Is Proton Pencil Beam an option for salvage radiation of a tumor located in left seminal vesicle and extending to rectum wall?

[Coastguy]

A recent C T guided biopsy at OHSU was positive for recurring prostate cancer. Both NIH and OHSU radiation oncologists have ruled out SBRT because of the tumors location. Has anyone in this group been treated for prostate cancer recurrence with Proton Pencil Beam? I’m 76 years old, very active, and otherwise in excellent health. I have delayed starting any type of hormone therapy because quality of life is very important to me and all previous scans had been negative. If this is not an option, I am planning to start 150- mg Bicalutamide monotherapy along with 10 mg of tamoxifen to reduce my PSA which is now 57.1 having increased from 34.7 in April when I was at NIH for the latest scan. Your thoughts please. Thank you.

[timotur]

CG: Your dx is very similar to mine with left-SV and possible-rectal wall involvement (details in my profile). My primary ongoing treatment is HDR-BT + 41Gy EBRT + 18mos HT. Per my Onc, HDR-BT is the preferred rad tx for SV involvement (over LDR-BT and SBRT). However, I'm not sure HDR-BT can be done as a salvage to your first Proton tx in 2008, but I would ask about it. Best- Tim

[Coastguy in reply to timotur]

Thanks Tim. I will follow up.

[GP24]

I had fiducials placed into the affected seminal vesicle before the SBRT salvage radiation. This allowed to radiate it with SBRT.

[Tall_Allen]

It sounds like the issue is that the tumor may have penetrated the rectum wall? If so, they may be worried that any kind of radiation or ablation may cause a fistula. Your idea of starting with hormone therapy sounds reasonable - why not shrink it first and see what you can do afterwards?

[Coastguy in reply to Tall_Allen]

Thanks T A. The NIH docs did not encourage me to get a biopsy and said thru the coordinator that I was not a candidate for their SBRT trial. The OHSU radiation oncologist concurred when asked by his nurse. A colonoscopy in early January showed no problems. The proton Pencil Beam is very precise and with the Bragg effect, I thought it might be an option. The OHSU doc who performed the C T guided biopsy went thru the left buttock and had no trouble getting the sample. Waiting for a consultation with the Maryland Proton Center ( I have a sister who lives in Baltimore). Can’t start the bicalutimide monotherapy as I’ve not received my tamoxifen prescription. Will let you know what Maryland Proton Center thinks.

[Tall_Allen in reply to Coastguy]

The Bragg Peak is a fine theory that doesn't play out in practice. There is always collateral damage. Read this:

pcnrv.blogspot.com/2016/08/...

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What TA said about shrinking the tumor first is exactly what MDA did with me. I had the tumor against the rectum. They took 8 months To shrink the tumor with Zytiga and lupron. It worked in shrinking the tumor by 2/3 which showed it pulled away from the rectum. Then with the proton pencil beam they did whole pelvis radiation. They cooked my rectum telling me I might have the issues TA discussed. I said turn up the beam and get it done. Dr Shaw at M D Anderson.