Proton Ambassadors:
Don’t Retire Yet

Ron Nelson

Yesterday I watched a replay of a very recent live webinar hosted by the excellent UsToo prostate cancer support group chapter in Greenville, SC. The speaker’s main objective was to describe a relatively new product known as SpaceOAR, an innovation now used in prostate cancer radiation therapy—both photon and proton. He prudently disclosed his non-monetary relationship with Augmenix, SpaceOAR’s parent company, and did a very good job describing their product.

The presenter was Daniel Fried, a radiation oncologist specializing in prostate cancer radiation, among other things. He is expertly knowledgeable about SpaceOAR, and his presentation was very useful and much appreciated. I watched the replay with great interest, and learned a few things about SpaceOAR I did not already know. If you’re curious and have an hour, it’s worth watching.

Of course, as a blogger I watched with a critical eye and noticed a few things needing clarification. So clarify I will.

Is the balloon dead?

Dr. Fried began with some relevant history, which was generally helpful. However, by including the rectal balloon on the timeline, I was left wondering whether the balloon is in fact, history. He doesn’t state that the balloon is dead, but we are allowed to infer that SpaceOAR has made the rectal balloon obsolete. But is it?

… we are allowed to infer that SpaceOAR has made the rectal balloon obsolete. But is it?

SpaceOAR is a two-part gel injected via the perineum into the space between the prostate and rectum, a one-time procedure done before treatments begin. Rectal balloons are inserted into the rectum prior to each radiation treatment and removed after each session. Either method can be uncomfortable, but they are usually well-tolerated.

Both methods are still in use and have overlapping objectives. The primary job of SpaceOAR is to protect the rectum from unwanted photon or proton radiation by creating a temporary space (filled with hydrogel) between the prostate and rectum (Space between Organs At Risk). Secondarily, it applies pressure to the prostate to help reduce its tendency to move around during treatment. In contrast, the primary job of rectal balloons is to help immobilize the prostate. A more stable prostate allows treatment of smaller margins, which in turn reduces—but does not completely eliminate—overall exposure of the rectum to radiation.

The balloon works great, and time will likely confirm our expectation that SpaceOAR works even better. But it’s great versus better, not bad versus good.

Fried shows several comparative charts to support the benefits of SpaceOAR. While I acknowledge the benefits, I doubt if anyone noticed that his comparisons of subsequent side effects compared SpaceOAR versus nothing, not SpaceOAR versus balloons. If we were to compare balloons with nothing, they’d look pretty darn good, too. And they are. And so is SpaceOAR.

Why choose the balloon?

Given the choice, I’m sure most men (despite folklore to the contrary) would prefer to avoid the balloon. It’s really not bad, but surely doesn’t sound good compared to a one-time seemingly simple, relatively short procedure. So what’s the problem with implying the demise of the balloon? Isn’t this likely going to be the case soon enough, anyway?

I’m sure most men (despite folklore to the contrary) would prefer to avoid the balloon. It’s really not bad, but surely doesn’t sound good …

The fact is, the balloon is still in use, and will likely remain so because SpaceOAR is not perfect for everyone. There are circumstances that can disqualify a man from using SpaceOAR, and this was not mentioned. Pre-existing urinary issues, an enlarged prostate, insufficient room between the rectum and prostate, and other disqualifiers can rule out the hydrogel. There are also times when the gel is injected, fails to perform as needed, and the balloon must be used after all.

It’s important to know this for the following reason: If I had heard this presentation, and if I were about to receive radiation for prostate cancer and was told the balloon would be used, how would I feel? I’d likely be concerned and upset if what I believed to be an inferior, outdated, ineffective technique was being forced upon me. I might be unnecessarily angry, worried, and left wondering what side effects I’d experience because of being denied SpaceOAR. Again, Dr. Fried never actually said the balloon was ineffective, but he may have unintentionally created the false impression that it has become antiquated.

There is no need for any man to feel anxious about poor results when the balloon is used.

There is no need for any man to feel anxious about poor results when the balloon is used. Neither SpaceOAR nor rectal balloons are perfect. Neither can guarantee you’ll have no side effects. Neither can be used in every case. And both do their jobs well. The rectal balloon has been used with very good results for many years, and SpaceOAR promises even better results in the years ahead. Either way, you’ll probably be just fine.

Personal Disclosure:

In 2011 I was treated for prostate cancer with proton therapy and rectal balloons. If given the choice today, I’d forgo the pleasure of the balloon, and would happily eliminate that chapter in my book. I feel confident I could write a good chapter on being a gel guy rather than a balloon boy.

Is SpaceOAR for x-ray radiation only?

I was disappointed that there was not even one reference in this presentation that SpaceOAR is actively being used with proton therapy, as well as with photon. In fact, proton therapy was not mentioned at all—indeed, SpaceOAR was the topic—until a question was asked about it during the Q&A at the end. Sadly, it is hardly uncommon for oncologists and urologists to ignore proton therapy. But it exists, it’s available, it’s time-tested, it’s cutting edge, it works, and it has unique characteristics and benefits. Surely proton deserves at least an occasional mention.

Dr. Fried should be enthusiastic about proton radiation for the same reason he likes SpaceOAR. They both undeniably reduce the exposure of healthy tissue to radiation.

Ironically, Dr. Fried should be enthusiastic about proton radiation for the same reason he likes SpaceOAR. They both undeniably reduce the exposure of healthy tissue to radiation. He describes how data and common sense support the hope that SpaceOAR will be at least somewhat more effective than balloons in protecting the prostate. Well, the same logic applies to proton therapy. It exposes no radiation at all to healthy tissue beyond the target—unlike x-rays which radiate everything in their path. Isn’t proton therapy plus SpaceOAR the most exciting combination of all?

Certainly, SpaceOAR can be beneficial when used in conjunction with photon radiation—IMRT. For precisely the same reasons, we’d expect SpaceOAR to provide similar benefits with proton radiation. Indeed, it is currently being used with both photon and proton—which is at least worth mentioning.

Is proton worth exploring at all?

As a proton guy, I would have liked to have given the answer to a question submitted during the Q&A after the formal presentation. Someone viewing the webinar live via the internet asked for a comparison of photon and proton. I would have described the essential difference succinctly: Photon radiates everything in its path—before, at, and beyond the target. Proton deposits less radiation on the way to the target, maximum radiation at the target, and none beyond it, resulting in less radiation of the surrounding healthy tissue.

When broader coverage is needed, photons may be best. When greater precision is needed, proton is likely a better choice.

I’d have added that this doesn’t make photons bad and protons good. It makes them useful in different situations. When broader coverage is needed, photons may be best. When greater precision is needed, proton is likely a better choice. In fact, there are even times when the two are used with the same patient. The more tools in the toolbox, the better.

The 3-minute answer given was quite different. I have transcribed it word-for-word for your convenience below. In case you want to hear it from Dr. Fried, you can click here to jump into the video at that point.

Okay, so … photons versus proton, so … photons are essentially x-rays. Now, x-rays are what we most commonly use to treat … what we’re using radiation therapy. When people talk about radiation therapy and they don’t make any other distinction about what it is, they are talking about photons. This is what when people talk about a linear accelerator, or a radiation producing machine, they are talking about photons.

Over the last couple of decades there has also been a growth in the use of something called protons. Now, protons are different from photons. It’s also radiation, but this is using a different form of radiation. There are only a few centers in the country that do protons … actually that number is growing as the cost of proton centers has come down.

In the treatment of prostate cancer, we, there have been a number of studies now looking at photons versus protons and asking the question, well, is one better than the other. And the contention had never been that they would cure cancer differently, and in fact I think we see from all the studies that they work equally well at controlling cancer, but the contention was that protons, because of how they interact with tissue … and I won’t get into the specifics of that … but because of how they interact with tissue, would cause less damage to normal surrounding structures.

But it turns out over a bunch of studies that have looked at this over the last several years that there seems to be no difference in the rate of side effects or toxicity for protons versus photons, and in fact what we’ve seen, is in terms of reimbursement, that protons used to reimburse about three times as much as photons, but now that has come back down, so that protons are reimbursing fairly similarly to photons, because insurance companies and Medicare know the data that basically states that there’s not a big difference between the two as far as their ability to protect the normal structures.

Lasting impressions

To be fair, Dr. Fried was invited to talk about SpaceOAR, not proton radiation, and he did a good job. The question about proton was tossed at him in the Q&A, and he took a reasonable stab at it. Had he been prepared to talk about proton radiation, I’m sure he would have answered more eloquently. From personal experience, I can vouch for the fact the Q&As are the most challenging part of any presentation.

Nevertheless, I asked myself what impression I would have been left with, had I been in attendance, and had I been relatively unfamiliar with proton therapy. I would have heard only that “protons are different than photons,” but no better. And that’s about it.

I would have liked hearing about the benefits of proton therapy in not only prostate cancer, but other adult and pediatric cancers—brain, eye, lung, throat, breast, pancreas, etc.

I must remind myself again that it was not a proton therapy presentation. As much as I would have liked hearing about the benefits of proton therapy in not only prostate cancer, but other adult and pediatric cancers—brain, eye, lung, throat, breast, pancreas, etc.—simply wouldn’t have fit the topic. Still, hearing “no difference” in the Q&A would have left me feeling that proton radiation is a pointless aberration of real radiation, and not worth consideration for treating any cancer—far from the truth.

The question of how proton compares to photon is a good one, and the difference should be understood. Merely stating it is “different” leaves too much unsaid, and the implication that it is “no better” than photon radiation is unfortunate. There are many cancers that cannot be treated by photon radiation at all, yet are very treatable with proton therapy. People need to know this, and not be led to infer that proton is irrelevant.

There are many cancers that cannot be treated by photon radiation at all, yet are very treatable with proton therapy. People need to know this …

What remained unsaid

In addition to the above, there is a plethora of information about proton radiation therapy I might have offered in those three minutes had they been mine. I would have described how photons distribute radiation along their path from entry to exit, as compared with protons, which radiate nothing beyond the target. I’d have mentioned the Bragg Peak, and included cyclotrons along with linear accelerators as examples of radiation producing machines.

Explaining a bit about why, despite obstacles, proton centers are proliferating in the U.S. could have given insight into the thinking of the leaders of those facilities. Clarifying that Medicare, Tricare, and some other insurers do at least sometimes cover part of the cost of proton therapy would have given it validation. And admitting there are many people and studies supporting the benefits of proton therapy for prostate cancer would have provided a welcome objective perspective.

In any case, I suppose it is true enough: proton is “different.” With benefits.

Beware of hidden messages

My intention here is to clarify the above issues, and to remind all patients—past, present, and future—that even in the most excellent presentations and publications, we must remain vigilant in our skepticism of any vague or unsupported statements, and we must hunt for those. They are not easy to spot. They may be tucked away between the lines of a clear and authoritative narrative, and often sound at least superficially convincing.

we must remain vigilant in our skepticism of any vague or unsupported statements, and we must hunt for those. They are not easy to spot.

This blog post will not be read by all members of the webinar audience, and the presentation will stand as-is. Today, the webinar replay has only 440 views, but the number will inevitably increase as it remains online for many years. As it does, the good information about improvements in prostate cancer radiation will spread along with the unfortunate and probably unintentional misrepresentation of proton therapy.

So proton ambassadors, take note: Your job is not done. You cannot retire from promoting awareness of proton therapy. Sadly, it is still in many ways a best-kept secret. Patients—both adults and children—who could benefit from proton radiation may not even know it exists unless we remain dedicated to educating them about it and urging them to at least consider it. So no, I’m afraid you can’t turn in your badge just yet.

I heartily thank Johnnie Payne, the dynamic leader of the Greenville UsToo chapter, for hosting the webinar. I sincerely thank Dr. Fried for his informative presentation on SpaceOAR. I thank the creator of the internet for providing me with the opportunity to clarify a few things. And thank you for taking time to read my article.

What’s your opinion about Dr. Fried’s SpaceOAR presentation? Email me!

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