the 1950s. He proposed radiosurgery as an alternative to open brain surgery. He proposed it to avoid doing brain surgery in patients that may be too sick to get brain surgery. Over time, radiosurgery has emerged as a unique discipline involving surgeons, radiation oncologists, and physicists.

The basic concept of radiosurgery relies on the principle of precisely delivering high doses of radiation therapy to a target, and that target is typically some form of cancer located either in the brain or the body.

Host: Let me ask you something with that. I know my listening audience, the minute they hear high-dose radiation they get a little nervous. What does that really mean? Can you tell us what does that mean to them as a patient? Is the high dose controlled? When you say "precise" what does that really mean? How is that high dose controlled?

Dr. Goyal: Okay, so that's a very good question. When we talk about high doses of radiation, I'd just like to — when I talk about this with a patient I like to give them the alternative. The alternative is having your brain cut into and having the risk of infection, having the risk of having permanent weakness or paralysis from brain surgery. Radiosurgery is an outpatient procedure. This procedure typically takes between 30 and 60 minutes, and patients who drive in can drive home. There is no downtime. They can go back to work immediately, and they typically feel quite well.

Getting to your point about high doses of radiation and what that means for the patient. Basically, patients who are undergoing this treatment do not feel anything during the radiation. They are awake. They are conscious, and what they see or experience is a machine that moves around them delivering them the treatment.

The concept of radiosurgery stems from radiation therapy, and radiation therapy typically is a treatment where we deliver radiation therapy on a daily basis over the course of six, seven, eight, or even nine weeks time. We give a little bit of radiation each day, and the damage that the radiation does on a daily basis to the cancer builds up over time. By the end of the six or nine weeks, the cancer is effectively eliminated.

Host: Right.

Dr. Goyal: Radiosurgery is kind of a shift in that concept where instead of giving low-dose radiation over the course of many weeks, we're giving high-dose radiation over the course of one day or up to five days.

Host: Ah, got you.

Dr. Goyal: A decision of one to five days is based upon the location of the tumor, the type of tumor, et cetera, et cetera.

Host: Does that mean — with those cases where high-dose can be used for one to five days — does that mean — is one of the innovations here the ability to be much more precise in targeting, say, a tumor?

Dr. Goyal: Correct. Again, the concept of radiosurgery has evolved over time. Currently, in 2019, with the types of imaging that we are able to offer patients, we have sub-millimeter accuracy when we deliver the radiation treatment.

Host: Wow.

Dr. Goyal: And those are innovations in imaging and innovations in the delivery of the radiation therapy.

Host: And Dr. Goyal, how has that — in general, how has radiosurgery, in your opinion then, how has it affected or changed cancer treatment or cancer outcomes?

Dr. Goyal: Okay. When we are able to offer patients radiosurgery, we're not trying to detract or take away from a patient that needs surgery. My thought is, and what I tell every single patient, is that nothing can beat a great surgery. But if the surgery is going to leave the patient with permanent paralysis or deficits like oxygen-dependence, then they may not want to have surgery or surgery may not be indicated. Our treatment is an adjunct to surgery.

There are many studies that have been done. These are large studies taking hundreds or thousands of patients and giving half of them open surgery, whether it's in the lungs or prostate, or brain, and then the other half gets radiosurgery. In those studies, the patients getting radiosurgery have the same outcomes as patients getting open surgery. There are many benefits to open surgery, but in patients that either don't want open surgery or can't get open surgery, we have a treatment option available to them.

Host: Well, that's interesting, Dr. Goyal. Do you ever — with those kinds of studies, and I know that probably more needs to be done, more definite conclusions probably need to be drawn, and I get that — but with those kinds of results, when you look at how high-dose radiosurgery, in particular, can be one to five days, you're not cutting into anybody, there's less risk of infection and all that kind of stuff. If the outcomes are just as good as that traditional surgery, do you ever see in the future radiosurgery being the first place to go?

Dr. Goyal: Oh, that's a very difficult question. I may make it seem like radiosurgery is the best thing since sliced bread, but there are side-effects of radiation, and we typically do not offer radiosurgery, or we tend to push patients towards open surgery in a variety of situations. Number one, if they're young. The reason for that is radiation therapy can cause cancer. Even though we're using radiation to kill cancer, 10, 20, 30 years down the road, there may be a 1 or 2 percent risk of that patient developing a second cancer. If that young patient has a long life-expectancy, we will be pushing them to undergo an open surgery.

Host: Got you.

Dr. Goyal: That's one example. Each patient is different. I do feel that radiosurgery does have a place in the battle against cancer. It will never replace surgery.

Host: Got you. Speaking of the future of radiosurgery, where do you see this type of treatment going? What's on the horizon in terms of innovation?

Dr. Goyal: Okay, that's a very good question. There are several things that are here or will be coming down the pike. One is a machine that uses an MRI to help guide radiation therapy. You can use this for standard radiation treatment, or you can use it for radiosurgery. Imagine if you can get a very high-quality MRI image that helps you target the tumor, and then on the day of the treatment we can take another MRI, and we can better assess where that tumor is at that day, whether it's grown, or whether it's moved, or if it's close to another organ, we can change our radiation delivery to either maximize dose to the tumor and minimize radiation to the surrounding organs.

Other advents in radiosurgery include basically modifications on existing systems to help the radiation be more accurate.

Host: And that's really interesting, Dr. Goyal, it seems a lot of this is coming down to really controlling where that radiation is going, right? If we can more and more improve that precision, that seems to be where the power of radiosurgery lies, right? If I can give a higher dose, and it's not hitting any other surrounding organs, that means I have a better chance of killing that cancer, less chance of damage to organs and maybe those future cancers, right? Is that really — it's becoming precise — is that where you think most of the research is heading towards?

Dr. Goyal: Yes, okay. There is another angle to radiosurgery, and that's the concept of targeting a tumor in one part of your body and then seeing a response in other tumors in other parts of your body that were not treated with radiation, okay? That is a concept that has to deal with how radiation modulates the immune response in a patient. Basically, if I target tumor in a patient's lung, that will help stimulate their immune system to ramp up, and their immune system will help target any cancer cells that may be in other parts of the body. Something that many investigators are looking at nationally and internationally is combining radiation therapy with combinations of immunotherapy. Immunotherapy is drugs that also help ramp up your immune system.

Host: Right. That's very, very interesting isn't it, Dr. Goyal? It's that concept, that idea that a little bit of stress is actually good in some ways, right? It's a whole class of study called hormesis, and that's a very interesting maybe future, positive benefit of radiosurgery. You know, Dr. Goyal, this has been a fascinating conversation. Just to kind of summarize for the audience, what would you like them to know about radiosurgery?

Dr. Goyal: Radiosurgery is a cancer treatment where we are able to deliver high doses of radiation in one to five treatments. This treatment is equivalent to open surgery whether it's brain surgery or lung surgery for many different types of cancers. It is a non-invasive, outpatient procedure, typically taking 30 to 60 minutes a day. We offer it to patients in conjunction with surgeons and medical oncologists. We typically make decisions as a multidisciplinary group, and we try to offer patients the most tailored approach to their treatment.

Host: Right. Fantastic summary, Dr. Goyal. I want to thank you for the work that you're doing, and also, thank you for coming on the show today. You're listening to the GW Healthcast. Please visit GWDocs.com to get connected with Dr. Goyal or another provider, or call 1-888-4GW-DOCS to schedule an in-person or virtual appointment.