Ok now I am REALLY confused !!!

[Timjk]

I went to the CK Patient Support Group website. I posted my questions and then looked thru the website.. It says the number of treatments would be between 3 and 5 sessions.. My question is : why the difference in the number of treatments from CK to Novalis ??  5 sessions compared to 30 ??
The LAST thing I want is nerve damage from a possible high radiation dosage ... Does this make sense ??

Tim  timjk54@verizon.net

[Mark]

Some of the protocol difference can be related to the doctors personal preference as to what is best , however, the primary difference between the two machines is the level of accuracy. A radiosurgery machine such as CK can deliver a very high dose to the tumore with minimal collateral impact on surrounding structures. Radiotherapy machines such as Novalis aren't as accurate, so spreading the dose in much smaller increments is how it minimizes potential damage to healthy tissue.

Mark

[Timjk]

Thank you,Mark.. That makes sense to me.. The main reason we are talking about using the lower dosage therapy is to lessen the chance of nerve damage..

I feel Moffitt Cancer Center is still my best option as for a location without flying across the country.
I received wonderful treatment when I had my surgery in February.
I just want to be that confident with this procedure also..
As we all know, we aren't talking about radiating an ingrown toenail here.. We are talking about the BRAIN !!!

Tim

[Mark]

Tim,

just to clarify the radiation dose issue from my initial post. The smaller daily dose by a machine like Novalis when it is spread out over 30 days will result in a much larger cumulative dose. For example

one dose GK or CK is about 12 GY

3 fraction CK is 18 GY

30 fraction Novalis will be between 40-50 GY.

What the impact is of all that I'm not sure, but generally avoiding too much radiation is preferable in my view.

Mark

[ppearl214]

Mark, as usual, you are "spot on"   I had 5 fractions at 6Gy for 30 Gy total.

Thanks for always sharing the wisdom!

Phyl

[Jim Scott]

Hi, Tim:

FWIW: I had FSR (26 treatments) and they were very carefully 'plotted' by my radiation oncologist and neurologist using MRI and CT scans as a guide.  The result was no nerve damage, no side-effects and MRI-verified tumor necrosis within 8 months.

I trust you'll have a similar experience. 

Jim

[Mark]

Tim,

I think one of the confusing things in this whole decision process is the tendency to intermix terminology at times and be too generic in assigning outcome probabilities for a treatment option based on one isloated study or piece of information. That is part of the learning process for many of us.

 For example, within surgery there are three routes and there are some variations in outcome probabilities , yet some studies lump them altogether and create "average" expectations for sugery in general. Same is true in the radiation AN world as well, but instead of surgical procedures we have radiation protocols. In surgery, part of the reason studies get blended together I believe is that surgeons at a facility may practice multiple routes so there is less focus on analyzing the differences. there are some studies of studies that have done just that in the past.  In radiation, since many facilities have only one type of machine and that can influence what clinicians feel is the most effective protocol as much as their own preferences, the studies tend to be more specific.

In my initial response to you I stated that I thought the machine type was a greater factor in the protocol choice and that the outcomes were not much different from one to the other. Afterwards, I went looking for a study in my archives to support that statement and couldn't come up with it. So, wanting to make sure I wasn't wandering "off the reservation" with my thinking, I posed the question over on the CPSG board and got an interesting response from Dr. Medbery who I put a lot of credence in his being aware of and up to date on the published literature. The answer focused strictly on whether there was any outcome differences between radiosurgery ( 1 dose (GK) or 3-5 fractions ( typically CK) protocols) and FSR which is the 25-30 treatment plans. While there are always discussions back and forth about the merits and capabilities of different machines in this forum, I don't think I've seen much concerning any variations in protocol results.

So FWIW, here is Dr. Medbery's response to the question I posed

Don't know if it clears anything up for you but hopefully it's some useful information

Mark

I think any objective review of the FSR data would suggest the following:
1. THe best control rates reported with FSR are at the lower end of what we would expect with radiosurgery, and sometimes considerably lower than we would expect.
2. Hearing preservation has been variable, but there is at least no evidence that there is better hearing preservation with FSR, and it may be worse.
3. Complications may be a little higher with FSR, although I would not want to defend that statement too vigorously. At the very least, there is no evidence that FSR reduces complications.

We continue to recommend radiosurgery in this situation, preferably in 3-5 fractions on the CK but with GK being a pretty good alternative if more available.


--------------------------------------------------------------------------------
Clinton A. Medbery, III, M.D.
St. Anthony Hospital Cyberknife Center
(405) 272-7311
buddy@swrads.org

[sgerrard]

Taking another approach, the unit of measure for absorbed radiation in use here is the Gy (gray). Looking it up on Wikipedia reveals that "A whole-body dose of 10-20 grays of high-energy radiation, delivered at one time, can be fatal to humans." Note that is whole body, not one spot.

They used to use a dose of 25 Gy for Gammaknife, and dialed it down to 12-13 Gy about 10 years ago. Maybe not low enough, though. My notion is that getting the daily dose below 10 Gy avoids the "blast" effect of radiation, where tissue is actually directly killed by absorbing too much energy. Below that level, the effect is mainly "biological", that is, creating free radicals that cause damage to DNA. Cells with damaged DNA that try to grow will sputter and die because they can't divide properly anymore.

So, CK has the benefit of allowing a small enough dose to be primarily biological, coming in at 6-7 Gy per day, for 3-5 days. FSR goes even lower, to 2 Gy or so, but then repeats that dose 25-30 times. Based on the comment above from Dr. Medbery, and others, you might conclude that whatever benefit you gain by going down to 2 Gy per day, you lose by repeating the dose 5-10 times as often. Lots of smaller doses means more chances for "off target" radiation, and the indication is that 6-7 Gy is "small enough" to avoid the blast effect and to minimize collateral damage.

That's my story, anyway, and I'm sticking to it.   

There are plenty of success stories with all three types of radiation treatment, and as you can tell, Jim is obviously pleased with his FSR treatment. My impression is similar to what Dr. Medbery said, that CK seems to have the lowest frequency of negative results, but they are all reasonable choices. In the end, you just pick a horse and go for a ride.

Steve

[Dealy]

I thought I would interject my 2 cents worth based on only my opinion. Mark-Jim and Steve have very valid points concerning CK versus FSR. We have seen success from both protocols and failures from both methods. However-I feel the proof is in the so called pudding- Some of us are dealing with a condition called NF2 which is a total different animal (No better name for it) than sporadic AN's. I have seen success with FSR for NF2 but none for CK. Does that mean CK will not work for NF2-NO-I just have seen no evidence in studies regarding NF2. I am not pushing FSR over CK or even GK. I chose my horse-FSR and I am going to have to live with that decision good or bad-and yes I did have nerve damage from the radiation to the Trigeminial Nerve. Tim-this is a life altering decision-not easy- I may have chosen CK because Oklahoma City is 6 hours from where I live compared to Baltimore, Maryland. We made my year and a half appoinment tentative for the 27th of December-if I pass this test-it will be just another milestone to say-well we made it this far w/o major complications except my nerve damage which is being controlled by Neurontin. Tim-hope you can make a decision based on what you feel is best for you and go for it. The Cable Guy on TV has a saying-it is Git Her Done. Thanks Ron. Note-The Comedian known as the Cable Guy.

[jemcmac]

I say forget about 3 or 30 session treatment.  WHat about Gamma Knife? Have you considered it.  Dose delivery is accomplished in a SINGLE session, highly focused, high-precision in accuracy in targeting tumor up to 0.3mm (Cyberknife is 1mm) and has 201 rays where each individual beam is weak and will not cause any effects in the healthy tissue but when 201 of them converge to the tumor it is a high dose radiation where it should destroy the tumor. By far this is the gold standard treatment for small intracranial tumor.

[pearchica]

I opted for CK as it was less invasive than gamma knife. GK requires a head frame.  Having said that, we have lots of GK'ers on the website- they give you a nice happy pill prior to the head frame being attached to your head so if you feel that one session is what you want- then you  should go with CK.


If you can live with lying on a table with a plastic mesh mask over your face for 30-45 minute intervals- 3 to 5 days in succession- then you should opt for CK.

I was very please with my CK experience at Stanford. For me it seemed more comfortable than a head frame.  Hope this helps or alleviate's confusion.  Take care, Annie