SBRT to surgical bed and WPRT (Excalibur Trial) vs IMRT

[jjpeabody]

My long journey deciding on a treatment for BCR to surgical bed as noted on PSMA PET/CT and MRI 3/2021 with no metastasis noted has lead me to the decision for SRT, either SBRT or IMRT. I've been on Eligard since 3/2021 and PSA 0.1< and testosterone 21ng. I have consulted Mayo AZ (surgical bed only); Dr. Howard Sandler per Tall_Allen (IMRT surgical bed plus WPRT); Dr. Mark Scholz (SBRT with WPRT); and Dr. Amar Kishan whom I am in communication with regarding EXCALIBUR TRIAL which is all SBRT. Dr. Sandler provided a couple referrals to Dr's Terrence Roberts and Rachit Kumar for Phoenix area MD Anderson (probably IMRT) and I will meet with Dr. Roberts on 10/8. The EXCALIBUR TRIAL will be MRI-guidence and repositioning in real time, I am assuming. I asked with that technology how can there be any comparison between IMRT and SBRT. QOL of life is very important to me and SBRT for SRT including WPRT does worry me. I liked Dr. Sandler, Dr. Scholz said he was world renowned, it would cost about $7K for lodging and 2 months from my house. Dr. Kishan was very good, the recruiting for trial seems a little aggressive to me, but they seem pretty confident in my treatment. Waiting on Decipher test and another test to inform about my reaction to radiation toxicity. Any thoughts or experiences in this regard between SBRT and IMRT and including WPRT is of course greatly appreciated. Thank you, Jim

[tango65]

Good plan. Whatever the technique the most important thing is that they treat with the adequate dose of radiation whatever lesions they know exist and the ones they can not see.

Wishing you the best of luck.!!

[Tall_Allen]

You can't do better than Sandler or Kishan. I think MRIdian will prove to have an advantage for SRT especially with WPRT because Kishan contours the rectum and bowels. That kind of precision is necessary with the very high SBRT treatments. But IMRT is at much lower doses per treatment, so some beam misses here and there do not matter very much, and VMAT is excellent. Also, MRIdian takes much longer per treatment - that can be an issue when you are trying to remain still with a full bladder.

[jjpeabody in reply to Tall_Allen]

Thank you Tall_Allen, and especially for Dr. Sandler. I have a follow-up appointment with him to discuss the SBRT treatment and an appointment I have with a doctor ⁹a trusted friend of his recommended in Phoenix where I live. After I talk with Dr. Sandler again I should be ready to make the decision. I have some concerns re SBRT primarily based on my lack of knowledge. The idea of "convenience" is not something that would influence my decision. I am more concerned about toxicity issues, especially long term but S/T also as I will be driving to LA from Phoenix. Are we expecting SBRT to essentially cover the same treatment field in surgical bed and whole pelvic lymph nodes as IMRT but basically using a higher dose per treatment? I guess the toxicity issue is what the trial is about, so it would appear IMRT outcomes are generally well known and seems "safer" because we already have this data. Dr Kishan appears confident for my situation and less concerned about toxicity but more about how ADT may have made the tumor not visible with MRI, we do have an MRI from 3/2021 that shows tumor. Many people have commented positively re SBRT for primary prostate cancer/tumors and certain metastatic tumors but I don't know about high risk SRT as in this trial. With Dr Kishan's reputation and Dr Scholz's blessing, it's tilting toward SBRT. Jim

[Tall_Allen in reply to jjpeabody]

The relative toxicity of SBRT has been the subject of two randomized clinical trials. The one in Scandinavia was not done on a platform that would be currently used for SBRT, yet patients did not notice any difference in side effects:

prostatecancer.news/2016/09...

More recently, the PACE B randomized trial in the UK showed that there was no difference in acute toxicity or in acute patient-reported outcomes:

ncbi.nlm.nih.gov/pmc/articl...

PACE B just reported late-term outcomes at a conference (ESTRO 2021). They found no significant differences as long as appropriate linacs were used.

PACE C will look at randomized high risk patients specifically, but there are no results yet.

I think whole-pelvic treatment for high risk has excellent oncological results, whether or not SBRT is used.

prostatecancer.news/2021/08...

Be sure to bring a urinal in the car with you if you are driving back to Phoenix after treatment.

[jjpeabody in reply to Tall_Allen]

Thanks for these results, I was just getting ready to continue looking on the internet, this really helps. Dr Kishan said I would likely wait a couple days before trip back due to some rectal bleeding, I'll be sure to ask about urinary issues and preparations also. Thanks again, you have been a great help, Jim

[Schwah]

I can tell you two things. Dr. Kishan is awesome. He’s done SBRT on my mets. He’s kind and smart and patient with all your questions. Dr Scholz is my Doctor and I would likely go with his recommendation.

Schwah

[podsart]

I must have missed something but did you say you are doing these treatments with seems like an undetectable PSA?

If so, how are these scans able to find anything?

[jjpeabody in reply to podsart]

Hi podsart, I think especially for high risk recurrent PCa ADT is used with SRT frequently resulting in an undetectable PSA before SRT, and just like WPRT where the pelvic lymph nodes may be radiated without evidence of metastasis. At this point as noted in previous posts I am still in talks re SBRT or IMRT. Thanks, Jim

[podsart in reply to jjpeabody]

Interesting, confused as how they know exactly where to aim the radiation with an undetectable PSA , which I thought meant none of the scans can see and therefore locate the Pca. Sorry for all these questions.