I have seen 2 different radiation oncologists (ROs) in the Seattle area, and both have told me that the only option for pelvic radiation is IMRT, not SBRT.
One said it had to do with the toxicity to adjacent organs and the other that there haven't been phase 3 trials on the efficacy / toxicity of SBRT for whole pelvic radiation (vs IMRT).
Then I saw a medical oncologist (MO) who threw cold water on all that and said SBRT was definitely an option for whole pelvic radiation therapy. He threw shade on those ROs saying they are basically protecting their bottom line.
Has anyone here done SBRT for whole pelvis radiation? Or does anyone have any comments to shed light on these different viewpoints?
All things being equal it seems like SBRT would be preferred for practical reasons, but all things may not be equal.
Thanks.
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When considering whole pelvic radiation for prostate cancer, both Intensity-Modulated Radiation Therapy (IMRT) and Stereotactic Body Radiation Therapy (SBRT) are viable treatment options. However, the choice between the two depends on several factors, including the patient's specific clinical situation and treatment goals. Here are some key points to consider:
1. IMRT (Intensity-Modulated Radiation Therapy):
- IMRT is a widely used technique that delivers radiation to the prostate and surrounding pelvic lymph nodes using multiple beams with varying intensities.
- It allows for precise dose delivery, minimizing radiation exposure to nearby healthy tissues and organs.
- IMRT is typically delivered over a course of 7-8 weeks, with daily treatments (Monday-Friday).
- The total radiation dose is typically around 70 Gy (Gray), divided into smaller fractions (e.g., 1.8-2 Gy per fraction).
2. SBRT (Stereotactic Body Radiation Therapy):
- SBRT is a newer technique that delivers highly focused, high-dose radiation to the prostate and pelvic lymph nodes in a few treatment sessions.
- It uses advanced imaging and precise targeting to deliver radiation with extreme accuracy.
- SBRT is typically delivered over a shorter period, with 5 treatments given every other day or once a week.
- The total radiation dose is typically around 35-40 Gy, delivered in larger fractions (e.g., 7-8 Gy per fraction).
Factors to consider when choosing between IMRT and SBRT:
- Tumor characteristics: SBRT may be more suitable for low-risk or intermediate-risk prostate cancer, while IMRT is often preferred for high-risk disease.
- Patient factors: SBRT may be more convenient for patients who prefer a shorter treatment course, as it requires fewer treatment sessions.
- Normal tissue tolerance: IMRT may be preferred in cases where there are concerns about nearby organs at risk, such as the bladder or rectum.
Ultimately, the decision between IMRT and SBRT should be made on an individual basis, considering the patient's specific clinical situation and preferences. It is important to consult with a radiation oncologist who can assess the patient's case and provide personalized treatment recommendations.
Reference:
National Comprehensive Cancer Network (NCCN). Prostate Cancer. Version 2.2021.
The answer to your question „who knows more“ is tricky. In this forum e.g. are people with more knowledge than many MO and RO. I think the response from the medical AI provides a good base for a discussion with a trusted doctor. If I get it right, the individual placement of the organs seems to be important.
I went through this therapy and for my RO it was clear, that I got IMRT/VMAT.
I hear you about an MO expressing a strong opinion overriding a RO. This MO in particular is well regarded but does seem to have a bit of a rebellious streak when it comes to the advice of ROs and uros.
While what you say may be true, I believe SBRT also is used to target metastases that can be seen on a scan. But I'm referring to something different which is when a patient opts for whole pelvis radiotherapy for whatever reason (salvage or adjuvant treatment), but does not have a target.
I thought both SBRT and IMRT were very targeted, the primary differences being in the dosage per session and number of sessions. So I find it confusing when it says "IMRT may be preferred in cases where there are concerns about nearby organs at risk, such as the bladder or rectum". IMRT delivers more radiation actually...so is there proof that normal tissues do better with more radiation at lower doses vs less radiation at higher doses?
I was planned to get SBRT WPRT, my RO was proceeding with that plan until the therapy physicist shut it down due to organ proximity. My RO said it was a testament to my fitness that I had no visceral fat but it made SBRT unworkable. So I ended up with just prostate and SV SBRT. No PLN treatment thus far.
It is experimental. You can only get it via a clinical trial. I know Dr. Kishan does it on his high-risk SBRT clinical trial using 25 Gy within 5 treatments to the pelvic LNs (the prostate gets 40 Gy in the same 5 treatments for those who have not had RP). Most others deliver 45-50 Gy across 25 treatments to the pelvic LN area, as in Lin or Murthy in the link below.
A lot depends on your individual anatomy. This is one time where fat is better! I felt more comfortable about SBRT to pelvic LNs when Viewray was in business.
I had 2 separate rounds of SBRT. First in April 2023 for prostate and lymph nodes. Second in late November 2023 for bone mets in pelvic area, femur and spine. Both rounds through Dr. Spratt at University Hospitals in Cleveland. Might be worth contacting his office. My first undetectable PSA was in April 2023, just prior to SBRT. Still <0.04 in December. Next test in a few weeks.
Why not ViewRay/MRIdian? Is this no longer an option... MRI Guided Radiation delivery with pause when any bodily movement detected seems superior to me... Especially from experience where I sat on the table for 40x 1.8gy (72gy total) over 8 weeks of treatment. I can tell you while under the Water Protocol receiving such therapy, there were times I was moving for such trying to hold my bladder while on the table! Not often, but definitely happened once or twice!
Read the comment and well aware of ViewRay efficacy as I almost used it last year. Instead had SBRT applied in "Whack-a-Mole" therapy for some suspicious spots barely revealed during PSMA testing for recurrence when Orgovyx failed post Chemo... anyways...
I believe the 'tracking' mechanism employing the MRI would provide superior mitigation for radiation toxicity vs normal delivery. Interestingly the SBRT is still the same, same margins I'm delivery, etc. So patient specific benefit consideration of course, as noted.
The company and brand may be by the wayside, but the question is, have institutions seized the technology and continued its use? I know MSKCC had their own (forget the name) MRI SBRT as an example. So who knows... I haven't looked into it as my therapy seems to have had it's intended result, with the addition of some drugs lol...
Again, just wondering if the Rose is still a Rose, by any other name...
Currently in the middle of IMRT myself, today will be treatment 23 which is the end of the first broad radiation phase, then will start to narrow what they call 11 then 6 on my way to 40 treatments,
I have my main RO and a covering RO for weekly check up discussions, I asked them about SBRT and they both said there is a possibility of very serious side effects with SBRT but only a 5% chance, they feel best not to take that chance.
Fewer treatments is tempting because this is not pleasant, full bladder empty colon, scheduling etc. Excluding possible side effects, does SBRT provide an equal outcome to IMRT?
Not sure if you asked your RO because you saw this thread or not, but glad all the same.
I think the goal is always finding the maximal but safe dosage of radiation, so in that respect, I think SBRT may be preferred but of course, comes with risk.
You said: "... told me that the only option for pelvic radiation is IMRT, not SBRT... said that there haven't been phase 3 trials on the efficacy / toxicity of SBRT for whole pelvic radiation (vs IMRT)... Then I saw a medical oncologist (MO) who... said SBRT was definitely an option for whole pelvic radiation therapy... Has anyone here done SBRT for whole pelvis radiation? Or does any.one have any comments to shed light on these different viewpoints?"
I had one pelvic node to radiate, which would have been done with SBRT. But I wanted to do that node plus the whole pelvis prophylactically to discourage undetected cells. I was told that only IMRT could do all that simultaneously, and that's what I did.
I think SBRT is focal and cannot do several targets at once, nor can SBRT radiate one node intensely while lightly radiating the whole pelvis.
Dads RO in 2021 due to one met that became active wanted to do SBRT, he put the insurance auth in and it got denied, they said since he had multiple pelvic meds he had to do whole pelvic radiation and they would only cover one large dose, they appealed it stating that only one was active and they denied it again saying one whole pelvic high dose so that is what he had, it did knock that one out and no others up til now have become active. My brother had 45 treatments to his prostate at diagnosis, I believe it was IMRT.
Just returned from my 6 month follow up with my RO. I asked her what dosage I had to the prostrate, 70 GY and 44 GY to the whole Pelvic area. It was IMRT over 25 sessions. I am doing great after this.
She explained doing the pelvic area in the hopes of stopping microscopic cancer is a somewhat debatable topic. Some say yes. Some say no. Where she was trained they found it to be a very effective method.
In my mind I was happy to try and get ahead of the cancer and get it all done at once. She mentioned that the radiation effects the cancer cells and does not really impact normal sells in the long term.
Hope that helps. No discussion of doing SBRT. Honestly this is a regional hospital and may not have the equipment but I did not go into that. I was happy to do 25 versus 45 treatments. I believe she did the best thing for me.
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lol...
Chemo+ radiation+combo hormone therapy
SBRT Failure , offically
Radiation Therapy 
Seeking Input on Salvage Radiation Therapy
