Stats on CK,GK, long term?

[Greg M]

Hello crew, I was wondering if anyone knows the long term Stats on the CK, GK, treatment? What are the long term stats on regrowth (non-death of tumor) and side effects? 10yr, 20yr (is the CK 20yrs old yet?), 30yrs (GK)? Is radiation a long term healer? Any comments welcome. Thanks Greg

[carter]

i have heard different numbers for regrowth --- the most widely used number is approx 2%.  this has included regrowth and failure to "kill" it!!!! 

as to complications ....  one would have to define a complication  ..... i have hearing loss in the AN ear ....  if the hearing decreases some more, is this due to the radiaiton or the growth of thr tumor before it died?   others would argue if the issue is a result of the radiaiton or something else.  also there is the issue of what is defined as a success by the doctor ...  i was told that it was a successful surgery if the nerve for the face control was still in tact ... to me it would be a greater mesure if the nerve functioend properly.  i have no one given me this percentage in a manner that i trusted.  if you do hear this percentage - ask what was a success vs a complicaiton and where the list of complications are listed.

i made my own check list ...  i went through the past postigns and listed the stated complicaitons for radiaitona nd for surgery.  this is not scientific - but this became a point on my decision analysis.

so to throw a monkey wrench vs an answer.



carter

[macintosh]

Greg—
When I found out I had an AN two years ago, I asked the same questions. I was surprised to discover, as Carter says, that the research is kind of scattered—lots of places give statistics for their own patients, but not everybody uses the same standards, especially when it comes to what counts as hearing preservation. I found it difficult to find broad, comprehensive studies (although I’d love to hear of something that I missed).
Anyway—my general sense is that a 2% fail rate is optimistic, but maybe some places actually do that well. I’m going to paste in a couple of excerpts from an article in the Journal of Neurosurgery November 2006 by Dr. William Friedman at Shands Hospital, University of Florida and an editorial comment by Dr. Jason Sheehan at University of Virginia that I think are typical of self-reporting. I’m also putting in the link to Sheehan’s summary essay. You can find more articles at pubmed.gov, which lists peer-reviewed research in journals like this one.

http://thejns.org/doi/full/10.3171/jns.2006.105.5.655

From Friedman: The long-term tumor control rates (90% of tumors were unchanged or smaller; 99% required no further surgical intervention during the follow up) and the cranial nerve morbidity rates (0.7% with doses used since 1994) greatly exceed the published results of even the most experienced surgeons. The issue of malignant tumorigenesis has recently been the subject of much discussion. It probably exists but at a frequency tremendously lower than the risk of a serious complication from open surgery. Let’s use our hard-won microsurgical skills on larger tumors and accept the facts about radiosurgery discussed in our paper and many others.
From Sheehan: In their article in this issue of the Journal of Neurosurgery, Friedman and colleagues add to the neurosurgical literature by detailing their experience with linear accelerator–based radiosurgery in 390 patients with VSs. The 5-year actuarial tumor control rate was 90%. They noted a 4.4% rate of facial weakness and a 3.6% risk of numbness following radiosurgery. After adopting a prescription dose rate of 12.5 Gy, rates of facial weakness and numbness each decreased to 0.7%.
At the University of Virginia, more than 400 patients with VSs have been treated with Gamma Knife surgery (GKS); the results of some of these cases have been reported previously. Among patients treated primarily with GKS a decrease in tumor size was seen in 81%, no change in 13%, and an increase in 6%. In patients treated with GKS after microsurgery, a decrease in tumor size occurred in 65%, no change in 25%, and an increase in 10%. Notably, although our experience in treating large VSs (that is, tumors ≥3 cm in diameter) is minimal, we have observed a 95% tumor control rate in such cases after GKS. Such a result for these large lesions in patients unfit for microsurgery was unexpected.
Among the patients at the University of Virginia, permanent changes in trigeminal sensation occurred in 1.7% and facial paresis occurred in 1.5%. Of the patients with useful hearing before GKS, 58% retained it after radiosurgery, 42% experienced some degree of deterioration, and 31% lost useful hearing.

Hope this is helpful,

Mac

BTW--I had my small AN zapped by Friedman two years ago--minimal, temporary side effects, starting to show shrinkage at last MRI.

[allegro17]

Hi Greg,

Not much to add, but I just wanted to let you know that we do seem to be in the same boat!  I spend hours a day doing research and hope eventually I will be able to  feel comfortabe with a decision.
One of the problems I have encountered is that there seems to be a lot of "different" information.  I have seen quotes of up to 98% tumor control, then seen  others that look more like 90%.  And I'd love to know what EXACTLY tumor control means.  I have heard from some doctors that there would not be any reason to believe a tumor that has been "controlled" by radiaton for 5 years or more would ever continue to grow, and then doctors who have said that the further out you get from the procedure in years, the greater the chance of regrowth.  It makes it hard to feel like I can make a decision based on facts.  for whatever reason, it seems like the stats for surgery are much more strightforward, which could be either because there is more history to base them off of, or maybe its just my head playing ticks on me
In the end, I think what it comes down to is that the treatment options have been advancing over the years to a point that are now all relatively equal.  The biggest issues for me at this point are:
Experience of the doctor
Lack of long term follow up for radiation (and my comfort level wih that)
Invasiveness of surgery and recovery time (and my comfort level with that)
Those are the things I am going to try to start focusing on after weeks and weeks of reading all of the medical literature and see where it gets me
Good luck to you and keep us posted

Laura 

[carter]

groups play games with the statistics ... that much is true.

the purpose of ck is not to reduce tumor size / shrink it.... it is to control it or stop its growth.  so this is a measure that should be reviewed for CK and GK ---- but as teh majority of drs/clinics want to sell their wares - they will find stats to prove what ever they wish to sell ... 

yes i am not happy with our medical system - but it is what i have to work with .... 

[sgerrard]

Over the long haul, radiation does about as well as surgery at controlling tumor regrowth, at least in some of the studies and at some of the facilities that do it. Like surgery, it is not perfect, and given enough time, some tumors will grow back.

You can only take the statistics so far. According to statistics, you don't even have an AN, since getting one this year is a 1 in 100,000 long shot.    What you can do is pick a reasonable course of action - watch and wait, or treat with radiation, or have it surgically removed (or both, in some situations). In many cases, treatment is the end of it, and the side effects are acceptable. Occasionally it turns out less well. You can only give it your best shot.

What is your gut instinct telling you?

Steve

[FlyersFan68]

Gamma Knife wasn't used in the USA until 1987 and really started taking off for AN's in the mid-nineties. However, it was created in Germany in 1967.  Univ. Of Pitt. has the longest track record in the USA being a little over 20 years. Cyberknife was FDA approved in either 1999 or 2000. The two best places for statistics would be Univ. of Pittsburgh for GK and House Ear Clinic for surgery. Each heavily favor their approach. In a few years Stanford should be publishing their ten year track record. These centers would likely have the largest follow up since they see so many patients like ourselves. We have to be careful with any of these procedures regarding statistics. To me, they always seem to sway "there way". Side effects do vary no matter which procedure you choose. Personally, I try not to think about long term. My AN is gone through surgery but if I had radiation instead I wouldn't be thinking about long term either. After your decision is reached you have to live with the results no matter what. 

[GRACE1]

Dr. Lars Leksell of Sweden developed the concept of radiosurgery in the 1950s.  The first prototype of Gamma Knife was installed in Sweden in 1968.  GK has been used on thousands of patients since then, so I know there must be numerous statistics on long-term results.

When my AN was first diagnosed, I did a lot of research on GK and Dr. Leksell when I decided that was the treatment for me.  I even corresponded with either his son or grandson, also a neurosurgeon, in Sweden.  He was most gracious.

Dr. Leksell was a class act to me.  He died peacefully at 78 in 1986 while taking a brisk walk in Swiss alps.

Grace

[mk]

There is a recently published review, where the authors collected data published by various institutions. Here is the abstract:

Weil, R S. Cohen, J M. Portarena, I. Brada, M.
 
Title Optimal dose of stereotactic radiosurgery for acoustic neuromas: A systematic review.
 
Source British Journal of Neurosurgery. 20(4):195-202, 2006 Aug.
 
Abstract Radiosurgery is increasingly employed in the treatment of acoustic neuroma, but the optimal dose in terms of long-term tumour control and minimal adverse effects has not been established. We performed a systematic review of the published literature of radiosurgery of acoustic neuroma to assess whether the use of low dose radiosurgery is as effective as high dose treatment. Reports of radiosurgery for acoustic neuroma were identified through a Medline search. Studies with at least 15 patients and a median follow-up longer than 12 months were included. The relationship between actuarial 5-year progression-free survival (PFS), and tumour and treatment parameters was examined. Forty-two studies were included. Tumour control following lower radiosurgery doses was similar to that reported following high doses. Only 12 studies reported actuarial outcomes at 5 years. There was no relationship between PFS at 5 years and dose to the tumour margin. Radiosurgery of larger tumours was associated with lower 5 year PFS (p < 0.05). Although on initial inspection radiosurgery of acoustic neuroma with doses of 12 - 13 Gy seems to be as effective as higher dose treatment, the available reports are subject to a number of confounding factors, are not sufficiently statistically powered and there is only limited long-term actuarial outcome data. Currently, available studies do not provide sufficient confidence to support the claim that low dose radiosurgery is equally effective as higher doses in the long-term control of acoustic neuroma.

According to this study, data prior to 1989 were excluded, because they include very few patients. It should be also kept in mind that radiosurgery was only used for elderly patients, so long term follow up would be difficult.
This article is full of confusing stats, so it will take some time for me to digest. It also mentions progression-free survival (PFS) and actuarial control rates, and I am not sure what either of those mean.

Here is the abstract from the article published by Pittsburgh, which includes the longest spanning study from what I can tell:

Radiosurgery of vestibular schwannomas: summary of experience in 829 cases
L. DADE LUNSFORD, M.D., AJAY NIRANJAN, M.B.B.S, M.S., JOHN C. FLICKINGER, M.D.,
ANN MAITZ, M.SC., AND DOUGLAS KONDZIOLKA, M.D., F.R.C.S.
Departments of Neurological Surgery and Radiation Oncology, The University of Pittsburgh School of
Medicine; and The University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
Object. Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience. Methods. Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection,
imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10–20 Gy). No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day.
Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed). Conclusions. Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.

All the other long-term publications that I could find come from Japanese and Chinese groups.

Sorry about the long e-mail, it seems that there it a lot of interest on this topic lately.

Marianna