Surgical Salvage after Failed irradiation for Vestibular Schwannoma

[Raydean]

I received this from another group that I belong to.
There has been much discussion and debate between an patients and the AN medical community as to if a AN patient is treated with radiation and the treatment fails subsequent surgery would be more difficult, resulting in poorer outcomes, then  if the patient had surgery directly.

The House Ear Clinic has just published a study to prove it in The Laryngoscope.

The abstract is published below.
Raydean



 Title:  Surgical Salvage after Failed Irradiation for Vestibular Schwannoma

Author(s):  Rick A. Friedman MD, PhD; Derald E. Brackmann MD; William E. Hitselberger MD; Marc S. Schwartz MD; Zarina Iqbal MPH; Karen I. Berliner PhD

Objectives/Hypothesis: Compare vestibular schwannoma (VS) surgical outcome between patients with prior irradiation and those not previously treated. Study Design: Retrospective review with matched control group. Methods: Review of tumor adherence to the facial nerve, facial nerve grade, and complications in 38 patients with radiotherapy as a primary procedure before VS surgical removal and a matched random sample of 38 patients with primary surgery. The majority of the irradiated group had gamma knife radiation therapy. Mean time from irradiation to surgical salvage was 3.3 years (SD = 3.2), with a minimum of 5.2 months and a maximum of 15.8 years. Most (89.5%) patients in each group underwent a translabyrinthine approach. Mean tumor size at surgery was 2.6 cm in each group. Results: The irradiated group had more moderate to severe adherence of tumor than the controls (89% vs. 63%, P ≤ .01). They also had a lower rate of good facial function (House-Brackmann grade I/II) (37% vs. 70%) and a higher rate of poor function (grades V or VI) (50% vs. 18%) at follow-up (P ≤ .019). Results were similar when including only those with good preoperative function (50% vs. 72% and 32% vs. 15%) but did not achieve statistical significance. Surgical time and complications did not differ. Conclusion: Patients who have undergone irradiation for VS and require surgical salvage may have a more difficult surgery and poorer outcomes than those not previously irradiated. When making their initial choice of treatment, patients should be counseled that surgery might be more difficult after failed stereotactic irradiation.

 

[jamie]

Conclusion: Patients who have undergone irradiation for VS and require surgical salvage may have a more difficult surgery and poorer outcomes than those not previously irradiated. When making their initial choice of treatment, patients should be counseled that surgery might be more difficult after failed stereotactic irradiation.

Hi Raydean, I must respectfully disagree, the study doesn't prove anything, it only says that it may be more difficult. It depends on the individual. Second microsurgeries due to regrowth of a resected tumor are also said to possibly be more difficult due to scar tissue.

First, is the tumor more difficult to resect if radiosurgery fails? The answer to this is not clear. Few patients have required resection, and the opinions of the surgeons we have asked indicated that some tumors were less difficult, some about the same, and some more difficult. In a report on this issue that included thirteen patients who had resection after radiosurgery, eight were thought to be more difficult. However, five of these eight patients had failed resection before they had radiosurgery.
http://www.acousticneuroma.neurosurgery.pitt.edu/or.html

I think for a patient looking to avoid brain surgery, the uncertain notion that a surgeon may have a more difficult surgery in the unlikely event radiosurgery were to fail would not be a major factor in the decision making process. Not to mention the uncertain notion that a surgeon may also have an easier surgery after radiation. Just my opinion as a patient who made the decision to avoid brain surgery if at all possible. 

 

[Raydean]

It isn't for me to agree or to disagree.  The information contained with in the study has value and hopefully will be studied more indepth.  In all respect publications go thru a very strict peer reviewed process.  It isn't as if a doctor can pull numbers out of a hat and say "this is so.".  There has to be facts and documentation.  It must be proven to be true.  The numbers and percentages listed in the publication are facts  This study wasn't  about a surgeon having a "more difficult time" but rather about poorer facial and hearing preservations rates for patients requiring surgery following failed irradiation.   

 This chips away at part of the myths.  Perhaps more studies will be done in the future on the above subject as well as statistics on second surgeries.  For myself,
I welcome peer reviewed publications.  I believe that they are valuable research tools.

Again I would like to state that I believe that both surgery and radiation are valuable tools in the treatment of AN's. I'm glad that we live in a time when we have choices.

Raydean
   

[jamie]

There has been much discussion and debate between an patients and the AN medical community as to if a AN patient is treated with radiation and the treatment fails subsequent surgery would be more difficult, resulting in poorer outcomes, then  if the patient had surgery directly.

The House Ear Clinic has just published a study to prove it in The Laryngoscope.

It should be well known to any patient who chooses radiosurgery that surgery after failure could possibly be more difficult. My provider made me aware of that possibility, as should any radiosurgery provider. What I disagree with is the assertion that this study proves surgery would be more difficult, when the study itself says may be more difficult. May or could be is not proof that surgery will be more difficult for every radiosurgery failure. I would also like to see some published statistics by surgeons who practice both treatments, and I will search for some. 

[jamie]

This study wasn't  about a surgeon having a "more difficult time" but rather about poorer facial and hearing preservations rates for patients requiring surgery following failed irradiation.

Here was the conclusion of the study you provided:

Conclusion: Patients who have undergone irradiation for VS and require surgical salvage may have a more difficult surgery and poorer outcomes than those not previously irradiated. When making their initial choice of treatment, patients should be counseled that surgery might be more difficult after failed stereotactic irradiation.

Poor facial and hearing function usually correlates with the difficulty of tumor removal, and it's adhesion to the nerves.

I found a published peer reviewed study comparing the two options, in which surgery following radiosurgery was addressed as well:

The long-term effects of both resection and SRS must be documented to assist in physician and patient decision making. Surprisingly little information has been published on long-term imaging based outcomes after resection. Cerullo, et al.,4 noted a 10% recurrence rate by 10 years following resection. Mazzoni, et al., 22 reported a series of more than 100 patients in whom hearing preservation was attempted. The overall tumor recurrence rate was 8.1%. Although these papers are often criticized for their results, they represent an honest evaluation of longer-term imag-
ing results. All groups should strive to obtain serial imaging studies. Post, et al., 30 found that in four (7%) of 56 patients the resection was incomplete in their attempt at preserving hearing and that in three regrowth developed within 3 years. In the largest series, Samii and Matthies 32
reported a complete resection in 98% of patients and documented recurrence in six of 880 without NF2. In our SRS series, 98% of the patients required no further surgery and in 94% there was imaging confirmation of persistent tumor control. Tumors that increased in size in the 1st or
2nd year after GKS did so usually in association with central tumor necrosis, with a small expansion of the tumor capsule. Most such tumors then regressed to a size smaller than that at baseline with longer follow up. Such transient expansion may be associated with transient retroauricular pain, perhaps due to regional dural inflammation.

Recurrence or continued tumor growth may follow resection or SRS, and periodic neuroimaging studies should be obtained in all patients.

We believe that all patients with newly diagnosed, residual, or recurrent acoustic tumors ( 3 cm in extracanalicular diameter) are now suitable candidates for SRS. 8,17 Larger tumors are not as good candidates because of the dose reduction necessary to reduce the rate of potential radiation-related side effects. Hearing preservation should be attempted in younger patients with good hearing, either with SRS or resection. 31 In our first 3-year experience, we accepted elderly patients, those with concomitant medical problems that argued against resection, those with residual or recurrent tumors after resection, and those with preserved hearing function. By 1991 we began to offer radiosurgery to all patients with acoustic tumors regardless of age, surgical history, or symptoms. For older patients (age 75 years) with small and minimally symptomatic
tumors, we continue to advocate observational serial imaging–based evaluation. 2,33,39

When we evaluate patients with acoustic tumors, many ask the following two questions. First, is the tumor moredifficult to resect if GKS fails? The answer to this is not clear. Few patients have required resection, and the opinions of the surgeons we have asked indicate that some tumors were less difficult, some about the same, and some more difficult. In a report on this issue that included 13 patients who had undergone resection after SRS, eight lesions were thought to be more difficult to treat. In five of these eight patients, however, resection failed before they underwent radiosurgery.

http://64.233.167.104/search?q=cache:grylQgTdWqsJ:www.aans.org/education/journal/neurosurgical/may03/14-5-1.pdf+surgery+difficult+radiosurgery+study+acoustic&hl=en

Some neurosurgeon opinions from the AN archive:

The tumor tissues killed by radiosurgical treatment have texture that is different from that of live AN tissues.  A surgeon who is used to working with this texture should find it no more of a problem. However, an inexperienced radiosurgeon may not be used to this texture, and might find it harder to work with for this reason:

Several surgeons told us that removing an irradiated tumour was harder than removing a non irradiated one if you had to have this done... Dr. Williams advised us this was not the case, as did Doctor. A good surgeon should have no great difficulty.

The neurosurgeons I talked to said the surgery was different but not more difficult and that any surgeon that said it was more difficult didn't have enough experience.

Dr. Slattery at the HEC said that it would not be any harder. I was surprised as that was counter to what I had heard.

Dr. Chang at Stanford performs both traditional surgery and radiosurgery (Cyberknife) on acoustic neuromas. He said it is false that it is more difficult to perform surgery after radiation.

Note that the same issue exists for repeat surgery, since the first surgery usually leaves behind scar tissue with different texture. It is well known that repeat surgeries can be more difficult because of this scar tissue. In either case, seeking an experienced surgeon is the best way to prevent problems - or opt for a second radiotreatment instead.
http://www.anarchive.org/myths.htm

Thank you for posting that study Raydean, and I don't mean to come across as confrontational. That House study is a good tool in the decision making process, but it is misleading to say it proves that surgery will result in poorer outcomes after radiosurgery. It only proves that a percentage of surgeries following radiosurgery result in poorer outcomes. That is an important detail that a patient must be aware of, but it would be wrong for them to believe if radiosurgery fails surgery will be more difficult.