ANA Discussion Forum
Treatment Options => Radiation / Radiosurgery => Topic started by: mcrue on January 10, 2016, 06:37:37 am
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What are the top "pros and cons" of each?
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The following article should answer that question:
http://emedicine.medscape.com/article/857604-overview#showall
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So it's Gamma Knife if I read that article correct?
Plus, the following insert was alarming:
"while complications of radiation were significantly reduced: rates of facial nerve dysfunction and trigeminal neuralgia at a mean follow-up period of 5 years were 1.1% and 2.6%, respectively."
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Nearly all the permanant facial and trigeminal problems occurred with larger tumours. Some patients insist on getting gk even with tumors larger than 4cm these size. Over 3cm you are at much higher risk of a complication.
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So it's Gamma Knife if I read that article correct?
Only you can make that decision.
Plus, the following insert was alarming:
"while complications of radiation were significantly reduced: rates of facial nerve dysfunction and trigeminal neuralgia at a mean follow-up period of 5 years were 1.1% and 2.6%, respectively."
Didn't alarm me. I chose GK.
Here are some more articles:
http://thejns.org/doi/pdf/10.3171/2012.7.GKS12783
http://www.rportermd.com/gammacyber-knife.html
Dr Porter was my neurosurgeon.
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When my An was diagnosed at 1.8cm I was told with surgery I was looking at a 10-15% risk of facial nerve damage with surgery. When it grew to 2.4% my risk of facial paralysis grew to 25% while Gamma Knife offered only a 1-2% risk. Those statistics along with the other risks I faced with surgery, made Gamma Knife the better option for me.
Cathie
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GK Pros
slightly more accurate.
Less radiation to surrounding tissue around tumour due to faster dose fall off, theoretically less complications.
Better shielding protecting rest of body to superfluous radiation. Reducing cancer risk
Minimum beam size 4mm
GK cons.
Head frame
Not usual to fractionate, which may have an advantage in AN's but questionable.
Higher maximum radiation dose to centre of tumour creating a radiation hotspot which may be detrimental to nerves if located in the middle of the tumour.
Head frame distorts and can cause inaccuracies.
Location of tumour is not confirmed during treatment opening up the possibility for geographic misses. Misses have been confirmed as a large cause of radiation failures
More difficult to block radiation to critical structures
CK pros
No head frame more comfortable
Can be fractionated... But it's value in Acoustic Neuromas is questionable.
Tumour position is validated during treatment reducing the chance of a geographic miss from setup errors.
No hotspots reducing risk of nerve damage in a hotspot if this is a risk.
CK supports beam forming on the M6 model which is useful for larger tumours, and concave tumours
Flexibility of the robot allows more freedom to avoid critical structures
CK cons
Minimum beam size 5mm
More radiation to whole body due to less shielding very slight increase cancer risk
Slightly less accurate.. About 0.2mm for small Acoustic Neuromas (this is not considered significant as there are other errors from imaging as well)
Dose fall off is not as fast as GK especially for larger tumours.
Something people may not be aware of is the Penumbra effect.
These radiation beams are not quite the piercing straight sharp edged beam we may imagine.
The penumbra I believe is around 3mm on both CK or GK so arguing over which is more accurate maybe purely academic
I think both machines are great machines.. A good team is needed too.
The choice in my book between these two is head frame or no head frame and the team of medicos
There is also the GK model c versus the GK perfexion
There are better results for treating AN's with the perfexion
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Higher maximum radiation dose to centre of tumour creating a radiation hotspot which may be detrimental to nerves if located in the middle of the tumour.
Head frame distorts and can cause inaccuracies.
Location of tumour is not confirmed during treatment opening up the possibility for geographic misses. Misses have been confirmed as a large cause of radiation failures
More difficult to block radiation to critical structures
Something people may not be aware of is the Penumbra effect.
These radiation beams are not quite the piercing straight sharp edged beam we may imagine.
The penumbra I believe is around 3mm on both CK or GK so arguing over which is more accurate maybe purely academic
I think both machines are great machines.. A good team is needed too.
The choice in my book between these two is head frame or no head frame and the team of medicos
There is also the GK model c versus the GK perfexion
There are better results for treating AN's with the perfexion
Can an experienced team mitigate factors such as:
a) head frame distortion causing inaccuracies
b) geographic misses causing radiation failure (because tumor moves during radiation??)
c) blocking radiation to critical nerves structures (GK can't protect the facial nerve like CK treatment can??)
What is the GK success rate for small tumors less than 2cm?
98% success?
Also, have there been any "horror stories" regarding radiation treatment for AN's similar to those related to microsurgery? As I understand it, the worst "side- effect" from radiation treatment is if the tumor regrows.
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Paulw does a lot more research than I but, I've never heard of head frames being distorted and that would be a new one for me. Frankly I can't imagine the force needed to bend it. They are titanium and not fragile. I suppose there is human error involved in anything as far as geographic misses. Never heard of that either as the AN is imaged right before treatment. I would like to see statistics on those events. I assume they would be extremely rare. GK is very precise. I was told by my team that they target around the nerves. I couldn't say if that's all nerves, or just major ones. I specifically asked Dr. K. about this and he showed me the nerves from the MRI on a big monitor, where they were and that they target around them. As a side to that, facial problems are also extremely rare with GK.
CK, as noted is more radiation over several sessions. The main difference between the two are the machines of course. GK is limited to the head area whereas CK can be used for different areas of the body. It is a very good option for treating prostate cancer. Both machines have their niche but, I give GK the nod as a bit more precise.
Said many times here, whatever treatment you go with choose experience. Better results occur with more experienced teams. I was extremely blessed to have Kondziolka, Lundsford, Flickenger and others on my GK dream team.
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Can an experienced team mitigate factors such as:
None of these things can be totally mitigated but can be worked with. Its not black and white.
All of these things can be mitigated by providing more radiation to good tissue.
For instance if they zap an extra millimeter all they way around the tumour it would allow for the inaccuracies of the machine.
So its a balancing act. More Margin = More radiation= more side effects, but better tumour control.
Less Margin = less radiation, less side effects but higher risk of failure
An experienced team will totally understand the challenges and take the appropriate actions
a) head frame distortion causing inaccuracies.
Using phantoms and alignment procedures the GK Team will understand the level of inaccuracies and adjust the machine appropriately.
b) geographic misses causing radiation failure (because tumor moves during radiation??) Not for small tumours, they don't move as they are locked in the IAC
c) blocking radiation to critical nerves structures (GK can't protect the facial nerve like CK treatment can??)
Gamma Knife typically treats to the 50% Isodose line, while CK treats to 80% Isodose line.
This is configurable for both machines, but due to how they work the isodose lines differ and each is appropriate for each machine.
Disadvantage of the 50% isodose line is a higher maximum radiation dose typically 26Gy versus 16.25Gy for CK.
Mostly the nerves are to one side of the tumour, so may not matter.
The results between GK and CK are pretty much identical, Fractionated and non fractionated.
We can argue about the technical pluses and minuses but at the end of the day, it probably comes down to head frame versus no head frame, and very small increase in cancer risk to the rest of the body from CK. Any other advantages of either machine have failed to show up statistically.
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Thanks,
I agree that an experienced team equates to a higher success rate.
Dr. Lunsford at UMPC in Pittsburgh is an excellent choice for Gamma Knife, as well as Dr. Kondziolka at NYU in New York.
Dr. Chang at Stanford is an excellent choice for Cyber Knife.
They both feature experienced teams, and they perform numerous procedures annually on AN's.
There are also some excellent local teams throughout the country as well.
My "Top 10" fears from radiation treatment are probably most common:
1. Tumor regrowth
2. Hearing Loss
3. Facial paralysis
4. Mis-calculaton - zapping wrong part of brain or brain necrosis!
5. Tinnitus issues
6. Eye problems
7. Balance problems
8. Headaches - longterm
9. Trigeminal nerve problems
10. Cancer
11. Making me slow or "off"
12. Fatigue - longterm
13. Cognitive issues
14. Hemifacial spasms
15. Hydrocephalus
16. Should I expect a "new normal" after treatment?
Which one of my fears is most likely to manifest?
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How often do they perform "routine maintenance" and "recalibrate" the machine to make sure every beam is going to where it should go?
What happens if there is a power failure in the middle of the treatment?
Does Dr. Lunsford have the latest upgraded machine available or is "older" technology?
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I just had GK after leaning towards CK. I changed my mind because there is suspicion that my tumor involved the facial nerve, although it is still not known for certain. The reason I changed is that GK has been around much longer and has an extensive track record of success, which can be found by reading reviews of large clinical studies in the literature. In fact, I was surprised by comparison, how few studies have been published for CK. In my case, I viewed it as I needed radiation to absolutely work, because facial nerve surgery is catastrophic. If I knew for sure that there was no facial nerve involvement, I would have leaned toward CK.
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Radiation is most effective on small tumours. Just remember that the total amount of radiation that you need is related to the volume of the tumour. The bigger the tumour the more radiation you will need and the higher risk of complications.
At 10x5x5mm my tumour was all in the IAC and did not even touch the side of my brain. There was a 3mm gap. The volume of my tumour was 0.125cm3. A 3cm tumour has a volume of 10.6cm3
That's 85 times bigger than my tumour by volume and will need 85 times more radiation to treat it.
I was very comfortable getting radiation for my baby tumour.
As your tumour is growing aggressively it's pretty obvious that w&w is no longer a suitable management strategy. Which leaves the other two options surgery or radiation. The potential side effects of radiation won't get any better with a bigger tumour. If you are considering radiation I would seriously consider it sooner rather than later, because if your tumour keeps growing at the rate it has you will lose that option in just over 12 months. Choose an experienced team and they will do all that needs to be done. The neurosurgeons and radiation oncologists that operate these machines are geniuses. Dr Chang, Lundsford, Kondziolka are the geniuses genius.. These guys are way smarter than you and I will ever be, and some times you just need to trust them. I think right now you need to weigh up surgery versus radiation. Forget which machine, and choose the team you are most comfortable with.
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We have all heard about the 3cm limit for radiation which is about 10.5cm3
Check out this paper... Got zapped with Cyberknife for a tumour the size of a quart of milk and only had a mild reaction.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4689568/
Makes my tumour which is nearly 1000 times smaller by volume look pretty pathetic
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Radiation is most effective on small tumours. Just remember that the total amount of radiation that you need is related to the volume of the tumour. The bigger the tumour the more radiation you will need and the higher risk of complications.
At 10x5x5mm my tumour was all in the IAC and did not even touch the side of my brain. There was a 3mm gap. The volume of my tumour was 0.125cm3. A 3cm tumour has a volume of 10.6cm3
That's 85 times bigger than my tumour by volume and will need 85 times more radiation to treat it.
I was very comfortable getting radiation for my baby tumour.
As your tumour is growing aggressively it's pretty obvious that w&w is no longer a suitable management strategy. Which leaves the other two options surgery or radiation. The potential side effects of radiation won't get any better with a bigger tumour. If you are considering radiation I would seriously consider it sooner rather than later, because if your tumour keeps growing at the rate it has you will lose that option in just over 12 months. Choose an experienced team and they will do all that needs to be done. The neurosurgeons and radiation oncologists that operate these machines are geniuses. Dr Chang, Lundsford, Kondziolka are the geniuses genius.. These guys are way smarter than you and I will ever be, and some times you just need to trust them. I think right now you need to weigh up surgery versus radiation. Forget which machine, and choose the team you are most comfortable with.
Thank you PaulW. At this point, one of my main concerns is whether-or-not I will even fit into the MRI, CT, and GK machines. I'm roughly 6'5 inches tall, size 16 shoes, 375lbs, with huge "pregnant" beer belly. Does a "large" face affect the accuracy of the mask they drill into your skull?
I'd rather squeeze into a traditional MRI machine if it truly makes a difference and provides better imaging for the doctors compared to an OPEN MRI. With my "Big & Tall" size, I may hot have that option.
One neurosurgeon mentioned my AN was "bulky." Does this mean it's dense, or is it just the opposite? As you mentioned, hopefully they will know how to mitigate my fast-growing "aggressive" AN.
Do they show you the imaging of your tumor prior to your radiation treatment? I trust that's how you knew the exact size and volume and density? Will they know exactly how close the AN is in regards to surrounding facial nerves , etc?
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I don't think you will have any issues getting into the latest CT scanners
Hopefully A big new fancy MRI Should be able to squeeze you in the new Siemens machine copes with 475lb and has a 74" circumference..
The newer GK perfexion and Cyberknife robocouch have a 475lb and 500lb limit. Older machines are a problem.
The frame should not be an issue, they don't drill. The pins are pushed through the skin until they touch the skull and hold the skull in place.
If you ask to see the imaging I am sure they will show you.
Unfortunately AN's always touch the facial nerve, which means the facial nerve will always get close to the full prescribed dose of radiation. The magic of radiation is that this dose should not harm good tissue but will damage the tumour cells. Some things like the cochlear however are radio sensitive and are within 2-3 mm of many AN's. Radiation to the cochlear is thought to be a cause of many side effects and not damage to the brain itself
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My "Top 10" fears from radiation treatment are probably most common:
1. Tumor regrowth
2. Hearing Loss
3. Facial paralysis
4. Mis-calculaton - zapping wrong part of brain or brain necrosis!
5. Tinnitus issues
6. Eye problems
7. Balance problems
8. Headaches - longterm
9. Trigeminal nerve problems
10. Cancer
11. Making me slow or "off"
12. Fatigue - longterm
13. Cognitive issues
14. Hemifacial spasms
15. Hydrocephalus
16. Should I expect a "new normal" after treatment?
Which one of my fears is most likely to manifest?
Based only on my own experience with GK (3d Anniversary is tomorrow 1/22):
1. Tumor regrowth - Mine is stable - A little early for shrinkage - Next MRI Sept 2016.
2. Hearing Loss - Hearing already gone before GK.
3. Facial paralysis - Didn't happen.
4. Miscalculaton - zapping wrong part of brain or brain necrosis! - Didn't happen.
5. Tinnitus issues - Had it before GK - Still have it - Very mild - Easily ignored.
6. Eye problems - Dry eyes before GK - Still have it at night - Use drops.
7. Balance problems - Had them before GK - Resolved within a year after GK.
8. Headaches - longterm - Didn't happen.
9. Trigeminal nerve problems - Didn't happen.
10. Cancer - Hasn't happened yet. Hope it won't. At my age (69) I more concerned about my prostate. :-)
11. Making me slow or "off" - Didn't happen.
12. Fatigue - longterm - Didn't happen.
13. Cognitive issues - Didn't happen.
14. Hemifacial spasms - Didn't happen.
15. Hydrocephalus - Didn't happen.
My new normal - hearing aids. Other than, much the same as before.
Your mileage may vary.
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My Experience at 5.5 Years Post CK
1. Tumor regrowth - Stable
2. Hearing Loss - Got Better after CK then worse then better then worse. Pretty Stable now mild hearing loss in Higher frequencies Only
3. Facial paralysis - Nope
4. Mis-calculaton - zapping wrong part of brain or brain necrosis! - Radiation dose for AN's is too low for Brain Necrosis a good team doesn't get it wrong, with CK or GK
5. Tinnitus issues - nope
6. Eye problems - nope
7. Balance problems - resolved after 2 Years, annoying for 6 months. Balance not quite what it was but not noticeable, can climb rooves just fine, I go snow skiing, cycling, no issues at all.
8. Headaches - longterm - none
9. Trigeminal nerve problems -none
10. Cancer - not so far
11. Making me slow or "off" - resolved after 2 years
12. Fatigue - longterm - No Short Term mostly first 6 months
13. Cognitive issues - No - But balance issues in first 6 months did cause short term memory loss and some speech and writing issues, People that are in Watch and Wait and post surgery also describe these problems
14. Hemifacial spasms -No
15. Hydrocephalus - No
16. Should I expect a "new normal" after treatment?
Yes and no, for me I don't think my AN has affected me physically...Mentally yes I have changed, not in a cognitive way. You just look at life in a different more positive way. I value Material things less, Friends and family more, and idiots in the world that I have to deal with don't upset me anymore. I have come to realize that you are on this planet for a short time, for me I am 52 so hopefully I will hang around for quite a bit longer yet. I enjoy life more now, and my AN has taught me that. Many people have commented on how I deal with negative or difficult situations. It is a skill that I have learned because of my AN. Its all a life experience.
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Thank you for taking the time to answer each and every fear that I listed! I just can't seem to shake the idea that I will be "less conscientious" and "less sharp" after radiation.
Anyhow, reading through older posts another user recommended I ask the following of my surgeon:
Radiation
1. What is your mortality rate?
2. What is the % of the AN still growing (not killed) following your treatment?
3. What is the % of facial paralysis following your treatment?
4. How old is your equipment?
5. Whan was the software last updated?
6. What is the skill and experience level of your technicians? - this is a vital question and watch his body language when he responds. At the end of the day if the technicians are no good - forget it.
It is vital you do *NOT* get industry averages or percentages - ask for your doctor's specific numbers.
I take it they make you wear a gown during treatment (as opposed to wearing your own clothing/shirt)?
I hope I can find the right team that will tolerate my anxiety and obesity.
Many thanks.
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You can wear your clothes just make sure they're comfortable. I wore a T shirt and sweat pants with warm socks. :) As far as being less sharp, I'm not convinced that is a concern. I am as sharp as I have ever been. Why I don't know but, the treatment didn't affect anything that I can tell.
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Thank you.
One of my main concerns is if the Gamma Knife machine is properly "calibrated" on a daily basis to make sure the beams are going to where they're supposed to go. They doctor in the video below claims to spend a full hour every single morning checking the calibration on a daily basis; however, is this "standard practice" across the nation?
It appears there is a lot of room for error. For example, when the doctor is poking measurement sticks through the helmet and rapidly spouting off the measurements to his assistant. That seems like a prime time for error. I wish they would slow down, or perhaps do it twice to double-check. I guess you just have to "trust your doctor" and the team (which is hard to do when you have anxiety and like to be in control).
Also, my "beer belly" literally scrapes the top of the "open" MRI machine locally in Michigan. This is why I have a valid concern that I won't fit inside the smaller MRI with the GK helmet attached to my head (let alone fit inside the GK machine). I realize it may accommodate my weight, but not the circumference of my huge belly :)
Anyhow, I found this very interesting video regarding Gamma Knife which helped me a lot.
https://www.youtube.com/watch?v=aE56TvJEBOM
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If you can't fit into the MRI at the GK centre, you might need to consider CK where the MRI can be done off site
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If I remember correctly the only part of your body in the GK machine is your head. I don't remember being slid in like an MRI. You are doing quite q bit of research so I would just ask these centers what they think of your situation. Take some measurements and go from there. Same with the calibration. Any of these treatment centers would be happy to answer those questions and concerns I would think. Go right to the source. You don't go into the pre GK MRI with a helmet, just the head frame which is then attached to the table so you can't mover your head. The plastic helmet they put on just simulates the GK columators and they put it on for measurements then take it off. Maybe they can do it open MRI, I don't know and might be facility specific. I'm not that familiar with CK but, the machine hovers over your head so there's probably no size issues there and believe they use a CT scan pre treatment for the planning. As for the anxiety, I wouldn't worry about that during treatment. They will take care of that with some fine medications. From now until then your primary doctor can help you out. I was having a hard time during the research part and with the help of my primary care doctor I was able to handle all that anxiety better and I believe made it much easier during the whole process.
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Thank you everyone for the replies. I really appreciate them.
I believe a big component of Gamma Knife is the excellent imaging available through the "3T MRI" scans immediately prior to Gamma Knife radiation treatment, along with the newer state-of-the-art updated software in the "Leksell Perfexion Gamma Knife machine."
If I can't utilize both of those tools then I would feel like Gama Knife may not be the best option for me. Am I wrong?
I was told if I'm "too big" they can always still do Gamma Knife with a CT "Cat Scan" or perhaps even use an "open" MRI (which is known for much LESS quality imaging); however, those two options diminish the entire point of Gamma Knife in my view.
I mean , sure, they can still "do" Gamma Knife with the less focused CT scan or OPEN MRI, but I would feel like they're kinda going in "half-baked" and guessing (as opposed to using the newest 3T MRI scanner. Obviously there is a big difference in the imaging which has been clearly outlined in the literature.
Plus, I have read on this forum that the newer LEKSELL PERFEXION Gamma Knife machine does make a difference in treatment outcome compared to the older machine.
Therefore, if for some reason I can't fit into the 3T MRI because I'm "too big", I wouldn't feel out-of-line to decline Gamma Knife treatment and opt to have Cyber Knife instead (all things being equal). I want the best for my brain.
Am I wrong in this thinking?
The local "open" MRI I use in Michigan is more rectangular in shape as opposed to cylindrical. My large beer belly literally touches the top of the open MRI when I'm inside. Even the tech was concerned I wouldn't be able to use the open MRI because she claims a magnetic field has to circulate unobstructed around my entire body. We did manage to complete the scan without issue.
If I can barely fit into an open MRI, then isn't it likely I won't fit into a smaller traditional MRI at the GK facility? But then you have to take into account that most traditional MRI's are circular (not rectangular) so perhaps I might fit.
It's bad enough having to go into GK treatment and the MRI in the first place. Having to worry about fitting inside the machine just adds to the anxiety. And having to worry about the quality of imaging also is concerning.
Anyways, I measured my stats. I will be 42-years-old in February. I'm approximately 6'5" tall, 375 lbs, size 42 waist (below the belly) however I'm 64 inches if I measure at the largest point at the belly button. I wear size 16 shoes and my large head is 25 inches around the forehead. My BMI is at 45.
I would think with nearly 2/3 of the country being obese that they would cater some of the MRI machines to the growing population? This also makes me realize that I really need to lose weight in addition to treating my Acoustic Neuroma and Tinnitus.
Another main concern is my Tinnitus. Does anyone know if Tinnitus symptoms "post-treatment" will elevate more if you choose radiation as opposed to microsurgery? Or do both treatment modalities contribute to an increase in Tinnitus (permanent) ?
Finally, when the open MRI technician injected the contrast into my arm she couldn't find a vein claiming it had collapsed (whatever that means!), so she had to use my other arm. When I got out of the open MRI machine and looked at my arm, I was shocked to realize the entire injection-site looked like it was "botched" and severely bruised.
I've had bad nurses botch withdrawing blood from my arm before, but this was different. My entire arm at the injection-site looked like a severely bruised black eye. It was alarming.
Should receiving "contrast" raise any red flags for getting blood clots? I noticed the newer MRI machines inject the contrast automatically through an IV in your arm. And before the contrast is injected, they first inject a "saline solution" to prevent blood clots.
In my case, I never received a saline solution because the tech manually injected the contrast into my arm (with great difficulty); however, it's been 45 days so hopefully a blood clot would have manifested by now if it was going to be an issue.
My doctor has prescribed 1mg Xanax on an "As needed" basis.
Xanax is a miracle drug in regards to my anxiety, and even more so for sleep.
Thanks again for reading. I'm hoping to have all this taken care of and resolved before the start of Spring.
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Hi Mcrue,
The latest 3T machines have larger diameter tunnels. The bigger magnet means they can have a bigger tunnel. If the GK Machine has been made to handle 475lb you would assume that they must have an MRI to handle this too.... The latest Siemens 3T Machine handles 74"... So if you are a mere 64" you should slide in no problem.
Probably time to just get it done, another 0.5mm growth would cancel out any perceived benefit if there is one.
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At least where I was at UVA, they said they would give me anything I needed to get through it. The GK I was in had as much room as the large bore MRI. Not roomy, but better than the regular MRI. I think most places are pretty accomodating, and they might even let you do a test run if you thought it was going to be an issue.