Experience with Image Guided IMRT

Who said that a large gland rules out SBRT? The only study I've seen on this issue was the following from Georgetown, and they found that it was "well tolerated." Also, the same machines are used to deliver SBRT and IMRT in many of the top centers, and SBRT includes extra motion trackings, so why would treating a large prostate with IMRT improve the toxicity profile? Certainly, expected toxicity is worse for large prostates, but that is true regardless of the type of radiation used. It rules out LDRBT (they sometimes shrink it with ADT first for that), but not any of the others. My prostate was 55 cc.

Stereotactic body radiation therapy (SBRT) for prostate cancer in men with large prostates (≥50 cm3)

Thanks snowboat, I appreciate your input.

TA: I hear you, but...fyi, Dr. Martinez, 1/11/17 11:30am, answer to why not SBRT
"...the bigger the gland is,the more normal tissue we are gonna treat. The more toxic the treatment gonna be in five treatments...if you have a smaller gland, we are gonna treat a smaller segment of your rectum, bladder and urethra...your best option is to give a small dose of radiation because it is gentler to your normal tissues...will you find somebody to do it (sbrt), probably you will. Will I do it, no. Because I know I'm going to hurt you..."

So, if convenience/timeliness was not a concern, would it make sense to go with 1.8 Gys over ~40 fractions, and agree with Alvaro to be gentle? Would he be unaware of the 2014 Georgetown study?

Steve,

While I think Dr Martinez really knows his stuff about HDRBT, to my knowledge, he has never treated anyone with SBRT. This goes back to what pretty much anyone on HW can tell you - go to the expert in each treatment for the treatment he does, and not for other treatments. I would no more rely on Martinez for info about SBRT than I would rely on King for info about surgery. I think Martinez is right - he would hurt you if he tried to practice SBRT on you.

He is saying two things, one is true the other is not:
(1) Toxicity of all types of radiation treatments is worse for larger glands. That's true.
(2) "a small dose of radiation because it is gentler to your normal tissues" - that is true for a single dose, but across 40 doses, that is not true. The toxicity is cumulative.

I have seen many dose-volume histograms, and the ones for SBRT show that less dose is delivered to healthy tissues by the intrafractional motion-tracking of SBRT. A typical treatment margin for SBRT is about 3 mm on the anterior side, and 0 mm on the posterior side. A typical treatment margin for IMRT is 5-10 mm. Which would you expect to be more toxic?

And the dosimetric improvement seems to carry through to patient-reported outcomes, as you can see for yourself:

/pcnrv.blogspot.com/2016/08/ldrbt-imrt-and-sbrt-quality-of-life.html

You have to talk to an SBRT doctor to learn about SBRT.

steveinErie said...
... Should a guy schedule for morning doses or afternoon? Foods to avoid (please don't say beer!), etc.

Sorry, no adult beverages . Morning or afternoon doesn't make much of a difference but it should be after you usually have a bowel movement. And having it the same time for every session is semi-important so you can get into a routine of drinking so much water at a certain of the day.

[quote] And lastly, everyone insists that the experience of the surgeon or brachytherapist is the utmost important factor when choosing your treatment, does that same importance (within reason) apply when selecting the institution for 8 weeks of radiation? (ie..can I take Dr. Martinez's radiation plan from 21st Century Oncology in Detroit and have a smaller hospital near my home employ said plan?)

(this should have been a quote block)

You want the best of the best, if you get techs that do maybe one or two a week (or a day) they might not have the skill and/or experience as a large cancer facility would. Also, your radiation oncologist should follow up with you weekly during treatment to access how you are handling radiation.

I chose to have my entire PCa mitigation managed by the staff at MD Anderson even though it's 250 miles from home. I wanted the best of the best cutting on me or nuking me - mistakes or poor performance can have disastrous results weeks or years later. During radiation we stayed in our motorhome near MDA but there are a bunch of people staying in hotels and extended stay facilities.

Definitely talk to Freeman and Katz; King too, if you want to visit LA for 10 days. I am perplexed by Kevin Stephans recommending against it. IMRT docs don't like it because it cuts into their revenues.

I shared an email with the doc at Cleveland Clinic telling him the results of my volume study and that Detroit believes that disqualifies me from HDR AND LDRBT. Here is part of his response:"...but the pubic arch anatomy you relate is not a problem for LDRBT. It is a problem for HDRBT because of the larger catheters that cannot be as easily directed around the bone in the pubic arch."

And Dr. Jeffrey Demanes (pioneer of HDRBT) reports on his website that the Pubic arch and large prostate are not problems. See Www.cetmc.com.

Believe the doctor who asks for or doesn't ask for a scan - he knows what he needs/wants to do his job. Also believe the doctor who actually practices the therapy, as I've said many times. Only he has the knowledge and experience to have an opinion worth listening to.

Does the doc who said LDRBT is a mistake practice LDRBT? Why would you believe someone who doesn't have experience with the therapy in question?

the studies show ,I believe, that IGRT, works about as well as the other treatments ....+or- .... I`m no expert like the others here , but IGRT is easy and I vote for it unless the treatment center is not nearby ....

BTW - I know your pubic arch is in the way for Martinez, but the size of your prostate should not be an issue for HDRBT. But perhaps the two combined are (that's beyond my pay grade). FWIW:

www.thegreenjournal.com/article/S0167-8140(16)34338-9/abstract

How big is your prostate?

You're both right. Volume doesn't change (compression is minimal), but the apparent volume can. The position makes a difference because the volume is an estimate based on the ellipsoid formula,

V=L x W x H x Π/6

The actual shape is more like a delicious apple than a perfect ellipse. So when the shape is distorted from the ideal ellipsoid shape (by lying on the side or the back), the calculated volume changes. US and CT are considered the gold standard, MRI not as good. But your 68 cc prostate is far from huge. A few guys in here have had prostates over 100 cc!

I'm glad you got opinions from the real experts at SBRT and didn't take someone else's word for it. How many guys would bother? I'm amazed when I meet with doctors who dispense misinformation about other therapies with such confidence that the patient believes it's established fact. I even caught a doctor I deeply respect doing that last week. I called him on it, but how many patients would?

I had to laugh at King's response. He has a thing - which I love about him - of never telling a patient which choice to make. He's all about patient empowerment, which is why we get along so well.