COMPPARE that tests proton radiation against photon IMRT radiation.

the improvements in focal radiation in the last <10 yrs show that the photon shaped beam is almost identical to proton beam in accuracy with very little radiation splash from the photon beam machines. In some cases, some radiation splash may indeed suppress cancer cells lurking outside of known areas of cancer in prostate and surrounding tissue/lymph nodes. in years passed, lymph node radiation was risky business and almost always caused radiation burn to surrounding tissue. Not so today.

The best delivery systems are made by Varian /Seimens .
(Varian -Siemens Healthineers): The undisputed market leader in standard and adaptive radiotherapy. Their TrueBeam and Ethos systems use built-in 4D imaging and AI to reshape and target radiation beams in real-time while patients breathe. Varian uses both photon and proton beam technology- Proton Therapy: Systems like the ProBeam use accelerated proton particles rather than photons. Protons are heavier, charged particles designed to stop exactly at the tumor site, minimizing damage to tissues and organs located behind the tumor.

Elekta: A major innovator in precision oncology and MRI-guided radiation. Their Elekta Unity integrates a linear accelerator with a high-field MRI, allowing doctors to see soft tissue and adapt the radiation plan in real-time during the procedure.

So the myth is busted. Radiation proctitis has been the worse part of my 4 year journey hands down. Going on 15 months with it. Treatment has helped and will be checking in for pelvic floor work with a Pt.

Thanks for posting this. Looking at this and similar articles shows proton is not the panacea that many make it out to be. Likely a more important factor is the skill of your RO and their team. Much of the photon hype is market driven as they attempt to recover the enormous installation costs.

It would have been interesting to see a comparison between Proton and SBRT using the Mridian or Elekta Unity MRI based photon. The smaller margins make a difference in side effects, per the Mirage study, but no study that I have seen on Proton VS MRI Guided radiation.

Wouldn't it make a difference that Proton does not exit the body or damage other tissue or organs because it stops at the treatment site? I would think not to have radiation affect other parts of body with exit dosage would help preventing a different cancer years later. Even with very small margins MRI or CT guided Photon the radiation still has to exit the site / body?

@xahnegrey40 “… focal radiation in the last <10 yrs show that the photon shaped beam is almost identical to proton beam in accuracy…” is true. But how many men ask for that photon machine and how men centers have that available?

The two recent studies that are usually referenced are COMPPARE and PARTIQoL. Both studies indicated similar tumor control rates and patient-reported quality of life outcomes.

What’s important to understand about clinical trials is that they’re great at providing a “big picture” large population view of what to expect from treatments. Since they represent thousands of patients, insurance companies need that, hospitals need that, governments need that, etc., because they all need to plan and estimate how to allocate resources (dollars, equipment, staffing, etc.) based on the averages……not the best; not the worst.

But for what a specific patient (you or me) should expect our outcome should be from a particular treatment, they’re nearly worthless - without knowing how someone with a specific diagnosis, risk factors, comorbidities, regimen compliance, etc. compares to ours. (That applies to all clinical trials, not just these two.)

In my case, I didn’t just go by the no better/no worse large scale outcome. I selectively picked one of the 49 proton centers specializing in proton for my treatments - as it turned out a pediatric center (and a teaching and research center) that also treated prostate cancers (as well as other types) - because I knew that they were experts on hitting pea-sized tumors within the brains of kids without causing peripheral damage; I figured that they could hit a walnut-sized gland within my pelvis, also without causing peripheral damage. But, that also required me to do my part exactly right each and every session exactly the same way (& if I had screwed up, that would’ve caused problems).
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Today, 5 years (& 3 weeks later), it’s turned out as well as planned (if not better) - certainly better than either COMPPARE or PARTIQoL indicated that I should expect. But, that required me not shooting just for “no better/no worse” - which was the result of both those two studies.

@copyman It should. I have read in a number of places that proton radiation is considered generally superior for other solid tumor cancers. So, one must wonder then “Why not for prostate cancer?”
> are the laws of physics different?
> is prostate cancer tissue different?
> do the treatment centers all not do the calculations the same? (That has happened by the way.)
> is patient compliance an uncontrolled variable in these studies?

This requires some explanation as to why prostate cancer is different from other solid tumor cancers?

The application of proton radiation wasn’t discovered in the medical community for treating solid tumor cancers; it was discovered in the scientific/physics community, and they discovered that these heavy subatomic particles with wavelike properties acted differently than photons (x-rays).

It was the physicist William Bragg who discovered that protons deposit most of their energy right before coming to a stop, which is key to modern proton therapy for treating solid tumor cancers - they can pre-determine where exactly the proton releases its energy.

So, this is not a “theoretical” advantage. This “Bragg-Peak characteristic” (as it’s called) is a proven advantage over photons in the scientific community that later, someone said “Hey, maybe we can apply this in treating solid tumor cancers in order to reduce the entry-dose, scatter, and exit-dose that is inherent with photon radiation?”

These studies are alluding/concluding that science/physics is wrong; that the entry-dose, scatter, and exit-dose of proton & photon is similar. That requires explanation.

@brianjarvis What the PARTIQoL study did was shut down most insurance reimbursement (including Medicare Advantage but not classic Medicare) for proton treatment of prostate cancer. Medicare just started a precertification demo to lower cost on overused / unnecessary procedures. That may cut off Medicare proton funding for prostate cancer within 5 years if that gets expanded. Most proton facilities do a lot of head /neck and pediatric cancers because insurance will pay for them because proton treatment has been shown to be superior in trials vs. photon.

The fact that photon and proton treatments show comparable outcomes does not negate the laws of physics. It just means that the scattered photon doses from the latest machines are not doing enough biological damage to be measurable, at least not with the methods and time frames in these studies.

@jim18 I was part of a similar study (that my RO indicated my participation in was covered by Medicare), my treatment results being submitted into a registry (https://clinicaltrials.gov/study/NCT02040467) and followed for 10 years. (That probably explains why, now 5+ years later I’m still getting full bloodwork tested (CBC, CMP, & testosterone) with every PSA test.)