Historically radiation side effects and cure rates were not comparable to what surgery could achieve. However, with breakthroughs in radiation, computerized beam radiation now rivals surgery for cure rates and minimizes the risk of side effects.
This episode of PROSTATE PROS compares and contrasts the three types of computerized beam radiation: IMRT, IMPT, and SBRT. The episode also covers how to prevent and manage side effects of radiation therapy.
Dr. Scholz: [00:04] Welcome to PROSTATE PROS. I’m Dr. Mark Scholz and this is my cohost Liz Graves.
Liz: [00:08] Historically, radiation side effects were worse and cure rates were lower than with surgery, but that was with the older conformal beam radiation. Now with breakthroughs in radiation, radiation oncologists use what’s called computerized beam radiation, which has far fewer side effects and better cure rates. Dr. Scholz, can you explain how radiation works?
Dr. Scholz: [00:32] Everyone is familiar with radiation from when they get an X-ray. Well maybe you’re not familiar with it because it’s invisible. If you stand in front of the machine and you’re getting a chest X-ray, you may hear a click or something as the machine goes off. The invisible X-rays pass through your body, exit, and hit a film, so they have an image of your ribs and your heart. So with radiation treatment, a much larger dose is administered to a much smaller area. By giving repeated treatments on a daily basis, over a period of time, the radiation basically penetrates into the cancer cells and those cancer cells develop problems with reproduction. The messed up DNA inside the cancer cell causes it to die over time.
Liz: [01:27] So if radiation is just like getting an X-ray, you don’t feel anything during the procedure?
Dr. Scholz: [01:33] That’s correct. If you go to a specialized facility and undergo therapy, they’ll put you in a room that has a thick walls around it and a machine will aim at your body and spin around, but you won’t see anything or feel anything during the treatment. There can be some side effects that occur over time with repeated treatments, but the actual day-to-day treatment is invisible and you can’t feel a thing.
Liz: [01:59] Okay. So a typical treatment of radiation takes about 15 to 30 minutes?
Dr. Scholz: [02:05] For each visit, yes. The doctors that do radiation therapy have one of the best schedules: they only work Monday through Friday, no weekends. When patients are given ongoing therapy they have treatment on a sequential basis. So each visit may last about 15 to 30 minutes.
Liz: [02: 25] In a previous podcast we covered seed radiation. Now we’re talking about beam radiation, which has three types: IMRT, SBRT, and IMPT. Can you give us a quick overview of each type?
Dr. Scholz: [02:41] All of these methodologies require equipment that focuses a beam of radiation on a specific target in the body where the cancer is. The only difference between IMRT (intensity modulated radiation) and SBRT (stereotactic body radiation), is that the treatment is given much more quickly in the men getting SBRT. IMRT people will go in Monday through Friday for a five to nine week period. SBRT treatments require only about five or six visits over a ten day period. You mentioned IMPT, Liz, intensity modulated proton therapy, and it’s a good thing to realize that there are older, less developed types of proton therapy that I would definitely avoid. What makes modern radiation so special compared to the older technology is the precision targeting. In the old days, there was a lot of overspray of radiation into the surrounding organs. This is why people would develop intestinal problems or bladder problems that in some cases would be lifelong. Back in the 1990s, our practice, which has always specialized exclusively in prostate cancer, avoided radiation almost completely, but when the technology changed and intensity modulation started to be accessible—much more accurate targeting is really what intensity modulation is— this changed both radiation therapy, IMRT, and proton therapy, IMPT (intensity modulated proton therapy). So the real difference with proton therapy is that the radiation itself is slightly different in that instead of consisting of photons, it consists of protons. The proton folks love to claim that it has superior properties to photons. Honestly in my experience using both of these rather extensively, I see essentially no difference between IMPT and IMRT.
Liz: [04:56] One thing we hear all the time is that you can’t do surgery after you’ve had radiation. Is that true?
Dr. Scholz: [05:03] Actually, it is possible to do surgery after radiation. However, the side effects of surgery, which are already bad, even when it’s given before radiation, become even worse when it’s given after radiation. This is one of the last few arguments by the surgeons to do surgery. The idea is to hold the radiation in reserve if in case the surgery is ineffective. I think that’s a really terrible argument because if radiation doesn’t work there are a variety of good options: Cryotherapy, for example, HIFU, actually further radiation is feasible. So at one point when there were only two options, and when the radiation was really bad, again, talking about back in the 1990s, that sequencing argument probably had some validity, but it’s way outdated and not applicable these days.
Liz: [05:59] One thing I just quickly want to mention is that radiation is targeting the prostate gland as a whole, not the tumor inside the gland.
Dr. Scholz: [06:10] I think that’s a good distinction. There are sometimes marketing materials that give the false implication that the radiation therapists are targeting just the tumor. Interestingly, focal radiation or focal treatments with HIFU or cryotherapy are feasible, although most are still considered experimental. So whenever we’re talking about IMPT, IMRT, or SBRT, the radiation therapists implicitly assume that they’re going to be treating the whole prostate.
Liz: [06:44] You mentioned there were a lot of bad side effects of radiation in the 1990s. What’s changed?
Dr. Scholz: [06:50] The greater accuracy is the biggest thing. Of course, if the radiation can be kept away from the bladder and the rectal wall, then the prostate treatment is not likely to have major negative implications. The prostate is not an essential organ unless you want to have babies. So that is the biggest difference. There are some other developments that have occurred, in particular this gel substance called SpaceOAR that can be squirted between the rectum and the prostate, pushing the rectal wall away from the prostate and outside the radiation field. So one of the frightening potential side effects of radiation that we faced in the past was a permanent, un-healing burn of the rectal wall, which was very painful. That problem, with the use of SpaceOAR and of course with more accurate targeting, now has been almost completely eliminated.
Liz: [07:42] SpaceOAR seems like a really big deal. When is it administered?
Dr. Scholz: [07:47] Anyone that’s undergoing radiation with any of these methodologies including people who are going to undergo seed implant radiation can potentially benefit by a SpaceOAR injection of gel between the prostate and the rectal wall. This is an outpatient procedure. The gel stays in place for about 90 days and then after the radiation therapy is completed, the gel automatically reabsorbs and disappears.
Liz: [08:14] This is something we’ve mentioned a lot, but not all doctors are up-to-date with the latest information. Is SpaceOAR something that most doctors are using now?
Dr. Scholz: [08:24] I’d say at the large university centers it’s becoming widely accepted but it is very new and there’s always an uneven uptake of new technology. Thus we try to have these podcasts and others are out there also trying to improve patient empowerment.
Liz: [08:42] One other thing that I think a lot of people are concerned about with radiation is if there’s residual radioactivity.
Dr. Scholz: [08:49] That is an issue with permanent seed implants and perhaps not nearly as big an issue as people want to make it out to be. Just like as if you have had a chest X-ray, you don’t walk out radioactive, when you undergo beam radiation, there is no residual radiation left in your body.
Liz: [09:10] Can you address some other side effects that might come with radiation?
Dr. Scholz: [09:14] The main issue for guys is the risk of erectile dysfunction. Depending on a man’s age, the risk can range anywhere from 25% to 80%. When I describe erectile dysfunction, the inability to get an erection, the issue in the prostate world is that the pills like Viagra and Cialis, Stendra, and Levitra simply don’t work. Most of the world, the normal world, thinks of erectile dysfunction as something you can treat with pills. This is correct, but not in the prostate world. If the doctor says that you have a 50/50 chance of developing erectile dysfunction, it means that even if you take a handful of Viagra, you still can’t get an erection. So, what do men do if they encounter that problem? Well, it’s not pretty. There are injections, there are implants, there are pumps, but all these things are really unnatural. Although they can be effective and one could argue that they’re better than nothing, they’re not a happy outcome. For example, if you take a healthy 60 year old man undergoing standard radiation treatment with any of these methods that we’re talking about and he hasn’t previously required any Viagra or Cialis, the risk of erectile dysfunction is probably around 40%. That is something that can occur within one to two years after the radiation is completed. The incidence of developing erectile dysfunction two or more years after the radiation treatment is the same as men of a similar age. So the risk of developing ED is in the first two years after radiation. If men get past that, their risk is the same as other men of similar age. So that is the biggest problem. Now, if you go to a quality center the risk of rectal damage should be minimal or non-existent. The other issue is related to urinary problems because the urethra passes through the prostate. A small percentage of men for whatever reason, possibly due to genetic issues, heal poorly after radiation. Men can be left with urinary frequency, urgency, getting up at night, common symptoms that occur for about a month after the radiation and go away in most everybody. A small percentage of men have ongoing issues that can last months or even years. That has become less and less frequent with better, more focused radiation, but the risk hasn’t been completely eliminated even to this day.
Liz: [11:56] Considering all those side effects, if we’re comparing radiation to surgery, it still has improved outcomes.
Dr. Scholz: [12:03] Yeah. That’s the way most things in the prostate world are. It’s all not a matter of “Is it good or bad?” but “Is it better than the other options?” People with prostate cancer that have the type that needs to be cured are going to have to do something. If you start listing the side effects of radiation, they don’t look so bad when you compare the list to what men undergo when they have surgery.
Liz: [12:26] One difference between radiation and surgery is that with surgery the prostate is removed and with radiation it’s still in the body. So, how are you monitoring for treatment success after a man has had radiation?
Dr. Scholz: [12:42] That actually one could argue is one of the few points of light for surgery. With the prostate out, the PSA should be undetectable. If it’s not then you need to go searching for why there are still some cancer cells somewhere. With radiation, you’re going to have a prostate gland that can cause the PSA to be somewhere like a 0.5, 0.8 and that’s normal after radiation. So unless the PSA starts rising above one or two, there’s really no reason to be looking further for the possibility of recurrent cancer. The trouble is that radiation, especially SBRT, seed implants as well, can cause delayed PSA elevations due to inflammation in the gland one to three years after the treatment creating all kinds of confusion. So now, of course, we’ve got new technology coming out called PSMA PET scans that allow us to go searching for possible recurrent cancer in men that have PSA levels that are misbehaving. In the past we had to sort of sit on our hands and wait patiently to see if the PSA would come down on its own. If not, then the process of treatment for relapse would be put in place and proceed. Now with these new, better PSMA PET scans, facing the ambiguity of a slight rise in PSA is not quite so challenging as it used to be.
Liz: [14:09] Say a patient has just had his daily therapy, about 15 minutes, and when he leaves the office, if he were to have a PSA blood test right then would his PSA be lower or does he have to wait for a little bit?
Dr. Scholz: [14:26] Yeah, the radiation, which is attacking the whole prostate gland, can certainly temporarily cause the PSA to rise. The usual time period after radiation is completed that we wait until re-measuring the PSA, to sort of see how well we’ve done, is about three months after the radiation is completed. So, PSAs done during radiation can jump around and really aren’t too terribly helpful in trying to figure out where your prostate cancer status lies.
Liz: [14:59] Okay. So men shouldn’t be concerned if their PSA doesn’t immediately drop.
Dr. Scholz: [15:04] Right, typically people are getting their PSA checked every three months after radiation is completed. When you look at decay curves or graphs of sequential PSAs plotted out over time, you could say that there’s a slow decline in PSA, oftentimes down to less than one within about a year to a year and a half after the radiation is completed. We don’t expect the PSA to suddenly plummet to zero, with radiation that would be very unusual. Typically people starting on radiation aren’t measuring PSA. The prescription is to start therapy and not take any holidays and move straight through the radiation and complete it on schedule. That’s the way it has been studied and that methodology is what yields the predictable cure rates that are associated with properly administered radiation.
Liz: [15:56] Okay, it seems like there are a lot of benefits to radiation. It’s not invasive, it doesn’t require hospital stay, there’s limited recovery time after treatment, it has great cure rates, and not a huge risk of long term side effects. What kinds of patients are eligible for beam radiation?
Dr. Scholz: [16:18] With prostate cancer, of course, we’re dealing with some types of prostate cancer that are harmless and don’t require any type of treatment. Just about all the other newly diagnosed men with prostate cancer are potential candidates for cure with radiation. There are, of course, some men that don’t do PSA testing and come in the door with PSA levels of 600 and metastatic disease. Those gentlemen, of course, are not candidates for cure. Pretty much everyone else, intermediate-risk prostate cancer, high-risk prostate cancer are probably best served with some form of beam radiation as we’re discussing, or possibly beam radiation plus seed implant radiation in combination.
Liz: [17:03] Other than Gleason 6, is there anyone that you would not recommend get radiation?
Dr. Scholz: [17:09] There’s some hesitation to give radiation to men who have a lot of difficult preexisting urinary symptoms, men that have really large prostates that are waking up three to five times at night already. The concern being that further irritation of the gland could make those symptoms even worse. So that argument is reasonable to consider. The trouble is having surgical removal of the prostate brings in all kinds of even more negative things. So while that could be discussed, just simply removing the prostate to “solve all the preexisting urinary symptoms,” that has to be weighed against the possibility of incontinence and the dangers of doing a major operation. That is the main concern of that being the possibility of increasing preexisting urinary symptoms to a point where they could become intolerable if the radiation irritates the urinary tract even further.
Liz: [18:09] Situations like that are why it’s so important to get second opinions. A lot of men take Lupron in combination with radiation. Is that a correct statement?
Dr. Scholz: [18:21] Yes, it is. The use of Lupron or other types of injectable hormone medicines or pills has been shown in a number of studies to make the radiation work better. If men have intermediate or high-risk prostate cancer, they’re often given Lupron for anywhere from four months to 18 to 24 months, before, during, and after the radiation. The use of hormone treatments of course, is complex. There are a lot of different types and there are certain situations where radiation can be used without hormone therapy. The majority of men who are getting beam radiation are getting some Lupron or similar type hormone treatment at the same time. This is to improve the cure rates, which have been shown to be better with a combination of Lupron plus radiation compared to radiation alone and choosing between IMRT, IMPT, and SBRT. In fact, in selecting any treatment option in the prostate cancer world, the biggest difference really lies in the talent of the provider. There’s a skill factor that far supersedes the actual equipment. That is one of the challenges in the prostate cancer world. Who really knows what they’re doing? I don’t have an easy answer for that. Multiple consultations, online searches, do the best you can, talk to support groups, try to find who’s really good at what they do because the outcomes will be better and the side effects will be less. Between these three, IMRT, IMPT, and SBRT, I think that the cure rates are going to be very similar. You’re talking mainly about a convenience factor, assuming the providers are equally talented. SBRT is given in a short time period, which is much more convenient than the other two methodologies. Whenever you’re planning on treatment for prostate cancer, please be sure that you’re talking to your doctor about how to prevent side effects. Side effects can end up being permanent, so you don’t want to be starting to solve the problem after the treatment. Remember the SpaceOAR gel, which is very effective at eliminating the risk of rectal damage from the radiation. This is a reasonable consideration with both beam radiation and seed radiation. On our next podcast, we’re going to cover the role of hormone therapy in much more detail than we did today. There are other situations where men need hormone therapy without radiation. So we’ll cover that in our upcoming podcast.
Liz: [21:03] Remember to send any questions or topics of interest to firstname.lastname@example.org. Also, please help us out by rating, reviewing and subscribing to PROSTATE PROS on Apple Podcasts and by sharing the podcast with your friends and family.