Gamma Knife or Cyber Knife?

[Derek]

During my recent annual consultation with my neurosurgeon (in whom I have complete trust and who specialises in my prefered GK future treatment option) I mentioned that the Cyber Knife process was being introduced elsewhere in the UK in the near future and asked whether his organisation was considering eventually acquiring that system in preference to the Gamma Knife.

His unbiased response was that it was indeed intended to acquire Cyber Knife but that it would only be used for treatments to other parts of the body which could not be undertaken via the Gamma Knife and that he would NEVER use it for skull based radiosurgery such as the treatment of acoustic neuromas. His rationale was that whilst accepting that the rigid and fixed head frame used in the Gamma Knife procedure was perceived as somewhat inconvenient and uncomfortable when compared to the Cyber Knife, it nevertheless ensured 100% no risk of movement during the delicate radiosurgery operation in preference to the reliance on the Cyber Knife computer software to automatically adjust the equipment should any inadvertent moving of the head occur during the radiation procedure. In essence he was implying that however remote the risk may be of a malfunction occuring in the software, he was not personally prepared to put patients at any additional and unneccessary risk.

Whilst I have already opted for Gamma Knife treatment, if and when that becomes neccessary, I have to say that I considered his comments were worthy of note when evaluating the available stereotactic radiosurgery treatment options.

Regards

Derek

[MaryBKAriz]

hmmmmmmmm, interesting.

I am waiting to see the specialist here that does both CK and GK (the new Perfexion model). I vacillate between the 2 and am trying to learn the pros and cons of each. I am sure it would also depend on hearing and facial nerve.

Thank you for the input....any others out there?

Mary

[ppearl214]

Hi Derek and thanks for sharing that. I'm rather intriqued by the dr's rationale..... I know you participate on the CK Patient support board... I'd be cuirous of Medbery and Spunberg's thoughts on your dr's reasoning for not to use CK on skull based tumors.  Possibly toss it at them to get their thoughts on it..... I'm  withholding mine on it.

Phyl

[MaryBKAriz]

Thanks Phyl for the idea. Derek, if you find out what those docs say, would you share it?

Thanks,

Mary

BTW...heading for a ANA support meeting today in Phoenix. That should be interesting.  Take care!

[Derek]

Mary / Phyl...

During my consultation I also asked the neuro' whether his organisation were considering acquiring the GK 'Perfexion' model. His response was that they would probably eventuallly opt for that model as a replacement of their current 'Model C' equipment particularly as the newer model was also suitable for radiosurgery of the spinal area. He did not believe that there was any distinct advantage of the 'Model C' v 'Perfexion' re the treatment of acoustic neuromas that would warrant immediate replacement.

I will endeavour to obtain a response from the doctors on the CKPSG board re the aspects relevant to my neuro' and his personal reasoning for not using CK on skull based tumours. I will post their response here albeit I am confident that Drs Medbery and Spunberg will have a counter argument fully supporting the use of CK!

Regards

Derek

[Mark]

Derek,

as you noted, I know you post on the CPSG board and I'll be anxious to see how Medbery / Spunberg et al respond to the assertions of your neurosurgeon. However, I suspect it will go along the following lines

1) while I respect the fact you have a lot of confidence in your neurosurgeon, I would also say that while they may be "unbiased" they are also quite "uniformed" about how CK is designed to work. The comments are inaccurate on several levels. GK and CK both rely on software in programming their targeting. GK requires the headframe because it has no ability to verify position during treatment. CK verifys head / AN placement through active monitoring during the treatment process. If you move from where it thinks you should be it stops treatment. Hopefully your neurosurgeon will read the manual when the CK arrives since he/she doesn't apparently understand how it operates.

2) the GK perfexion version is irrelevant to the AN application discussion. It is Elektra's attempt to expand GK beyond a pure cranial application but falls far short of CK's ability/ flexibilty to treat tumors throughout the entire body.

Mark

[sgerrard]

Hi Derek,

Curious. I had more or less the same information, and came to exactly the opposite conclusion. I very much liked the fact that the CK machine was capable of real time imaging, guiding the beam into position based on where my head actually was. It is like a guided missile, rather than a ballistic missile. I find it odd that would be interpreted as an additional risk, not an improvement.

I am a computer programmer, so I guess I have a tendency to like electronically controlled systems, robotics, and high tech solutions. None of the clinic evidence I have seen suggests to me that there is any problem with the targeting in CK.

Steve

[Derek]

Hi all...

As requested I posted the relevant query to the doctors on the CKPSG board and Dr Medbery has provided  the following verbatim response:

(quote) "He is correct. He is not fully confident but most of us are. We have a number of lines of evidence to prove we are right. We have compared results in patients treated on GK with those treated on CK (so we have both available) and they are identical. We have regular testing to show that targeting is correct. Also, a dirty secret is that patients treated with the GK are not rigidly immobilised. They can tilt their heads several degrees and that motion is not accounted for by the GK. GK'ers just assume it is not important. Software controls many things and the CK is not the only place where you put your life in the hands of a computer program." (unquote)

In noting that response and the comments of Mark and Steve it is worthy of mention that all three are understandibly proponents of the CK procedure re Dr Medbery being affiliated to CyberKnife and Mark and Steve having undergone CK treatment. The majority of posts on this forum in the ongoing CK v GK debate tend to  suggest that the main reason why those who opt for CK over GK is down to the simple fact that CK does not require the fitting of a rigid head frame bolted to the skull.

In fairness to my neurosurgeon, who is an eminent and renowned professional and  who has produced many research papers on the treatment of cranial based tumours and associated medical problems, his comments relevant to CK are his personal perceptions based upon his research. I am aware that his organisation replaced their previous GK equipment with the GK Model C in recent years and I feel certain that due consideration would have been given to installing the alternative CK at that time including full perusal of the 'manual'!. If my neuro's concerns are solely attributable to a perceived risk to his patients' welfare, however minimal that may be, then I think he is to be applauded for his stance which can only increase patients' confidence that they are in caring and capable hands at such a crucial decision making time.

From a personal perspective I would still opt for the GK procedure involving the rigid head frame and the static radiation process over the face mask and moving robotic arm procedure associated with CK.

The bottom line with this debate is the fundamerntal aspect that it is incumbent upon the individual to undertake maximum research and ultimately select a neurosurgeon in whom they have complete trust and a treatment option of their own choosing which they are comfortable with and which they are totally confident about.

Regards

Derek

[ppearl214]

In noting that response and the comments of Mark and Steve it is worthy of mention that all three are understandibly proponents of the CK procedure re Dr Medbery being affiliated to CyberKnife and Mark and Steve having undergone CK treatment.

Hey Derek,

to elaborate on this comment, please know that Dr. Medbery is a good source for this question as he performs, both, GK and CK..... he has publically posted that they do more CK now than GK, but he has also been doing GK at his center for many years, so, to me, he can provide the best answer having performed both on a continual basis.... this is only FYI.

Phyl

[Derek]

Hi Phyl...

I was aware that Dr Medbery specialised in GK and CK but there is little doubt that he favours the CK procedure. I read in a thread in the 'Brain' forum on the CKPSG board posted on 11 April under the heading 'Dr Medbery / Why do you prefer CK over GK' whereby the poster queried whether Dr Medbery had an 'in' with CyberKnife and the doctor responded confirming that he had....not sure what the 'in' refered to?

In order to avoid any ambiguity, I have the utmost respect for the professional advice that is regularly provided by Dr Medbery and in no way was my relevant post in this thread intended to imply that I was dismissive of his considered response with regard to the point on CK procedure raised by my neurosurgeon. They are both eminent professionals entitled to their respective opinions and as previously stated it is incumbent upon the individual to make up their own minds with regard to eventual treatment choice.

Regards

Derek

[ppearl214]

Hey Derek,

Oh, no biggie! I knew you had some participation on the CK Patient Support board but didn't know if you had knowledge that he performs both.... again, it was FYI only in case you didn't know.....

Phyl

[MaryBKAriz]

Hi folks,

All very interesting feedback. I want to consider all perspectives.

I went to the AN support group meeting at Barrows Neurological Institute last night and one of their top neurosurgeons who preforms microsurgeries as well as GKs and CKs. This hospital is one of only 4 in US that has both CK & GK treatment options. He was saying that it is a more common now for people with tumors <3cm to get radiosurgery except in those who are on the young side - like 20 when surgery might be the better option. Since I am 59, I do not fit in that category! :DThe reason they don't tend to do it up to that size is because swelling is more of an issue at sizes above that.  He said the 2 radiosurgeries function very similarily. The statistics for CK so far show better hearing preservation, however, since the statistics are not as extensive and do not have long term results, that is still a question. Also the doses would be fractionated perhaps lowering the chances of swelling.

He said the Gamma Knife Perfexion makes the treatment faster and they can now do procedures further down the spine. Both GK and CK, from what I understand are programmed. So software is involved. The CK has the robotic administration, the other the helmut thing (my words, not his... ). The robot and software is able to adjust for any minor moving such as breathing. The mask is VERY snug having been fitted to the individual's face so moving is quite restricted. The GK head frame keeps the head rigid and is attached to the skull.

He also said with CK if you live here, you come in ahead for all the preliminary work, doctor, and mask fitting. You go home and the doctors do the treatment plan before your next visit.  Then you come in 3 days in a row for treatment, about an hour (give or take for tumor size) each time.

Wth GK you come in at 5am get the preliminary stuff done the same day (because the head frame needs to be attached to do it). The doctors analyze the info while you wait with your headress, providing entertainment fo those with you (my words not his ). Then they do the procedure. It takes all morning and then you go home and you are done.

I get claustrophobia ONLY in REALLY small spaces (like an MRI) so I found out you can be medicated for that issue.

I have gotten feedback now from 3 physicians here at BNI and will have my official radiosurgery appointment with yet another physician there on May 5th when I can ask all my questions. FOR ME they all advised against surgery, but so far have not led me to one radiosurgery over another. I did talk with a leading neurosurgeon at the top hospital in India (no kidding). MY friend is from India and her brother is a top official with the hospital. I sent him my MRI and medical details. He also concurred in my case that surgery would not be a wise choice. They have both CK and GK at their hospital as well as the x-knife. He thought I should not do the watch and wait. He said almost the identical description of the guy who answered questions at the ANA meeting. He felt CK or GK were my best choices. Reading between the lines, I see a few advantages to each and a few disadvantages to each and the decision for me is fuzzy. I felt like CK in general it sounds like the reasons it might prevail is the latest and greatest (not their words - mine) in innovation BUT it hasn't been around as long as GK so the long term statistics just aren't there.

To sum up, what I think it sounds like, CK may be better technologically especially for people who have hearing to preserve. However you do not have the tried and true long term statistics of the GK so if you feel like that is a risk not worth taking, go GK, If you feel the statistics for CK have been around long enough and are showing great promise, you might want to consider it a good risk. Don't know if that makes sense but that is what I am thinking at present.

Still taking in as much info as possible about this topic,

Mary

[ppearl214]

Mary, FAB-U-LOUS post and thank you for sharing in such detail! Great job!  VERY insightful and I'm glad you had many questions answered!  I can see that you are most definately becoming the best, well-informed patient that you can be... and once you (or Derek or anyone) makes their final decision, regardless of what it is.... we're cheering you on.

thanks again!
Phyl

[sgerrard]

To sum up, what I think it sounds like, CK may be better technologically especially for people who have hearing to preserve. However you do not have the tried and true long term statistics of the GK so if you feel like that is a risk not worth taking, go GK, If you feel the statistics for CK have been around long enough and are showing great promise, you might want to consider it a good risk. Don't know if that makes sense but that is what I am thinking at present.

Hi Mary,

Like Phyl, I liked the summing up in your post. I wanted to share my view of the long term results question. It is a view shared by many patients and radiation oncologists, although not by all.

Cyberknife is a newer way of delivering focused radiation (aka radiosurgery). However, the effectiveness of focused radiation on controlling tumors is something shared by all the systems: LINAC, Trilogy, Novalis, GammaKnife, and Cyberknife included. The science of radiation treatment is all about the amount of radiation delivered precisely to the tumor, and the amount of "collateral" radiation hitting nearby tissue. If the radiation is on target, the delivery mechanism makes little difference in the results.

From that point of view, the most relevant long term results are those for focused radiation treatment in general, regardless of the machine used. In that sense, the whole body of radiosurgery results for treatment of ANs applies to all the machines, with relatively minor differences in some details between the various systems.

In my own mind, a statistic, such as one out of Pittsburgh on 15 year radiation treatment results, applies in general to radiation treatment, not just the specific machine they used. Others may view that differently, but from the radiation oncology point of view, zaps are zaps.

Steve

[MaryBKAriz]

Hi Phyl and Steve,

Thank you, Phyl. I am a trying. People on this site are great role models. It was so good to be in a meeting with many of us last night. It can feel quite lonely even with caring loved ones, because it is impossible to be in our shoes. I also got to meet Annette in person, who I met here on this web site. We were diagnosed same day, same Dr. isn't that a coincidence? !I really liked her and she is a superb person. I look forward to us cheering each other on.

Steve, GOOD point! I do remember now that the doctor said he expected the statisics will be much the same for long term results.

I never knew I could learn so much technical stuff in such a short time. The ole brain hasn't disappeared after all!

Dizzy Dame,

Mary