Large AN: radio-short term hearing preservation, surgery-long term tumor control

[Bomberman]

I've done a good amount of research now and have started to form conclusions. I've talked to 3 neurosurgeons, 2 radiologists (Linac and CK), 1 GK technician and I'm starting to conclude the main difference between the 2 approaches. These are my thoughts on surgery vs radio.

Surgery: good for those who prefer long term tumor control/removal
Radio: good for those who prefer short term hearing preservation (long term is unknown)

Surgery is better for those who don't want to deal with anything down the line, because it can remove everything, or at least give you a chance for GK down the line which is pretty good one shot procedure.

Radio is better for hearing preservation because the numbers support higher rates of hearing retention. However data is only available for the last 10 years and the trend seems to be going downhill over time. At the same time it doesn't have good long term control because larger tumors have higher chances of regrowth. Secondly, if there is regrowth, further radiation cannot be done because effects of previous radiation is already there. There is also a tiny chance of new tumors resulting from the radiation. Thirdly, the resulting scar tissue complicates future surgery because it no longer has the same characteristics as an untouched AN such as softness, and delineated edges. Someone previously asked, what is the elephant in the room. I think this is it.

[Blw]

There are many many variables that you have to account for with both procedures, so you have to be careful to make sure you are comparing apples to apples. Tumor size is important. Location. The nerve it originated from. All things being equal, the two approaches have very similar outcomes. There is an upper size limit beyond which radiation is not recommended, and if the tumor is on the facial nerve, surgery is most likely the second choice. The key component is tumor control. Surgery can often get it all out, then you are done with it, but it can also fail and you get regrowth. Surgery can also preserve hearing depending on strategy, but it can also destroy it. True, that a radiation failure makes surgery harder, but it does not always rule out a second radiation. Some people are not concerned by surgery and want it all out and over with. Others do not want the invasiveness of surgery. The best approach is get as many opinions as you can, then when you decide on a strategy, go to the absolute best doctor that you can, even if you have to travel. Keep in mind surgeons want to operate and radiators want to radiate. Try to find one person that does both so that you can reduce bias. Read as much as you can here, and go through the two different sections; surgery and radiation. Lots of pros and cons. Also, some misconceptions can be corrected. If you know how to use PubMed (the NIH literature search site), go there and use the review function in your searches so you can read large clinical studies--reading single case reports doesn't tell you much and there are thousands. Many journal articles do not allow public access, but many do if they were funded by NIH.

[Citiview]

How large is your AN?
I agree with BLW (the whole post) but especially choose the best doctors. Now is the time to be discriminating and get the best team.

I think hearing preservation is hit or miss. Some people lose hearing in middle fossa surgery (supposedly the best for preservation). Others have very large tumors and somehow retain hearing with surgery. I think there is a lot they don't know about hearing preservation and the science is constantly evolving.

I notice there are a few centers that are attempting cochlear implants with acoustic neuroma surgery. I'm sure it's in the beginning stages and experimental.

Good luck.

[rupert]

   A couple of things.  Your post contains a lot concerning hearing preservation.  Hearing preservation and AN's don't seem to like each other.  I'm sure I sound like a broken record if you read my other posts but, chances are that no matter what procedure you have done your hearing is going to go away some or all.  That's just the way it is with AN's,  they are hearing killers.   Some people do come out pretty good but, most will not.  The Docs are certainly trying,  and new techniques happen all the time.  Maybe someday there will be better outcomes.
   As far as your thoughts on radiation.  I think some of your conclusions are wrong.  After GK or CK treatment the chance of regrowth is very slim.  Exactly the same as surgery by the way. The tumor may,  or may not be any harder to remove if need be.  Some of the best doctors say that it makes no difference.  Some are naturally harder to remove regardless of treatment.  GK has been around a long, long time and there are certainly long term studies on it.  Hearing preservation is kind of a new thought as far as treatment regardless of radiation or surgery. Again, that's a new concentration the doctors are constantly working on but, not much success yet.

[Bomberman]

If you know how to use PubMed (the NIH literature search site), go there and use the review function in your searches so you can read large clinical studies--reading single case reports doesn't tell you much and there are thousands. Many journal articles do not allow public access, but many do if they were funded by NIH.

Can you tell me what is the review function?
Anyway to get private access?

[Blw]

The pub med site is here:
<https://www.ncbi.nlm.nih.gov/pubmed/>

Copy and paste this in
vestibular schwannoma

hit search

On the left column, top, is a heading that says article types. Select review

To read the summary of each article click the blue links. If the article has a button on the right that says PMC full text, you can read the whole article.

As a shortcut, after selecting review, there is another heading under article types called text availability. If you click free full text, only the ones that are free and have the whole article will appear.

If you want to increase specificity, use "and" as a modifier, such as Vestibular schwannoma and radiation. You could also do vestibular schwannoma and gamma knife. Also, vestibular schwannoma and surgery.

There are ways to make it even more deteailed, but start with this and you'll learn as you go along.

[Blw]

A minor point that people who are really concerned with hearing might consider. As was noted, hearing an ANs don't go well together and the norm is to have much worse or no hearing after it is all over. With surgery, you could wake up without hearing if they cut the nerve, and sometimes they tell you that going in. With radiation, assuming you are starting with reasonable hearing, it can take years to lose it--not a good outcome, but gradual hearing loss helps your brain adapt to the changes easier. I think some of the numbers quote a rate of 50% useable hearing after 5 years. I'd take that in a minute.

[Bomberman]

I followed Blw's advice and I've compiled numbers between FSR and retrosigmoid surgery. They take into account regrowth and salvage therapy chances.

                                        Retrosigmoid   FSR
facial nerve perservation   96.7%             91.1%
hearing preservation         24.6%             46.9%

Calculations:
96.7%:
Facial nerve preservation stands at 97% http://thejns.org/doi/pdf/10.3171/2011.7.JNS101921. n=383
Regrowth rate of 13.2% http://thejns.org/doi/pdf/10.3171/2011.7.JNS101921. n=383
Salvage GK 94.6% (.94/.994 post op 50months) from https://www.ncbi.nlm.nih.gov/pubmed/25065850 n=159
0.97x86.8 + 0.946x13.2 = 96.7%

24.6%:
19.2% hearing preservation from https://www.ncbi.nlm.nih.gov/pubmed/25065850 n=159 supported by https://www.ncbi.nlm.nih.gov/pubmed/23749017 n=32
Regrowth rate of 13.2% from above
Salvage GK of 60.4% = 11.6/19.2 https://www.ncbi.nlm.nih.gov/pubmed/25065850 n=159
0.192x86.8 + 0.604x13.2 = 24.64%

91.1%:
Facial nerve preservation stands at 94% from https://www.ncbi.nlm.nih.gov/pubmed/26508404
There is an 8% chance tumor is not controlled https://www.ncbi.nlm.nih.gov/pubmed/26508404, supported by https://www.ncbi.nlm.nih.gov/pubmed/22921979, and https://www.ncbi.nlm.nih.gov/pubmed/21353158
Salvage surgery preserves facial nerve at 57.4% (0.5x0.795 + 0.857x0.055+0.857x0.151) from https://www.ncbi.nlm.nih.gov/pubmed/21897324 n=73
0.94x92 + 0.574x8 = 91.1%

46.9%:
Hearing perservation is at 51% for large tumors https://www.ncbi.nlm.nih.gov/pubmed/25077322 n>4000 patients
Other studies show 0.43 = (24+60)/(85+109) from  https://www.anausa.org/component/docman/doc_download/448-2014-patient-survey-report-final?Itemid=357 n>1000
Ck reports 77% https://www.ncbi.nlm.nih.gov/pubmed/19751871
57% from https://www.ncbi.nlm.nih.gov/pubmed/19303780 n=254
Interesting that class 2 Koos is 47% https://www.ncbi.nlm.nih.gov/pubmed/15179283 n=1000
8% chance tumor is not controlled.
Salvage surgery makes hearing preservation impossible: https://www.ncbi.nlm.nih.gov/pubmed/23177377 n=19
0.51x92 + 0x8 = 46.9%

Notes:
I tried to cater this to large ANs (mine is 2.9cm).
Regrowth rate of surgery is a little bit higher because Dr. Sisti tends to be on the conservative side in saving nerves and leaving more behind.
The numbers for radio will go down over time as the longer it is, the trend is the higher the chances for regrowth and so far we only have less than 10 years of data.
Let me know if you see some numbers that can be more accurate.

[rupert]

Sorry, I can't make heads or tails of your post.  What are you trying to compile?  Are these statistics  for one particular doctor?   I think there is no way to compile statistics.  There are soooo many variables between Doctors, experience, size, medical history and such that  there is just no way to get real accurate data.  As far as less than 10 years of data on radiation treatment, I'm not sure where that came from. Is that for one particular doctor?  I'm sure there is at least 40 years of data.   

[Bomberman]

Sorry, I can't make heads or tails of your post.  What are you trying to compile? 

I'm compiling the chances of losing nerve functions between retrosigmoid and radiation.

Are these statistics  for one particular doctor?   I think there is no way to compile statistics.  There are soooo many variables between Doctors, experience, size, medical history and such that  there is just no way to get real accurate data. 

Facial nerve preservation may be better than average since the study comes from a doctor who is more conservative on leaving tumor behind. But it won't be more than 2% difference. The other stats were not based on any particular doctor.

As far as less than 10 years of data on radiation treatment, I'm not sure where that came from. Is that for one particular doctor?  I'm sure there is at least 40 years of data.

You're right there is 40 yrs of data for gammaknife. I'm just talking about FSR data.

[Jet747]

Bomberman,

Interesting post, now I'm going to have to do some compiling and set analysis of this data, which I admit is hard to control for all factors.

I had a pretty good size tumor coming in at 6.2cm.  18 months later my hearing is about the same as pre-surgery/radiation.  >95%.

To further complicate your analysis though let's throw in one more alternative treatment scenario...surgery & radiation.

I had debulking RS surgery followed by GK 6 months later.  This might be the best of all treatments (preserving hearing & other) or the worst of all treatments (increasing future probabilities of problems with another surgery)...only time will tell, even then environmental factors probably play a part in outcomes, one small (possibly irrelevant) example is I had 3 good size cysts around my tumor, now did these hurt or help the short term outcome? Long term?

Right now I can only say, so far so good.  I concede, I'm only 18 months removed from the surgery and could very well be facing another surgery or hearing loss in 10 years or less.  If surgery is required I'm ok with it, certainly it is not a walk in the park but its not the end of the world either.

Being a numbers guy, I like your data driven approach.

If your interested, you could check out a couple of the research studies on the main AN web site to see if your specific case qualifies.  I'm currently enrolled in the Mayo study where they are looking at long term quality of living for AN patients.

Anyways, good post and good luck with whatever approach you choose!

Best,
Jet

[Bomberman]

Hi Jet,

To further complicate your analysis though let's throw in one more alternative treatment scenario...surgery & radiation.

Actually this is the scenario with my RS numbers. It takes into account debulking surgery, and then the chance of GK afterwards. If you already have had GK, then I think you are pretty much in the clear. As GK numbers have nearly 0% regrowth rates from what I remember. May I ask who did you have your treatments with?

I had debulking RS surgery followed by GK 6 months later.  This might be the best of all treatments (preserving hearing & other) or the worst of all treatments (increasing future probabilities of problems with another surgery)...only time will tell, even then environmental factors probably play a part in outcomes, one small (possibly irrelevant) example is I had 3 good size cysts around my tumor, now did these hurt or help the short term outcome? Long term?

My numbers were not specific to cysts. Btw, congratulations on your exceptional outcome. 6.2cm and still with hearing! From what I have read, it sounds like you are pretty much in the clear in terms of regrowth, ie. no more treatments.

[Jet747]

May I ask who did you have your treatments with?

Dr.  George Bovis out of the Brain & spine center.  Excellent neurosurgeon.  Highly recommend if your near Chicago.

My documented case thus far:

https://www.anausa.org/smf/index.php?topic=21969.0

My numbers were not specific to cysts. Btw, congratulations on your exceptional outcome. 6.2cm and still with hearing! From what I have read, it sounds like you are pretty much in the clear in terms of regrowth, ie. no more treatments.

Let's hope so!  18 month MRI coming in 1 week.

Be well,
Jet

[ANSydney]

Bomberman,

I like your use of probabilities. To me, that's the only way to make sense of this mess.

I get the feeling that the first column was retrosigmoid, but morphed into retrosigmoid followed by radiosurgery.

I would have the table as follows:
                                      Retrosigmoid
                                    +radiosurgery    radiosurgery
facial nerve preservation      92.3%             97.3%
hearing preservation            11.6%             55.8%

That gives retrosigmoid + radiotherapy a 2.9 times higher failure rate for facial nerve and twice the failure rate for hearing preservation. You may want to look at trigeminal neuropathy.

The reasoning for the altered figures is as follows:

Retrosigmoid then radiosurgery facial function preservation

http://thejns.org/doi/pdf/10.3171/2011.7.JNS101921, facial nerve preservation is 96.6% not 97%. Not much of a difference, but to me it suggests bias. Other figures go to a decimal point after the integer, but not this one.

Also, n = 151, since of the 383 patients, 151 commenced with microsurgical resection.

ttps://www.ncbi.nlm.nih.gov/pubmed/25065850 n = 151 since only 151 patients were followed postopersative. The preservation of facial function was 142/151 = 94.0%

I’ll add another interesting paper which is http://www.karger.com/Article/Abstract/447520 from 2106, n = 22, which shows facial function preservation in 86.4% of cases.

Given them equal weight, retrosigmopid + radiosurgery has facial function preservation at 92.3%. So, personally, I would have this figure rather than 96.7%

Retrosigmoid then radiosurgery hearing preservation

https://www.ncbi.nlm.nih.gov/pubmed/25065850, n = 129 has hearing preservation at 11.6%
https://www.ncbi.nlm.nih.gov/pubmed/23749017 is not applicable since it’s for retrosigmoid only.

Radiosurgery facial function preservation

https://www.ncbi.nlm.nih.gov/pubmed/26508404 has facial function preservation at 94 to 100%. In the absence of other information , let’s call it 97%.

https://www.ncbi.nlm.nih.gov/pubmed/21353158 has facial and trigeminal nerve preservation >95%. Taking out the trigeminal nerve and considering the > sign, let’s also set this at 97%.

I’ll add two interesting paper which are http://bmjopen.bmj.com/content/3/2/e001345.full.pdf+html which has facial neuropathy at 1% and http://appliedradiationoncology.com/articles/interdisciplinary-management-of-acoustic-neuromas which has facial aspects at 96%

Radiosurgery hearing preservation

https://www.ncbi.nlm.nih.gov/pubmed/25077322 n>4000 patients, for marginal does <13 Gy, has hearing preservation sat 60.5%. Marginal dose is something that under your control.

https://www.anausa.org/component/docman/doc_download/448-2014-patient-survey-report-final?Itemid=357 n>1000 appears to have hearing preservation at 30.5%

https://www.ncbi.nlm.nih.gov/pubmed/19303780 n=5825 has a hearing preservation at 59%

The same two interesting papers http://bmjopen.bmj.com/content/3/2/e001345.full.pdf+html which has hearing preservation at 52% and http://appliedradiationoncology.com/articles/interdisciplinary-management-of-acoustic-neuromas which has hearing preservation at 63% (Table 2) and 70% (Table 3)

Given them equal weight results in a average of 55.8%.

This flips things in favour of radiosurgery only.

Regards.

[Bomberman]

Hi ANSydney,

You are correct, I did combine retro + radio in the chance of failed retro in the first column. And in the second column I did radio + retro in the chance of failed radio.

I didn't see 96.6% in the paper. I only see 97% in there so that's why I used it. You are right after I divided the numbers. But even so, not much difference anyway. You are right, n = 151, not 383. Facial function preservation I see at 146 instead of 142 on page 5 of the PDF. Where did you see 142?

n=22 of the 2016 is too small of a statistical sample size for me. I was taught that n=30 is the minimum. What you can do however is add the 22 and combine with the 151 and average weight those two.

The number you have at 11.6 hearing preservation is only for those who had failed surgery. Those who did not have failed surgery have higher preservation rates so you have to weighted average those two numbers.  It should be higher than 11.6.

For your number 55.8, you didn't include the chance that there is tumor regrowth. In this case, hearing preservation is impossible. That should lower your number. This is the same also with your facial nerve preservation number.  Also as time goes on the chances for tumor regrowth from radiation increases, and the larger the AN the chances also increases.