Final decision on treatment: Viewray or Truebeam?

WOW, a Decipher low risk of 0.26 ? That's better than mine at 0.37. According to Decipher, Low Risk means you and I are perfect candidates for Active Surveillance (AS). I just had a consult with a medical oncologist for a second opinion at a major hospital in Wash, DC. He said I was at such a low risk that I should not even consider any treatment options for now and concentrate on closely monitoring my PSA which is at 3. The schedule for PSA tests would be a minimum every 6 mos and a maximum of every 3 mos. If the PSA were to get up to say 8 or higher, then he would take a closer look at things. Be sure to read this article on the internet using the following Search terms "Study finds prostate cancer treatment can wait for most men". Keep in mind that prostate cancer cells grow VERY slowly in about 80% of men so time is on our side. I hope you read this before you go under THE BEAM !

With all the protons passing through opposing paths 180 degrees, You get more concentrated energy along the path. The role of the Bragg effect is negated when the two beams contribute on both sides. With automatic gating, smaller margins & adaptive planning the dose received by OAR is likely less than with the proton. We can't know the actual dose with proton as structures move and can move OAR into the beam depositing more energy in the bladder or rectum.

Although we can theorize that one method is better than another, the only randomized data we have shows reduced side effects with MRIdian. Until there is real evidence as opposed to marketing hype, I'd lean to MRI guided 5 treatment SBRT, than 45 CT guided proton with larger PTV margins and no protection during movement.

I think you intended to say "Proton has all the energy through only two paths." What I want to know is whether the Photon radiation is controlled by MRIdian so that it does not escape outside of the prostate when the beams are turned ON? From what I've read, Photons (xrays) pass right thru tissue and don't stop until they leave the body. What is your understanding as to what is going on when treatment is being applied ?

I think men are finding better information regarding the risks of surgery that occur immediately. They are learning about penile shortening, ED and incontinence. The advances in RT have been non stop. ROs are learning how to reduce side effects. Hopefully we will soon see adaptive radiotherapy and automatic gating which will improve safety and side effects profiles to all delivery systems.

Great summary. Although I chose 5 treatment proton at Mayo Rochester where they use Hitachi kit, the statement, "There are no well designed randomized studies comparing proton with photon" is consistent with all I have read and been told by urologists and radiologists. The one statement made by those perfming the procedure that I question is whether Radical Prostectomy is still the "Gold Standard". Photon and Proton have been shown to have equal long term outcomes.

rockin2047: one of the great benefits of the Mridian is real time MRI mapping and dynamic mapping capabilities. I had an MRI and a CAT scan used for preliminary mapping. They were used as a guideline for the initial set up and the real time Mri in the Mridian was used to finalize the mapping. They did not have to use the dynamic planning capabilities of the Mridian as my body did not move internally or externally in a way that required it but it was there if needed. In other types of cancer, where the organs move more, the dynamic planning capabilities of the MRIDian become more important.

I had a PET scan but mapping was MRI and CT.

ViewRay is photon. The issue also has to do with how many beams. MRIdian has up to 18 beams, energy divided into 18 paths. Photon has all the energy through only two paths. As a result there are more skin burns with proton. Proton also adds 5 mm margins around tumors, MRIdian adds 3mm so less normal tissue is exposed with MRIdian. Adaptive radiotherapy and automatic gating significantly lower the risk of side effects with MRIdian which is about 50% less than other CT guided radiotherapy. There are no well designed randomized studies comparing proton with photon. No evidence that 45 proton sessions will do better than 5 with MRI-Linac.

Am glad to read about your experience with ViewRay's MRIdian SBRT. I am considering using this 5 treatment option as well. My understanding is it combines a high tech MRI with proton radiation. However, jackm9005 just replied to me saying "I recently had my consultation and was told that protons are not delivered using the Mridian ViewRay, only photons. Has something to do with the magnets in the MRI and protons." So, what did you receive protons or photons? The clear definition I found was "The key difference between the two in terms of radiation therapy: Like an x-ray, photon beams will pass through the body and have an exit point, whereas protons can be stopped in tissue without a significant amount exiting the body." Who wants to have an exit dose of photons passing right thru the prostate and beyond? Hopefully you will tell me you had protons.
What did they use to map you, an MRI scan, a CT scan or a PET scan?
If I have two GL 3+3 and a GL 3+4 do you think all three could be zapped in 5 treatments?

See my comment below about my 5 proton treatments at Mayo Phoenix. Other than my five inch tan circles on my hips where the radiation entered, I would not even know anything was done. I did have the SpaceOar Gel inserted. I still wonder if they did give me the correct dose as I expected at least some side effects.