How big is too big for Gamma Knife?

[v357139]

I have 2.7 cm, pressing on cerebellum and brainstem.  Is that too big for GK or other type of radiation?  Also, has anyone had one pressing on brainstem, and used GK or other radiation?  Isn't there a risk the tumor would swell, and compress the brainstem?

[arizonajack]

2.7cm is about the size of a 25 cent piece.

My guess is that it's too large for radiation.

But you seem to already know that.

"Recently diagnosed left side, 2.5cm acoustic neuroma.  Went to doctors at three top NYC hospitals and they all recommend surgery, retrosigmoid.  They say its too big and pressing against brain, so radiation or gamma knife are not good option options.  I believe them.  Funny thing is they all say I should not be able to hear by now, but I can still hear fairly OK in that ear.  One doctor said the MRI shows it is not that deep in ear canal, and that is why.  So I am good with retrosigmoid to try and preserve hearing."

[rupert]

My AN was 2.2 x 1.6 .  It was pressing on the brain stem pretty good by the looks of the MRI and what I was told.   I had GK in 2010 and happy to say the AN is now starting to receed off the brainstem.   Expert neurosurgeons with GK experience will be able to tell you if you're a good candidate or not.   Usually the cut off is 3cm.  But places like UPMC are going beyond that in some cases.

[PaulW]

Here is a link from the International Radiosurgery Association
http://www.irsa.org/acoustic_neuroma.html
It shows tumours of less than 3cm qualify.

The safe cutoff is actually based on tumour volume and 12.5cm3 is typically the safe cutoff.
This means that some tumours that are odd shaped with one dimension bigger than 3cm can safely qualify.

Some people I believe have had larger tumours radiated.

[v357139]

2.7cm is about the size of a 25 cent piece.

My guess is that it's too large for radiation.

But you seem to already know that.

"Recently diagnosed left side, 2.5cm acoustic neuroma.  Went to doctors at three top NYC hospitals and they all recommend surgery, retrosigmoid.  They say its too big and pressing against brain, so radiation or gamma knife are not good option options.  I believe them.  Funny thing is they all say I should not be able to hear by now, but I can still hear fairly OK in that ear.  One doctor said the MRI shows it is not that deep in ear canal, and that is why.  So I am good with retrosigmoid to try and preserve hearing."

I thought i knew that.  But I am hearing that surgeons don't always recommend radiation.  So I am seeing a GK doctor Kondziolka tomorrow, just to see what he says.

[v357139]

My AN was 2.2 x 1.6 .  It was pressing on the brain stem pretty good by the looks of the MRI and what I was told.   I had GK in 2010 and happy to say the AN is now starting to receed off the brainstem.   Expert neurosurgeons with GK experience will be able to tell you if you're a good candidate or not.   Usually the cut off is 3cm.  But places like UPMC are going beyond that in some cases.

Did they advise you of any risk of tumor swelling after GK, and that might be dangerous?

[rupert]

Dr. Kondziolka did my GK procedure .  They figure possible swelling into the equation.   My AN never swelled at all.   Was about 1mm smaller at 1 year and 2mm smaller at 2  years.  Kondziolka is one of the best out there.  Good luck.

[mk]

Technically the cut-off in N. America is 3 cm, but this will depend on the center. Some centers have a lower cut-off. As Paul said the volume is more important. Some centers in Japan have reported radiation in tumors as large as 15 cc, but this is not generally accepted practice.

Sometimes for larger ANs the radiation oncologist may choose to use a smaller radiation dose to avoid swelling. In my case they used 11 Gy instead of the common 12-13 Gy. The downside of this is that the chances of success of the treatment go down. This is exactly what happened in my case. I didn't have swelling, but the treatment failed.

Some believe that CK or FSR treatments are better to avoid swelling in larger tumors. If you are indeed interested in the radiation option, I would suggest to consult further with Dr. Chang at Stanford and perhaps with a centre that does FSR.

Overall I think that over the years we had a few (not too many) people here who had FSR/CK for bigger tumors with successful outcomes.

Marianna

[v357139]

Kondziolka said I am a good candidate.  Said he did not think the swelling would cause any major problem.  Said he never had someone he treated need emergency resection, which was a big concern for me.  Gave me 99% chance of good facial function, and 98% tumor control.  Said he would use 12 units.

This is a bit shocking to me.  Previous surgeons that do both surgery and gamma knife said mine was borderline, and the swelling could cause a problem, and they did not recommend it.  Is there anything good to read up on this?

[rupert]

I can't recall ever  hearing  any cases where an emergency resection had to be done after GK because of swelling.  Some swell and some don't.  Kondziolka  is an expert at GK,  he is also a well respected neurosurgeon that preforms many other surgical procedures other than GK.  So he is not just one sided towards GK.  He is one of the best and I would value his opinion.   Dr. Lunsford at UPMC is another very well respected GK expert in Pittsburgh if you're looking for another opinion you can send your scans there and they will get back to you in a week or two.

[v357139]

I had seen some posts in AN Arhcives, which is a pro radiation site, that talked about emergency surgery needed after FSR and proton beam.

That is a great lead on GK second opinion.  Thank you very much.  Any idea where I would consult for FSR?

[nftwoed]

Hi;

   A few will do fractionated GK.

[PaulW]

One of the advantages of single fraction and to a lesser extent 3-5 fractions, is that radiation can be repeated if the first treatment fails.
This is due to the low overall dosage received by the healthy tissue.
If you get FSR, it will possibly exclude you from further radiation treatments.

One of the advantages of single fraction over FSR which could be 30 fractions, is that with single fraction all tumour cells get hit at once. If you receive radiation over a 4 week period, new cells could be "born" halfway through the treatment, and they will never receive enough radiation to kill them. FSR does put you at higher risk of regrowth as a result.

[v357139]

I can't recall ever  hearing  any cases where an emergency resection had to be done after GK because of swelling.  Some swell and some don't.  Kondziolka  is an expert at GK,  he is also a well respected neurosurgeon that preforms many other surgical procedures other than GK.  So he is not just one sided towards GK.  He is one of the best and I would value his opinion.   Dr. Lunsford at UPMC is another very well respected GK expert in Pittsburgh if you're looking for another opinion you can send your scans there and they will get back to you in a week or two.

I am having second thoughts on GK.  When I look at my MRI, I see the tumor so embedded in the cerebellum, and pushing on the brainstem.  I know I am not a doctor.  But if it swells alot, I cannot believe that it would not cause problems.  Dr K said it would not, but when I look at the pictures, its hard to believe swelling would not cause a problem.

[rupert]

If you saw my MRI you would see the same thing you describe.  Most AN's of that size and even smaller, are pushing on the brain.  Look, I'm not trying to talk you in to anything but after several years on this forum I have seen too many people try and self diagnose treatment.  You need to heed what qualified medical people who specialize in AN's are saying. Unless you stayed at a Holiday Inn Express recently of course.     Dr. K knows of what he speaks as hundreds and hundreds of patients can attest.