Thoughts on Proton Beam Therapy

[BTExpress]

Any good or bad experiences?

[stangoldberg]

You might be interested in an article I wrote about proton beam therapy in South Korea. In summary, the statistics are still equivocal regarding which form of therapy is best for each person.

stangoldbergwriter.com/abou...

[Neathuh1 in reply to stangoldberg]

I just saw an article that said at 2 1/2 years post proton therapy and 4 years post IMRT that there were no differences in genito-urinary or gastro-intestinal side effects. Still, the proponents of proton therapy do believe it has less side effects.

[PhillyProstate]

I've met a few proton beam guys during my prostate cancer journey. They seem Very enthusiastic...almost religious. But when you drill down with them, their erectile functioning and urine control is no better or worse that guys with regular radiation.

[AlanMeyer]

My Gleason 7 prostate cancer was treated, apparently successfully, 12 years ago with x-radiation (HDR brachytherapy + 3DCRT external beam + Lupron.) I have no experience at all with proton beam therapy (PBT), nor am I any kind of a doctor. So what follows are some thoughts by a totally unqualified person - to be listened to at your peril.

It appears from my reading that PBT and x-rays work in somewhat similar ways. They both deliver high energy to the tumor cells, energy that damages some of the molecules in the cells, for example by knocking electrons off atoms (by electromagnetic interactions), causing those atoms to become positively charged, which causes them to interact and change, which, over a possibly quite long period of time, causes them to die. The difference between the two therapies is that PBT uses very fast moving protons to deliver the energy while x-ray treatment uses high frequency electromagnetic beams to deliver the energy.

I have not seen any claims from PBT practitioners that their treatment is any more effective than x-rays, only that it has fewer side effects.

Theoretically, the proton beam treatment was thought to have fewer side effects on tissue outside the prostate. The reason has to do with something called the "Bragg Peak" (q.v. Wikipedia) In theory, PBT can be tuned to deliver energy to the prostate with very little energy delivered before or behind the prostate. X-rays don't work that way. They tend to deliver high energy at the surface of the skin, gradually diminishing as the rays go through the tissue, through the prostate, and through the tissue on the other side. Damage to tissue outside the prostate has to be controlled by aiming the beams to avoid other sensitive organs, and by moving the beam emitter to send beams from different directions focusing on the prostate - so only the prostate gets all of the beam energy.

So far so good and, theoretically, PBT has an advantage in having fewer side effects, but here's the rub. At least some of the studies of real patients haven't found such an advantage. I seem to recall seeing studies that showed PBT had fewer side effects, studies showing it had more, and studies showing no difference.

I think one reason for this is that a lot of the undesirable effects of radiation are not caused by damage outside the prostate, but by damage to the prostate itself, and both techniques do that. Another problem, apparently, is that the energy level and aiming can't be 100% precise using current techniques. Another is that protons can scatter after hitting things, causing some damage outside the target zone.

Finally, energy can be confined close to the prostate with x-rays too by using brachytherapy.

So, if I were making the decision for myself, I'd be guided more by my confidence in the radiation oncologist than by whether protons or x-rays are used. I'd want someone who has a LOT of experience treating prostate cancer, who appears to be thoughtful, careful and committed, who is keeping up with the latest research, and who has a good staff to help.

As for surgery vs. radiation, that's a whole different comparison. I have unqualified opinions about that too, but the only one I'll express here is that I'd rather be treated by a top surgeon than a run of the mill rad onc, or by a top rad onc rather than a run of the mill surgeon.

Best of luck.

Alan

[maack1]

news.yahoo.com/no-fewer-sid...

No fewer side effects for prostate proton therapy

By Trevor Stokes | Reuters –

•

NEW YORK (Reuters Health) - An expensive prostate cancer radiation treatment known as proton beam therapy has just as many side effects as a more common and cheaper radiation method, according to a new study.

In terms of side effects, "In the long term, there's really no difference in outcomes between proton radiation and IMRT for men with prostate cancer," said lead author Dr. James Yu, a radiation oncologist at Yale University School of Medicine in New Haven, Connecticut.

Proton therapy advocates argue that protons blast radiation directly to the tumor and therefore avoid side effects. The more common "intensity-modulated" radiotherapy (IMRT) exposes some healthy tissue to radiation that researchers hypothesized would increase side effects and even additional cancers.

After a year, however, the study found the same number of side effects among men who'd had both treatments.

Prostate cancer, the most common cancer in men, kills about 28,000 Americans each year. However, many men don't die of the disease, because many tumors grow very slowly.

Treatments include chemotherapy, hormone therapy, surgery, and frequent surveillance - aka "watchful waiting."

Although researchers are at odds over which treatment - proton therapy or IMRT - is the better option for men who choose radiation, that hasn't stopped the growth of proton beam centers. There are ten such centers in the U.S., according to the National Association for Proton Therapy, with eight more under development or being built.

Each one can cost more than $125 million, and Medicare pays doctors about twice as much for proton therapy.

For the study in the Journal of the National Cancer Institute, researchers tracked Medicare claims in 2008 and 2009 for treatment-related complications in nearly 28,000 men with prostate cancer for up to a year. Only two percent of the prostate cancer patients underwent proton therapy and the remainder had IMRT.

After six months, nearly 10 percent of IMRT-treated patients, and six percent of proton therapy patients, had side effects including incontinence, a burning sensation while urinating or difficulty getting an erection. However, the difference disappeared a year after treatment, when nearly one in five patients suffered side effects regardless of which radiation treatment they had.

Yu and colleagues found that proton therapy costs nearly twice as much: $32,428 per course of treatment, versus $18,575 for IMRT. That difference was consistent with that found in other studies.

"The ball is in the court of the proton folks in terms of proving a benefit," Yu told Reuters Health.

The study only looked at side effects, and did not compare the effectiveness of the treatments, which proton therapy advocates said was a significant weakness.

If Yu is "willing to make recommendation or clinical judgments based on this sort of data, I think he's at risk to doing a disservice to his patients," said Dr. Andrew Lee, director of the Proton Therapy Center at the University of Texas MD Anderson Cancer Center in Houston. "It's like trying to read a license plate from 30 thousand feet up in the air."

Lee, who was not involved in the new work, said that the study's length - a year - wasn't enough time to look at the full scope of side effects from either treatment. The study also failed to include side effects that didn't require a hospital visit, and couldn't say how long treatments lasted.

Proton therapy isn't for everyone, both noted. Lee said the treatment was best for young healthy patients, while Yu said it is most useful for cancers in children or in sensitive areas where minimizing the radiation is critical.

Yu would not recommend it for prostate cancer.

"The cancer center next door or the radiation oncologist in the community will likely do just as good a job at treating prostate cancer with IMRT as a proton center three times out of the way," Yu said.

SOURCE: bit.ly/V6PkLT Journal of the National Cancer Institute, online December 14, 2012.

[AlanLawrenson]

I had PBT in South Korea in early 2013 for my prostate cancer. Their National Cancer Centre claims to be the best cancer clinic in the world. I live in Sydney, Australia. I am still remission with normal QOL.

If I was being treated now, I'd probably have mpMRI to clearly identify size and position of tumours, followed by Focal Laser Ablation of the prostate. I wrote a very successful book on my Journey.