Cancer is back after Cyber Knife

Vic, but see the risk increase for doses <40 Gy found in the MSK study (added in my post above). Looking at the number of men for each dose, the majority received 40 Gy.

The ideal dose for SBRT is still being worked out.

Djin

Post Edited (DjinTonic) : 6/7/2022 9:57:28 AM (GMT-6)

Vic, I've labeled that data to make it clearer. Those are the number of men who had each SBRT dose.

Djin

From the paper's Discussion:

"Our findings highlight the importance of using higher SBRT dose levels, which are associated with improved local control as demonstrated on routine post-treatment biopsies. Patients who received >=40 Gy had a significantly lower rate of a positive biopsy compared to those who received lower radiation dose levels. The prognostic significance of a positive post-treatment biopsy after definitive prostate radiotherapy is well-recognized. Post-treatment biopsy data from several cohorts of patients treated with external beam radiotherapy indicate that residual prostate cancer cells are seen at 2–3 years after completion of therapy in 20–40% of men clinically without evidence of biochemical or clinical recurrence [11,12,14]. "

Vic, I'm not familiar with nanoknife. I see online that it is "ablation procedure that uses low energy electrical pulses to create defects (pores) in cell membranes, resulting in loss of homeostasis and subsequent cell death"

Is the whole prostate treated, or are only lesions identified by imaging treated?

Thanks,

Djin

Post Edited (DjinTonic) : 6/7/2022 10:10:14 AM (GMT-6)

Vic Hardy said...
I believe it is not whole prostate but areas with lesions. If I get a chance to talk to Dr. Coleman at Sloan I'll be sure to ask those questions. It apparently has no SE but I've read that recurrence in a couple years has happened.

My hunch is that it avoids additional radiation at the risk of not treating areas that could have unidentified microlesions. In other words, risks similar to primary focal treatment.

Djin

@Vic, Yes my PSA post treatment PSA has been bouncy and my RO and team remained confident it was simply a bounce. At 14 Mo. 1.8, at 20 Mo. 2.7, at 26 Mo. 1.0, at 32 Mo. .3. Currently I’m five years post treatment and plan my next PSA in August with a Nadir of 2.3. They estimate my chance of recurrence in the next ten years to be less than 2%.

My treatment was done with the Varian TruBeam machine. It was done with an endorectal balloon rather than a gel spacer. I drove 2.5 hours each way to Cleveland for treatment and experienced no fatigue whatsoever and actually attended spinning classes at our YMCA most evenings. Following the third fraction I had some mild burning when urinating that cleared on its own. Also, I experienced the same mild burning with ejaculation (mostly dry); but, sex was great even on treatment days. Three weeks post treatment I had no side effects at all and those great results continue. I was a low volume Gleason 6 that chose SBRT and early treatment and I have no regrets.

Vic, I find your post as well as the replies very interesting and informative. I also hope that the issues in front of you resolve quickly.

@Djin, I’m not certain of the radiation dose I received. I believe it was 36.25 Gy. I was shown the radiation plan on the RO’s computer and it was variable in that areas of my prostate and surrounding tissue would receive varying amounts of radiation. I did take a picture of a two dimensional slice that showed a 36.25 Gy line around the prostate. Area’s within the prostate would received more and area’s around the prostate less as indicated by the lines and varying dose. I regret not taking more pictures; especially the three dimensional views I was shown. At that point I began to realize all the efforts that go into the simulation visit and the total team effort involved. My wife and I were convinced that we were in good hands and the technology involved was pretty incredible. I also understood that SBRT even with more than ten years of experience was still evolving.

Djin, I'm wrong about cryo; it does target the tumor and not the whole gland.

In August of 2019 I had five Cyberknife treatments of 7.25 Gy each for a total of 36.25. I know that a very small margin surrounding the prostate was included in the treatment path, which factored into my choice for Cyberknife in case there was an as yet unseen micro met outside the organ. I seem to recall that the total dose of radiation was at least partially based on the amount of cancer found in my biopsy. I was a 3+4 with only 5% of one core with pattern 4 disease as verified by Johns Hopkins. The RO told me I might experience some bounce at or after the 18 month post-treatment mark. So far I've had one bounce right at the 18 month mark, perhaps from the abscopal effect of dying cancer cells expressing PSA. It was my understanding at the time that if my biopsy second opinion resulted in a higher level of disease, it might change the dosage of radiation depending on other co-treatments ie: ADT.

I've had no side effects from Cyberknife and I did have the SpaceOAR.

Vic, I applaud your efforts to get on top of this in the event that radiation didn't get all of your disease. Based on my own layman's experience it seems that your treatment plan was consistent with your level of disease as defined by your biopsy. I suppose it's possible that there was diseased tissue not extracted for biopsy, but then again your MRI indicated only a Pirads 1. For me, the positive in all this is that you haven't yet reached your Nadir. I like that you're researching your next possible treatment steps and I'll be watching your progress.

Best of luck to you.

Sr Sailor said...
Here's a link to a publication focused on the use of cryotherapy after SBRT:
https://pubmed.ncbi.nlm.nih.gov/33251131/

Interestingly (?) it's from the Georgetown University group where I was treated. The number of patients (12) that were treated with cryo is small; likely because this scenario is uncommon (fortunately). Good (short-term!) outcome for 11.
Also note that some patients were treated with focal cryo, others with total gland cryo (table 4).

SS, thanks for the link. I read the paper and did note that for some reason Brachy or HDR was not available to the study group for salvage procedures, yet HIFU was. In my research for a path forward I'm still waiting to hear from Dr. Coleman's office re: IRE/NanoKnife but due to its relative immaturity, ILF and a likely $10K to $30K out of pocket I'll probably cross that off my list. Plus it's hard to find anybody who's had this done.

Cryo is still in the running though I'm concerned with damage and SE to adjacent tissues. I'll be talking to a respected cryo doc next week I hope.

HDR seems still to be the best option and I have a telcon scheduled with Dr. Mark McChord in the Atlanta area on Friday.

It's interesting in the article to see recurrence times of 5 to 10 years whereas my ILF from Cyberknife was 18 months. The article also note that total doses of 40Gy or more produced much less failure down the road (as mentioned in this thread), I guess at the possible expense of SE. My SBRT dose was the standard 36.25Gy over 5 sessions/fractions and I've had no SE at all, just the hassle of having to deal with it at 18 mo. One thing that I've resigned myself to is that I'll likely be dealing with this for the rest of my life with recurrences and subsequent focused therapies in the future. Right now 5 years seems like a great outcome.

I'm confused as my dose was 180 of IMRT then I stopped and had SBRT at Gy of 725
And to confuse it even more, he lists the total at 3,625??

Is this a mistake? Or should I be glowing?

Glen

I recently had a discussion with my RO about the various dosages used in SBRT over the past 5 or 10 years. When I asked her about which made more sense, 36.25 Gy or 40.00, she said "Yes."

After I finished laughing, I asked her why she felt this way. She said that there are numerous platforms in use these days to deliver SBRT treatment. (e.g. Varian, AccuRay CyberKnife, etc.) While they are all versions of SBRT platforms, they are really not the same. They have different beam focal lengths, different beam shapes, different intensity capabilities, timing, etc. She indicated that for one machine, 36.25 Gy may be perfect, while another machine, for the same patient, may require 40.00 Gy. It is her opinion that the range of 36-40 Gy is right, but the decision needs to be made in conjunction with the specific capabilities of the machine in use.

She is confident that the 36.25 Gy I received was/is the optimum dosage for me, using their machine. My results, at 5 1/2 years, bear this out. (I will start another thread about my 5 1/2 year results after I have my uro appointment tomorrow. I want to include any of his observations, too.)

Paxton. Thanks for your experience. That certainly complicates the picture of adequate dosing. I know that hospitals use "dummies" of various types to measure the amount of radiation received at the skin down to internal organs on different platforms.

Djin