With each issue, Trib+Health brings you an interview with experts on issues related to health care. Here is this week's subject:
Dr. Andrew Lee is the medical director of the Texas Center for Proton Therapy in Dallas. He spent 14 years working at the University of Texas MD Anderson Cancer Center, where he helped launch proton therapy treatment – using high energy protons to destroy cancer cells. Lee treated the center's first patient using the technology and also helped to perfect their use of pencil beam scanning, which allows doctors to target the protons to a highly specified area.
Editor's note: This interview has been edited for length and clarity.
Trib+Health: What sort of work did you do at MD Anderson? How did you come to work on proton therapy treatments?
Andrew Lee: Prior to joining Texas Center for Proton Therapy, I was at MD Anderson as a faculty member for almost 14 years... When MD Anderson decided to build a proton center, I helped initiate that clinical program and treated the first patient at MD Anderson on May 4, 2006.
And so a lot of that was just sort of making sure that we have a clinical program in place that was not only safe but also that was going to be effective and patient friendly. Also, we kind of furthered the field. One of the newer developments in proton therapy has been the implementation of something called pencil beam scanning or spot scanning proton therapy, which is a more sophisticated way to deliver protons.
So actually, I treated the first patient in North America with that technology in May of 2008. And, really, fundamentally the goals of proton therapy are very consistent with the overall goals of radiation therapy in general, which is trying to maximize cure rates involving the tumor but minimizing side effect profiles through minimizing exposure to normal tissues.
We have a number of technologies at our disposals to do that, and now proton therapies are included. So a lot of my research at Anderson not only involved just validating the technique as being clinically effective, but also examining how it’s impacting patients involving the quality of life but more specifically using patients' reported quality of life metrics rather than something that would be reported by the physician or the care team. So the quality of life metrics were actually what the patients were saying, not what we were thinking.
Trib+Health: On a technical level, how does the proton therapy technology work to fight cancer?
Lee: So all ionizing radiation, including proton therapy, works in a very similar manner, which is causing damage to DNA, which is the genetic blueprint of cells, including cancer cells. So if that genetic material, that blueprint, is damaged, then a cancer cell can’t divide effectively and a cancer cell that can’t divide is, to use a southern idiom, that dog won’t hunt.
It’s basically not as dangerous anymore and then the cancer cells eventually die out. What proton therapy does is it takes, if you remember high school chemistry, a hydrogen atom is made up of one proton and an electron that spins around it. So what we do is we start out with a tank of hydrogen gas, maybe like a scuba tank, and that will provide enough protons to treat patients for many months.
The electron will be stripped off so then you’re just left with the proton. Now a proton is a subatomic particle, but the key component there is particle. So think about any other particle you had — it could be a BB, it could be a baseball, whatever. If it’s just lying on your desk, a baseball probably is not going to do anything. But if you were to throw the baseball and accelerate it and it hits something, it can do damage.
And that’s what we do. We use a machine called a cyclotron and it takes those protons and it basically spins them in the cyclotron and gets them at their maximum energy, maybe at about two-thirds the speed of light and then those are directed down a beam line using a series of electromagnets to steer and focus the beam to a large machine called a gantry, [which can be point the proton beam] at a patient's tumor. And usually multiple different angles are used to treat the tumor comprehensively.
The nice thing about protons, unlike conventional X-rays, is that they can actually deposit their radiation over a specific area or depth. If you’ve ever gotten an X-ray of your chest or your leg, the reason you can see an image is because the X-ray goes all the way through and they hit a piece of film and that [results in the subsequent] image. Whereas protons can stop sort of halfway in the body and perhaps more precisely right after a tumor, where an X-ray can’t do that.
The analogy there would be the difference between driving a car with four bald tires on wet pavement and hitting the brakes and you wouldn’t expect the car to stop right away, it’s going to eventually stop but it’s going to take some time. Using protons is more like using a car that can literally stop on a dime, over basically a few millimeters.
Trib+Health: How long has this technology been in development? Is it used frequently now? If not, do you see it becoming more prevalent?
Lee: As far as North America is concerned, I would say an excess of 30 years. Most of the early centers were part of physics research laboratories and sort of retrofitted to treat patients in a very crude fashion while still using protons. But I would say in the last five years we’ve seen more advancements in the technology than we have in perhaps the preceding 10 to 20 years…When I first started treating with protons back at MD Anderson in 2006, I think there were only about five operational centers, clinical centers, and now I think in the next year there’s going to be 16.
Trib+Health: Could you elaborate on this idea of side effect free treatment?
Lee: I wouldn’t say it’s a complete lack of side effects because you are getting some normal tissue exposure and sometimes, by virtue of where the tumor is, that may be in a sensitive part of the body. The most ubiquitous form of radiation that is most commonly employed does involve X-rays. And X-rays, even using very high energy X-rays, when they deposit radiation in the body they’ll typically deposit most of the radiation a few centimeters underneath the skin.
Most tumors are not that shallow so therefore to get enough radiation dose deep into the body, you’re kind of really pushing the radiation dose deeper and deeper. So your tissue is getting more radiation than you really wanted... Now you’ve got more radiation when you get the tumor and you have more unnecessary radiation after the tumor. Depending on how much radiation you’re talking about, that can lead to more side effects.
Trib+Health: How will the Proton Therapy Center in Dallas look once it's completed? When will you start accepting patients?
Lee: We’ll have three full treatment rooms, which include two full gantries. What I mean by a gantry is that they can rotate the angle of the beam in a full circle or 360 degrees around the patient. So if we have to treat at different beam angles we can do that. We also will have one fixed beam line, so that just comes straight out from the wall in a horizontal fashion but all three rooms have these robotic couches that can position the patient in a number of different treatments.
I guess the closest analogy is when you take a shower and it’s not a handheld shower, the water is just coming out of the wall. If you want to wash your hair, you move your head into the stream of the water and if you want to wash the rest of your body you position your body appropriately. That’s how the fixed beam line works. Whereas the gantry is more like that nozzle can move in any angle, so you could just stand there and the water would go all around you.
What’s important is that all three treatment rooms have the capabilities to deliver the pencil beam treatments I’ve described. And two of them will also have something called Cone Beam CT, which is the ability to take kind of a cursory, three-dimensional picture of the patient prior to treatment.
So it’s kind of like getting a very rudimentary CAT scan before the patient is treated. We may use that in certain indications. In terms of our first treatment, right now we’re hoping to do it by the end of this calendar year and I think we’re on target for perhaps some time in November. That could change because the system is really complicated But we’re currently doing not only the acceptance testing, but also the physics group is doing a lot of clinical commissioning to make sure everything is ready for patients.
So initially we’ll only have one room up, so at three-month intervals we’ll bring another room up. So it will take us maybe six to nine months to have all three rooms up and running and then to be fully operational, that could take a year or less. But it’s going to take some time. Once we’re at full capacity, I think we can accommodate over 100 patients a day.
Trib+Health: And do you think you’ll actually see those sorts of numbers once you open?
Lee: I think there is an opportunity to do that. One thing I think you have to keep in mind is that the DFW Metroplex is one of the largest metropolitan areas without a proton center. So to have this technology available, not only are we talking about six-and-a-half million people, we’re also talking about people that may be coming from outside of the two hour driving radius that want to have access to this technology and that could be within the state of Texas or out of the state of Texas.
Trib+Health: Do you have any projections for treatment costs? How will it compare to the cost of other treatment methods?
Lee: You can’t have a dollar amount because, for private insurance companies, they negotiate in contracts specific rates with every center independently, and that’s not on the proton or X-ray side, that’s for all medical services. That information is meant to be confidential between the payer and the provider. The one exception might be Medicare rates because it’s a national or federal program.
On a per fraction basis, if you were to deliver the same number of fractions, I think proton therapy might be like 30 percent more, but in terms of absolute dollar amounts, it’s not a huge difference. One of the things that also happens is, we have to think about not only the cost of the treatment, but also the downstream costs associated with what’s happening to the patient. And that can include, if the treatment didn’t go well, there is an increased risk of cancer recurrence which obviously is expensive to deal with and in some cases fatal, but there is also the cost associated with dealing with the side effects of the treatment.
You can think about the costs associated with just doing the medical management, but we also have to be cognizant [about the cost of what’s happening to the patient after treatment]. Let's say the patient is not feeling well, after their traditional radiation, [then they may miss] a day of work. That’s a cost to their employer, or let's say the patient feels sick and not only do they have to stay home, they need a family member to stay with them, so now you have two people out of work.
So there is a cost, I think, associated that goes beyond the medical price. And there are other nuances. Let's say you’ve been treated for cancer and you feel good enough to go to work but when you get to work, and we’ve all been there, you’re just not performing well. You’re like at 70 percent and maybe you’re just limping along. One of the things that we want to do is minimize the impact. We want to minimize the long-term impact of the patient, not only on the cancer but minimize the impact of the treatment.
We all need to be fiscally conscious going forward, that’s true on the payer side and on the provider side, but I think the most important thing is that you have to look at the value of beyond what it costs in terms of dollars and cents. Incrementally, an example might be there are a lot of cars that can go 60 miles per hour, safely. But if you want a car that can do 100 miles an hour safely, there is an incremental cost that’s required to do that.
Correction: Two technical terms used in this conversation – cyclotron and cone beam – were misspelled in an earlier version of this story.