M. D. Anderson Cancer Center
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Lisa Garvin: Welcome to Cancer Newsline, [Background music] a podcast series from the University of Texas, MD Anderson Cancer Center. Cancer Newsline helps you stay current with the news on cancer research, diagnosis, treatment and prevention, providing latest information on reducing your family's cancer risk. I'm your host Lisa Garvin. Today, we're talking with Dr. Joe Chang who is an Associate Professor of Radiation Oncology here at MD Anderson and also Director of the Stereotactic Radiation Program. Our subject today is Stereotactic Body Radiation also known as SBRT. Let's start with the elementary, Dr. Chang, what is SBRT?
Dr. Joe Chang: The unique part of SBRT is to deliver very high--large radiation dose to the tumor in and in mean time, minimize the dose exposure to the surrounding critical structure. Compared with Commission on Radiation Therapy which require seven weeks radiation therapy and about seven degree of dose of biologic dose, stereotactic radiation therapy deliver double the dose within one week.
Lisa Garvin: Now, this is not really a new procedure but there have been a lot of developments recently has there not?
Dr. Joe Chang: Right, because recently--because we have a--what we call imaging guided radiations therapy and there was a four dimension in your CT imaging guided treatment planning, we take the motion into consideration. We can deliver dose more precisely to the target it to a--for example, a lung cancer more precisely and in that we can afford to have a tight margin because of verification by CT and more.
Lisa Garvin: Now, people who are may be not familiar who have not undergone radiation therapy, it's very important that they stay still and that they're always in the same position. So, when you're talking about movement, we're talking about movement of organs and the tumors itself, correct?
Dr. Joe Chang: Right.
Lisa Garvin: So in typical radiation therapy, there is a--like a frame that's built to hold them in the same position. But the CT-on-Rails as you described negates the need for such a frame.
Dr. Joe Chang: Right, because for--it's a cone-beam CT or CT-on-Rail, we do it before each procedure. So every single day, we verify, we're talking exactly right spot. We only allow less than two to three millimeter uncertainty with CT-on-Rail or cone-beam CT.
Lisa Garvin: Now, what sorts of cancers are you starting to treat with SBRT?
Dr. Joe Chang: Most of the time, it's that lung cancer, early stage of lung cancer who is not a good candidate for surgical resection because of all medical problems such as diabetes, cardiovascular disease or poor lung function. Another group patient is a patient who have a history of lung cancer has been treated surgically or with definitive radiation therapy, but reoccur in other part of the lung and that group of people either recur from prior cancer or secondary lung cancer, they can be treated with stereotactic radiation therapy. The second group is patient who have a given type of cancer, but the cancer spread from primary, either colon, rectal or pancreatic cancer, sarcoma or melanoma. They spread through the lung or liver or adrenal, we can treat with a stereotactic radiations therapy or SBRT using this technique.
Lisa Garvin: So basically, cancer is that are in the thoracic region, it sounds like.
Dr. Joe Chang: Thoracic or liver or even adrenal.
Lisa Garvin: Now, is this something that's available at all cancer centers or is this something that's only at may be some of the bigger centers like MD Anderson? Is this a standard treatment?
Dr. Joe Chang: Currently for early stage of lung cancer who is not a good candidate for surgical resection, that has been a standard. However, in MD Anderson Cancer Center, we'll have most experienced, we treat about 1,000 patients with this technique. We gained so much experience and we published several paper that's treat the challenging cases for lung cancer. So--and also we have a proton available here if patient need a proton treatment, also use a proton stereotactic proton treatment also available in our institution. So, we do have more--a lot of experienced and also we have all the [inaudible] technology.
Lisa Garvin: So--and I think that that's a distinction that people can't always make about radiation therapy. There are several different types and so stereotactic--the stereotactic part is the intraoperative imaging or you're imaging the tumor site as you are doing the radiation therapy.
Dr. Joe Chang: Right.
Lisa Garvin: So you can actually use other types of radiation therapy in the stereotactic setting.
Dr. Joe Chang: Exactly.
Lisa Garvin: Okay.
Dr. Joe Chang: You can use a proton, IMRT. [Inaudible] four more different type technology but use the concept of stereotactic which is being delivered ablative dose to the target and avoiding surrounding critical structure.
Lisa Garvin: And I know in the radiation therapy world, there's been a lot of work in trying to reduce the number of treatment sessions by introducing a higher dose. Is that kind of where we're moving?
Dr. Joe Chang: Right, exactly. It may--you can imagine for Commission on Radiation Therapy, typically for lung cancer, you need seven weeks of radiations therapy that daily treatment for 35 fraction. Nowadays, for early stage of lung cancer using the SBRT, we finish in four days. Four days compare with seven weeks, 35 fraction. But by a larger dose, doubled almost.
Lisa Garvin: And I know there are obviously concerns about higher doses and what have you seen as far as the effectiveness of fewer treatments and higher doses? Have you--do you have data to kind of bear out that it's a good thing?
Dr. Joe Chang: Sure, you know, our center and also other center published several data, in all hence, the local control which mean the tumor recur in the spot we treated is 98 percent, which means on the two percent of patient recur locally in area which where the data is comparable with surgical resection. That's the unique part about it because we deliver ablative dose to this target, so no [inaudible] what kind of histology by that of dose, it can eliminate the case totally.
Lisa Garvin: In what sort of research are you doing on SBRT? Are you hoping to focus another tumor sites or other types of cancers? What sort of things are you looking at for in the future?
Dr. Joe Chang: Recent project is going on, you know, our center including treat patient with operable early stage of lung cancer. As we all know standard treatment for operable stage one lung cancer is a surgical resection that will either remove one lobe of both lung to [inaudible] dissection. So now the question is whether stereotactic it can be comparable for surgical resection in operable patient. So we're doing phase one--oh no, phase two and also phase three randomized study which mean give 50-50 percent a chance to each group and then randomize the patient to either surgical resection or SBRT. So we'll see whether they are comparable or not. That's the one of major research direction. The second is we're doing patient for challenger case such as a case tumor who are close to the critical structure, or patient has been treated with prior radiation therapy which mean there tolerating radiation poorly, or patient who have other type of cancer and spread to lung, liver or adrenal with multiple mass. So all those case previously is only treated with a palliative chemotherapy, but now we aim for potential cure. That's our research project we are doing and thus, the result look like promising.
Lisa Garvin: And is SBRT used as a front line treatment in these cases or is it adjuvant therapy with surgery and/or chemo? It sounds like it's a front line treatment in many cases.
Dr. Joe Chang: Well it depends. If it's a medically in operable early stage of lung cancer then SBRT is front line treatment for sure. For patients with recurrent or metastatic cases spread to the lung then systematic treatment including chemotherapy, biological treatment will be mainstream treatment but radiation therapy using stereotactic function as the boost to the local area. So it would--can combine with other type of treatment together in many disease situation.
Lisa Garvin: And what are the patients you've used SBRT on, what sort of reaction or feedback have you gotten from them?
Dr. Joe Chang: Well most our patient that I saw up to five years of lung cancer are patient who are treated with stereotactic radiation therapy.
Lisa Garvin: You mean reaching the five-year survival mark.
Dr. Joe Chang: Right, right. Because its definitive treatment will aim for cure for early stage of lung cancer. And the patients love of the procedure first of all is noninvasive. Second, the finishing one week and minimum side effect. Some patients even joke say, "Well, are you sure the machine--you turn on machine because I don't feel anything." So patient love it particularly for people who's more senior, who may not like the idea to open up the chest, so they--we get a very good feedback from our patient.
Lisa Garvin: Let's talk about the typical effects of standard radiation therapy, what are the typical side effects of radiation therapy in general?
Dr. Joe Chang: In general radiation therapy are--is energy so it goes to the skin to hit the target so patient typically have skin reaction. Most of the time, it's just like sun burn, it's tolerable, minimal or occasionally moderate. And second side effect is--as you can imagine, if we're to treat a lung cancer, we're going to burn that part of the lung with radiation, so that part of lung may become scarred down in a row. So if patient have a very poor lung function, additional lung damage, it can cause worsening [inaudible]. But it typically that will happen in about a 10 percent of time. About three percent of time, it could be chronic and severe. Those two are common side effect. Another side effect is chest wall pain. If tumor is close to the chest wall, as you can imagine, it can irritate the chest wall [inaudible] nerve by radiation therapy, so patient may have a pain in the chest wall, that happen about 10 to 15 percent of time. Again, most of like--most of the time, it's mild to moderate. Those three are most common side effect from radiation therapy including stereotactic radiation therapy. Of course, we need to respect that those exposure to esophagus, spinal cord, bronchial plexus and heart, those critical structure, we need to pay attention to. That's the [inaudible] and that if you do the stereotactic radiation therapy, better to go to the main center who have a more experience, who know all the tolerance, dose, and who treat with this technique all the time.
Lisa Garvin: So should patients that are possible eligible should they be asking about SBRT? Is that something they can ask their oncologist about?
Dr. Joe Chang: Sure, if they have early stage of lung cancer, if they have a recurrent lung cancer recur in the lung parenchyma or if have the--have metastatic disease to the lung or liver, adrenal, they should ask to the physician and say, "Well, what's SBRT? Is that another option?" And then get a consult from radiation oncologist, then we can give you assessment to see whether you're a good candidate for SBRT.
Lisa Garvin: Your typical patient for SBRT is early stage lung cancer and. And now, typically, lung cancer is not caught at the early stage, but things are changing on that respect, aren't they?
Dr. Joe Chang: Right, and they--as you all know, the NCI support research project for lung screening program found that with spiral CT screening in high risk patient, screening actively can reduce lung cancer related to death 20 percent--to reduce the 20 percent. So currently, what one unique part of our program is we can integrated to part of a management for a patient who went to a lung screening program and found to have a lung cancer and then they can do in a surgical resection if they can tolerate or they can do SBRT.
Lisa Garvin: So the good--who are considered the high risk groups that would be eligible for lung cancer screening?
Dr. Joe Chang: Typically, a patient who is chronic smokers, smoke more than 30 years or 55-year-old patient who is a high risk for lung cancer.
Lisa Garvin: Great. Thank you very much Dr. Chang.
Dr. Joe Chang: My pleasure, thank you.
Lisa Garvin: If you have questions about anything you've heard today on Cancer Newsline, contact askMDAnderson at 18777-MDA-6789 or online at www.mdanderson.orgs/ask. Thank you for [Background music] listening to this episode of Cancer Newsline. Tune in for the next podcast in our series.
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