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25 instead of 39 IMRT treatments study -U bet I'll tell my doc tomorrow

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Posted 11/16/2009 8:24 PM (GMT 0)
I just found a reference to a study that was presented to the American Society for Radiation Oncologists (ASTRO) on November 4, 2009. It was conducted at the University of Miami School of Medicine.

http://www.redorbit.com/news/health/1779898/shorter_radiation_course_as_effective_as_standard_therapy_for_prostate/index.html

http://prostatecancerinfolink.net/2009/11/05/short-course-radiation-therapy-for-localized-prostate-cancer-two-new-trial-results/

You can bet I will discuss this when I meet my new RO at MDA tomorrow. Sure would be nice to receive 25 treatments instead of 39, especially going into the holidays. The study indicates that there was no appreciable difference in cancer recurrence after 39 months of the study.

Yee Haa!!

We'll let you know how the conversation goes,

Sonny
Posted 11/16/2009 8:34 PM (GMT 0)
Was the dose the same in both time periods? The total dose given is more important than the time period in which it is delivered.
I would be hesitant to take a lower dose even though it meant fewer treatments. If they give the same total dose in fewer treatment sessions it might be OK.
JT
Posted 11/16/2009 8:40 PM (GMT 0)
No John, the total dose was actually higher. What the study seemed to indicate was that the higher dosage could be delivered in a shorter time frame with no appreciable increase in side effects and at no detriment to the long term outcomes.

Now I realize that this study was done on guys that still had prostates, but my questions will be why wouldn't it work for Adjuvant Therapy as well.

It will be an interesting conversation I am sure.

BTW, I added another link to a similar study with a little more detail.

Sonny
Posted 11/16/2009 8:50 PM (GMT 0)
John, here is an interesting side note to SRT for me. I plugged in my numbers in the Sloan Nomograms calculator for SRT. Accurately described my situation and computed the doubling times using my two post surgery PSAs (in their calculator).

The only thing I changed was the Gy number for the treatment.

At 66Gy the Progression Free Probability at 6 years was 41%
At 70 Gy it dropped to 36%
And at 80Gy it dropped down to 21%

Now I know almost next to nothing about IMRT so far, but this just doesn't compute to me. Use more radiation and get less longevity. DUH!

What's your take on this one.

Sonny
Posted 11/16/2009 9:24 PM (GMT 0)
Sonny, I did the same thing when we thought John was heading for SRT and found that the percentages of disease-free progression dropped at the higher doses. Will be interesting to see what others have to say. The rad onc we had met with as well as our uro/surgeon had indicated a treatment of approximately 6600 rads over 7 weeks but we never got to the point where the rad onc had formulated her precise treatment plan for John.
Posted 11/16/2009 9:26 PM (GMT 0)
Sonny, I know you and I have since disucssed this, but please post what you f ind out. I believe you in what it calculated to, but it definitely contradicts what my own doctors said when determining greys for my treatment, and treatments in general.

David in SC
Posted 11/16/2009 9:41 PM (GMT 0)
P.S> There are some at my radiation clinic, that get zapped twice a day, once in the morning, once in the afternoon. It's bad enough going through this once a day, plus the logistics would be hard for a lot of people.

I agree with JohnT, you wouldn't want to short yourself on SRT now that its needed, the number zaps only matters in delivering the correct amount of greys needed to give you your best shot.

I still think 72g is a lot for salvage, but that is what my radiation oncl. calculated for my case.

David in SC
Posted 11/16/2009 10:17 PM (GMT 0)

I did this with Proton radiation at Loma Linda.  I was in a clinical study with 20 sessions instead of the standard 45.  Overall, I received less Gy (60 vs. 81) but I received a higher daily dose (3.0 Gy vs. 1.8).... This is called a hypofractionated dose.  There are studies that seem to indicate that Prostate cancer responds especially well to hypofractionated doses.  This is due to the low alpha-beta ratio of prostate cancer.  I do not claim to understand this, but my doctor at Loma Linda explained it to me in that fashion.  You can also Google "prostate cancer alpha-beta ratio" and find a bit more on the subject....but most of that is over my head.

I'm 4+ months out and my PSA has dropped from 3.0 to 1.0 and I have had no side effects at all.  Of course, the real test will come 5-10-15 years out after the survival data on these clinical trials is analyzed.

For me the hypofractionated trial saved me time away from home...it saved me money (1 month less of housing costs in Loma Linda)....in theory this should help make Proton radiation (and perhaps other radiation) more competitive from a cost standpoint.

Posted 11/16/2009 10:31 PM (GMT 0)
Of course I quickly posted my reply before reading the links in the original post... Very exciting and promising.  I do however believe that you are incorrect in saying that you will receive more total Gy if you choose the treatment with fewer doses.  And I also think that the statement above that "it's the total amount of Gy that is the most important" is also incorrect.  I bet when you check with your doctor you will find that you would get a higher daily dose, but fewer Gy if you choose the option with fewer total treatments.  Again, as my doc at LLUMC explained it to me: For prostate cancer, 60Gy is EQUAVILENT to 81 Gy when given in hypofractionated doses.  You can imagine that I asked a LOT of questions before I settled on a treatment with a smaller overall dose of radiation.  All my questions were answered to my satisfaction and I am happy that I participated in the study.


Posted 11/16/2009 10:31 PM (GMT 0)
RB thanks for the insight. Been looking at stuff like this all day to prepare for my meeting with the RO tomorrow.

I keep seeing TV's Mr. Rogers in my head saying "Can you say hypofractionated". Cracks me up every time I think about it.

Sonny
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