Hearing preservation in earlier treatment

[Blw]

Lunsford is the world expert on Gamma knife. This is a study of radiating AN patients early in their course when their hearing is still unaffected.

Int J Radiat Oncol Biol Phys. 2016 Jun 1;95(2):729-34. doi: 10.1016/j.ijrobp.2016.01.019. Epub 2016 Jan 19.
Early Radiosurgery Improves Hearing Preservation in Vestibular Schwannoma Patients With Normal Hearing at the Time of Diagnosis.
Akpinar B1, Mousavi SH2, McDowell MM3, Niranjan A3, Faraji AH3, Flickinger JC4, Lunsford LD3.

PURPOSE:

Vestibular schwannomas (VS) are increasingly diagnosed in patients with normal hearing because of advances in magnetic resonance imaging. We sought to evaluate whether stereotactic radiosurgery (SRS) performed earlier after diagnosis improved long-term hearing preservation in this population.
METHODS AND MATERIALS:

We queried our quality assessment registry and found the records of 1134 acoustic neuroma patients who underwent SRS during a 15-year period (1997-2011). We identified 88 patients who had VS but normal hearing with no subjective hearing loss at the time of diagnosis. All patients were Gardner-Robertson (GR) class I at the time of SRS. Fifty-seven patients underwent early (≤2 years from diagnosis) SRS and 31 patients underwent late (>2 years after diagnosis) SRS. At a median follow-up time of 75 months, we evaluated patient outcomes.
RESULTS:

Tumor control rates (decreased or stable in size) were similar in the early (95%) and late (90%) treatment groups (P=.73). Patients in the early treatment group retained serviceable (GR class I/II) hearing and normal (GR class I) hearing longer than did patients in the late treatment group (serviceable hearing, P=.006; normal hearing, P<.0001, respectively). At 5 years after SRS, an estimated 88% of the early treatment group retained serviceable hearing and 77% retained normal hearing, compared with 55% with serviceable hearing and 33% with normal hearing in the late treatment group.
CONCLUSIONS:

SRS within 2 years after diagnosis of VS in normal hearing patients resulted in improved retention of all hearing measures compared with later SRS.

[Citiview]

It would be nice to know, in general terms, what the most current thinking is regarding hearing preservation.
Radiation compared to watch and wait compared to surgery
What are the reliable predictors of hearing preservation?
fundal fluid? Nerve root? Etc
ABR? VNG?
Cochlear implants etc.
There's so much info out there.

[ANSydney]

So, the article recommends to act within 2 years for radiosurgery rather that delay. The dilemma would be, what if after 1.5 years of observation, the tumor does not grow. Do you act on a proven non-growing tumor or do you keep observing? Since about two-thirds of tumors do not grow after diagnosis, most people in the observation group will face this dilemma.

[Citiview]

The problem is that there is great disagreement about hearing preservation in general and in regards to radiation. Different doctors have different opinions about it.
So it's difficult to risk everything that you have - complete hearing - on any one study or opinion. Plenty of people here have lost hearing suddenly in surgery and within weeks of radiation.
A bird in hand......

It's different if it's growing, then that's the motivation to treat. That's how I see it, but people should do whatever they want.

That abstract of the paper doesn't tell about the sizes of the tumors. Maybe the complete study contains that info. I was assuming non-growing small tumors with no hearing loss.

[ANSydney]

Here's a link to the complete paper: https://www.researchgate.net/publication/291385676_Early_Radiosurgery_Improves_Hearing_Preservation_in_Vestibular_Schwannoma_Patients_With_Normal_Hearing_at_the_Time_of_Diagnosis

There are limitations in this study. The main one has been identified by the authors: "there were some differences in the pre-SRS PTA and SDS, with PTA being significantly higher and SDS being slightly lower in the late treatment group, which may have biased our results". I might add that the number of patients after 6 years is small and therefore just one patient either way can significantly affect the long term figures. The "treat ≤2 years" group had, at time of diagnosis, a median PTA of 12 dB and the "treat >2 years", at the time of diagnosis, a median PTA of 17 dB. This may not sound like much of a difference, however if we look at it from the point of view of how much reserve is available before hitting the end of GR Class 1 hearing we have 18 dB and 13 dB respectively up our sleeve. The expected difference in Fig. 1 is somewhat expected. If this were true, the difference when considering GR Class I/II would be smaller and this is what we see in Fig. 2. To me, the results reflect the different at-diagnosis PTA levels rather than the time from diagnosis to treatment.

What is lacking is a comparison of hearing loss if conservative management is followed. A paper https://pdfs.semanticscholar.org/2cef/abe8e8eef1ae32cab8bcf3c71dd75f53387c.pdf looks at long-term hearing preservation. This study is more informative since even at 10 years, 94 patients were still observed. The PTA loss at 10 years is about 47%. What's more, it plateaus at about 7 years. This is in keeping with Stangerup's finding that it is very rare to have tumor growth after 5 years from diagnosis.

Radiosurgery however appears to have hearing decline going on progressively. This is not visible in the first paper's Fig. 1 and Fig. 2, but when the numbers involved are considered, we just don't know. There is a paper "Stereotactic radiosurgery for vestibular schwannomas: average 10-year follow-up results focusing on long-term hearing preservation" Watanabe et al 2016. It shows hearing continuously deteriorating following radiosurgery dropping to 49% at 5 years, 24% at 10 years and 12% at 15 years. It just keeps dropping!

It looks like hearing preservation is best for conservative management. If the tumor is not growing, this may be the best approach. However, if treatment is required (tumor growth or significant symptom progression beyond hearing loss), radiosurgery appears to have better outcomes than conventional surgery.

Interesting topic.

[Citiview]

Radiosurgery however appears to have hearing decline going on progressively. This is not visible in the first paper's Fig. 1 and Fig. 2, but when the numbers involved are considered, we just don't know. There is a paper "Stereotactic radiosurgery for vestibular schwannomas: average 10-year follow-up results focusing on long-term hearing preservation" Watanabe et al 2016. It shows hearing continuously deteriorating following radiosurgery dropping to 49% at 5 years, 24% at 10 years and 12% at 15 years. It just keeps dropping!

Thanks ANSydney. I haven't gotten a chance to read these papers, but thanks for the links and the above reference.

I have been told by two neurotologists that there is recent research with findings that radiosurgery degrades hearing. Perhaps the above research is what they are referring to.
Also, here's a link to doctors from Weill Cornell who made the same statement about radiosurgery and hearing.

https://www.anausa.org/sponsors/weill-cornell-medicine

I'm no expert, but when you keep hearing the same info. from doctors over and over again it becomes a pattern and you start to believe it.

[PaulW]

There is a report somewhere comparing watch and wait surgery and gamma knife for hearing preservation.. over 10 years...
It didn't look great for anybody.
Radiation had a slight edge over watch and wait.
Watch and wait and radiation were better than surgery....
But if you were in the lucky percentage from surgery you do keep your hearing long term.
While radiation does have a long term decline many keep some hearing and never become completely deaf.
Radiation, and lack of tumour growth dont explain why hearing is lost. The latest theory is that it is toxins produced by the tumour which add to the hearing loss.

[leapyrtwins]

Not exactly sure what this study is saying - I'm an accountant, not a medical person - but oftentimes by the time someone is diagnosed with an AN, hearing preservation just isn't possible.  And, of course, a lot has to do with the size and location of the AN.

I had decent word recognition and had the retrosigmoid approach in the hopes of preserving my hearing, but it just wasn't possible.  My AN was wrapped around my hearing nerve - something that couldn't be viewed from my MRI - and in order to remove the entire tumor my hearing nerve was "sacrificed".

Not the best case scenario, but not the worst either.  I opted for a Cochlear BAHA (bone-anchored hearing aid) 9 months post-op and life goes on.

Best,

Jan

[ANSydney]

Jan, are you saying that your tumor was growing on the cochlear branch, rather than one of the vestibular branch of your vestibulocochlear nerve?