Final decision on treatment: Viewray or Truebeam?

My Decipher test came back as low risk. However two different radiologist/oncologist both stated the curative radiation therapy was warranted. I am in my 4th week of a 6 week M-F treatment plan for pencil Proton Radiation.

I agreed with radiation treatment. My bone scan was negative and my pet scan was negative. I was told cancer confined to prostrate. For me curing cancer not letting it grow was much better mentally than worrying about it growing outside of prostrate. The wait and see option was never presented to me even though my Decipher was "low risk." They did say my Decipher contradicted the biopsies which the worse ones were 4+3=7.

This Mayo Clinic Connect is a great source of information. I am glad that Mayo Clinic set it up. What I see though is still the disagreements withing oncologist/radiologist about photon and proton. I hope more studies are done to help patients have the information to make decisions. And maybe someday there will be a scientific consensus among radiologist/oncologist of what is best for patient cure and not personal opinions and bias.

I keep reading about Meridian and others having proton but only 5 treatments. I have a ICD/Pacemaker so the physics department at my Proton provider recommended pencil beam.

Wish I knew more about Pencil Beam. My question and maybe some of you know is when you get Pencil Beam does one beam come down or is there a multitude of beams? If entire prostrate is being treated how do you get pencil beam to all? When you say pencil beam you think it is a single beam the size of a pencil. That would seem like there would have to be hundreds of pencil beams.

Starting MRIdian next week at Dana Farber/Brigham & Womens in Boston.
5 treatments over 2 weeks.
Any experiences with this type tratment?

GL 4+3 is intermediate unfavorable which gets the PET ordered or should. Not sure what you mean by Gleason 20??

I was part of a PSMA PET study at UCLA and chose to push for it.

Do you recall what your Gleason number was? Perhaps 20 or higher which caused a PET to be done for you?

PSA was 0.3 when PET was positive. It is CT so yes the resolution is much greater with MRI, but the PET is far more sensitive because the radioactive tracer binds to PSMA on the cancer cells surface.

Your case is interesting. On the one hand you say "to get a PET scan which showed involvement just outside the gland in the seminal vesicle which didn't show up on MRI or CT scan." However, on the site health dot costhelper dot com it says "PET scans do not show images as detailed as those produced by a CT scan or MRI, but can show chemical activity and blood flow as other scans cannot." So was the involvement detected as a result of the chemical activity/ blood flow only? Please say what your PSA was at that time. I've read that there are 2 things that would require a PET scan: a PSA blood level of 20 or higher or a Gleason grade of 7 (3+4) or higher puts you at higher risk of metastatic prostate cancer. So was your PET scan because of a Gleason 7 and/or a PSA of 20 or higher or both?"
My PSA is only 3 but have one Gleason 7 (3+4) along with a Decipher Low Risk of 0.37. Thus I wonder if a PET might be done since my Gleason is a 7. Any thoughts?

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.