Radiation Therapy Options

Phillip Koo, MD [00:00:00] Let’s say the patient decided to go with radiation therapy. Dr. Vapiwala, there are so many different types of radiation therapies out there. You see billboards, CyberKnife, I’ve heard EBRT, SBRT IMRT, brachytherapy, proton therapy, a lot to cover there. So, break it down for us and what do patients need to know? 
 
Neha Vapiwala, MD [00:00:21] Absolutely, it is truly an alphabet soup, right? So, I think patients, probably the best way to think of this is two basic categories. EBRT is a general term for external beam radiotherapy. And then brachytherapy, by contrast, is essentially brachy, like the prefix refers to short distance. So, it’s therapy at a short distance because it’s radioactive sources delivered directly to the tumor. So that has a more invasive component, and you can think of that as internal delivery. So, you have the external EBRT, then you have brachytherapy. Now, brachytherapy can be used on its own for a relatively early stage clinically localized prostate cancer, but oftentimes we will use it in combination with external beam radiotherapy for select cases where the thought is, okay, there’s a lot of cancer within the prostate. They’re not proceeding with surgery for whatever reason, and perhaps there is cancer even outside the prostate, so we’re trying to get the advantages of direct delivery of radiotherapy to the prostate and some of the advantages of brachytherapy are that it can deliver the least amount of radiation, and in many cases, no radiation to the nerve bundles, the neurovascular bundles that sit outside the prostate, which can be connected to preservation of erectile function. So, there might be that advantage. And then meanwhile, you use the external component, but you need less of it because you did a brachytherapy component. And the external beam component is now addressing the cancer that might be outside the prostate. So that might a reason why you do the combo. But for patients who are going to get EBRT, just external beam radiotherapy. That’s where a lot of the alphabet soup comes in. So, there’s SBRT which is stereotactic body radiation therapy. It’s a form of radiotherapy that has to do with the way in which the radiation is delivered allows for very precise, what we call conformal delivery of the dose in very high dose per treatment which then requires fewer treatments. So, you don’t have to come in. For five days a week for many weeks, typically it’s three or five treatments over let’s say a couple of weeks. And by giving higher doses, you don’t need as much because it’s felt to be biologically as effective as a course that was drawn out over many weeks with a lower dose each day. Some will argue it’s even more bang for your buck and more dose by having given it in a large punch. But the way that we’re able to do that really has so much to do with modern imaging, modern radiotherapy techniques, the types of, we have, for example, CyberKnife you mentioned, it’s really essentially a linear accelerator, which is a machine that delivers photon-based external beam radiation with six degrees of freedom. So, it’s sort of our version of a cool DaVinci robot, but that really allows you to come in with the dose from many different angles and really limit the exposure to the surrounding tissue. So, a lot of excitement around SBRT for clinically localized prostate cancer. And then the other forms of EBRT are the kind that are more traditional, if you will, more fractionated. So that means lower dose per day over a number of treatments, with the feeling that that also has a long track record of safety and outcomes and within that category, a typical regimen is 20 to 28 visits, five days a week. And within that category, you can have photon-based treatment. So, you can think of that like a wave of energy. And that is typically referred to as IMRT, or intensity modulated radiation therapy, or particles. So, particles as opposed to waves, particles of energy, and a common example of particle therapy in prostate cancer is proton therapy. So, again, I know that’s still a lot to digest, but if you think of it sort of in that, is it external beam or is it brachy, is it internal? And within external beam, is a three or five visits and sort of large treatments per day, in which case it’s SBRT, or is it drawn out over a number of weeks, in which it might be IMRT, or it might be proton therapy, depending on where you are and what your situation is, and there might be potential advantages or disadvantages to either. 
 
Phillip Koo, MD [00:05:06] So then, okay, that’s good to know. So, CyberKnife sort of falls under that SBRT category. 
 
Neha Vapiwala, MD [00:05:09] It’s a way of delivering SBRT. So, it’s not a treatment in and of itself. It’s sort of a, it’s how you think of Kleenex. Kleenex is actually a tissue. So, CyberKnife is a type of SBRT, a way to deliver SBRT, but not the only way to do it. 
 
Phillip Koo, MD [00:05:25] So then the big question is how do patients choose, or can they choose? Oftentimes, patients often don’t think about, they’re just told, show up to this center, get radiation done, but there are clearly gonna be differences between all this. How do patients feel empowered about getting the right treatment? 
 
Neha Vapiwala, MD [00:05:40] Yeah, great question. So, radiation oncologists, you know, who treat prostate cancer patients are very familiar with certain criteria that are pretty well established and published, and then they might have their own nuances from their own personal practice of, say, volume size, so the size of the prostate gland, ideally actually measured via ultrasound as opposed to calculated or estimated from MRI. And there will be criteria where you say, this is not ideal for brachytherapy or brachytherapy alone. This prostate is too big or too small for SBRT. This patient’s urinary symptoms score, when they come in to see me, often measured with the IPSS or international prostate symptoms score. But there are other tools that we can use. They’re way too symptomatic. They have way too many obstructive and urinary urgency frequency type symptoms that I’ve worked with my urology colleague. This is as good as it’s going to get. And maybe that patient is someone where you do go slow and steady and you don’t do a combination external beam or brachy because you’re worried about worsening that over the long term. You might have patients where there is really a goal of getting the treatment done because you’re very worried that for various reasons, whether it’s insurance, social reasons, other health reasons that they are not gonna get treatment unless you make it easy and convenient for them. And maybe it’s not optimal, but it’s the best thing for this patient. Otherwise, you risk them potentially falling off the grid and coming back with advanced disease. And maybe you just say, you know what? Let me get this done in five treatments for you. At least you’ll have had some treatment. So. Sometimes it’s actually really, you know, negotiating, okay, what’s the best that we can do for this patient who’s otherwise scared or otherwise limited in their travel or whatever else. So, so many myriad factors. And then as we started this conversation, you know, the goals of the patient, what are they willing to compromise? Are they very, very concerned about dose to the nerve bundles? Are they are very, very concerned about low dose of radiation to the surrounding tissues, which in theory should not be a problem, but in general, we follow this principle called ALARA, as low as reasonably achievable. And what that means is if I can achieve a safe, effective radiotherapy plan, but do it with minimal dose to the surrounding structures, that’s always preferable. And sometimes in those patients, that’s when something like proton therapy or SBRT being highly conformal or even brachytherapy may be preferred. So, it gets very nuanced very quickly, But I do think. With repeated conversations like this, with multiple conversations with all your physicians, with resources like what PCF offers. Hopefully patients can feel more educated and informed because it can be quite overwhelming. 
 
Phillip Koo, MD [00:08:39] Yeah, you know, even for myself, it feels a little overwhelming. So, the question is, how do you pick a radiation oncologist? Because I imagine part of the selection process is the physician themselves, their background, their training, their experience. But then another piece is what equipment and what technology do they have available? Because I imagined not every center is going to have every single type of radiation treatment available. So, what should patients do? 
 
Neha Vapiwala, MD [00:09:05] Yeah, I mean, for sure there is a technical expertise element very similar to surgery because it’s not a, we’re not prescribing a medication that’s pretty standard that anyone can deliver. It is very technical what we do. So, there needs to be that comfort level with the radiation oncologist. But yeah, you might inquire, what’s the volume of prostate cancer patients that you see and that you treat? And how does your radiation therapist team operate and what’s their level of training? Because remember, they’re the individuals who are actually delivering the radiotherapy on a day-to-day basis, and they are highly skilled professionals in their own right, but that might be something that a patient wants to understand and know about. And yes, what are the technologies that you have available? And are you pushing me towards a particular form of radiotherapy because that happens to be the only one you have here in your center? Or are you giving me a clear view of all the different forms and why you feel that X is better than Y? And I think it’s very fair to try and see someone, I practice in a center that has access to all of the technologies I just said, and I feel very lucky to be in that kind of environment because it allows me to tell all my patients, you can have this, you can have that, and whether you have it here or you’re here for a second opinion and I send you to another doc, that’s not the issue, but at least I feel well-versed in being able to speak to you about all these options and not just the one that I happen to have in my facility. So that’s something that I think, you know, as a patient, you wanna empower yourself with that information and feel free to ask the questions. It’s not dissimilar from what you might ask your surgeon in terms of case volume, case experience, how many robot cases have you done? 
 
Phillip Koo, MD [00:10:50] Great. So, you know, you’re going down the radiation path, what should patients do to prepare before radiation starts in order to maximize their outcomes afterwards? 
 
Neha Vapiwala, MD [00:11:01] Yeah, so certainly if they have existing urinary, lower urinary tract symptoms, a lot of obstruction, a lot of frequency, urgency, we try to work with them and usually they have a urologist that may have existed long before the cancer diagnosis that we work with to try and optimize that in terms of medication or other therapies. We do often, you know, in terms of bowel regimen and getting you into a regular bowel movement regimen, if you’re not already somebody who has regular bowel movements, if you err towards constipation, or if you have frequent loose bowel movements. Trying to really optimize that with the help of our nursing team, our nutritionists that we have, and of course working with the patient and their other doctors. If there are medications that might be known to interfere, generally you can, as a patient, stay on all your typical medications. You don’t have to stop anything. We don’t stop anticoagulants or other things that are needed. But if there are some elective things that you’re doing, you know, you’re taking a baby aspirin, but no one really needed you to, or there’s other herbs and supplements you’re doing, we try to take a good look at that, make sure there isn’t anything that would potentially interfere. And then a lot of it is really encouraging patients to live their regular lives as much as they possibly can, knowing that they have to come in and the best way to get through radiotherapy and to get through all the different, whether it’s five treatments or 28 or what have you, is to try and be as relaxed as possible, to follow the instructions. And I know that’s easier said than done, but I do find the patients that do the best and that are the easiest to reproduce every day on the treatment machine are the ones that, you know, have learned how to feel comfortable, feel in control and let the team kind of do the work that needs to happen. But those are just some of the higher-level things. And certainly. If there is going to be any weight loss that’s expected these days, you have to ask patients, are they on a GLP-1 drug, for example? If there’s gonna be dramatic weight fluctuations, that really is discouraged when you’re on radiotherapy because when we’re doing that customized planning session for each individual patient, it’s very personalized and we’re taking your anatomy, your measurements, not just the prostate, but everything really in the pelvis, in the abdomen and pelvis region. If there’s gonna be dramatic fluctuations for whatever reason, that can really alter all of our measurements and all of what we call dosimetry, all of planning parameters. And so again, if it happens, we can deal with it. There’s something also called adaptive radiation therapy these days, where we can really day-to-day make changes and re-plan the patient, which is an amazing technology as well, that I’ll mention another alphabet soup, adaptive ART often. But in general, we try to make sure patients are in a stable weight zone when we start. So that’s another thing that comes to mind.