Radiation treatment options
Introductory comments about acoustic neuroma treatments
The options open to AN patients are basically:
Before deciding on the type of treatment you want, ensure that you know all your options. We recommend that you start with the treatment options page. This page is for patients who are contemplating radiation. Different pages explore surgical and wait & watch options. You are strongly advised to read them all before making any decision.
Reasons to choose radiation rather than surgery
There are many good reasons for choosing radio treatment, however, you must recognize that, whilst the AN will be killed and stop growing and in many cases will shrink significantly, it will still be there; albeit in residual form. So, for those people who insist that they "want the thing out of their heads" this is not an option.
However, for the majority of people who are happy if the AN is prevented from doing any further damage and who wish to avoid the negatives of micro-surgery, there are two main radio treatment choices plus a number of variations.
Typical advantages are :
Introductory comments about radiation treatments
Radio treatments fall into two broad categories by treatment method and three more categories by generic machine used. There are also a number of sub-divisions of each, so making an informed choice can be quite a time consuming affair.
You might have noticed that we have carefully used the term "Radio-treatment" throughout most of this site. However, elsewhere, you will more usually come across the terms "radio-surgery" and "radio-therapy". We have tried to avoid these terms, as there is a degree of controversy about which is correct in what situation. If you wish to learn more about this issue, click here.
The Treatment Methods
The two methods are single session and fractionated or multi-session. The difference as you may guess, is that in the first, the treatment is given in one treatment session, whilst in the second, the total treatment is divided into a number of "fractions" and given over a period of days, weeks or even months.
There are three fundamental machines (again, with a number of sub types!), which are used for Radio-treatment. They are:
Radio-treatments -- Further Detail
Gamma Knife is sometimes said to be "like a big Mac" - that is, the same wherever you get it. Please beware, as this isn't true. Just as with other AN treatments there are variations in the machine, in the software used for planning and in the experience and preferences of the treatment team. So, if GK is your choice, don't just assume that the local GK centre (if you have one) will match results obtained by the best, they may not.
Our advice is that the two factors that matter to the average patient are the historic outcomes achieved by the particular centre and the dosage used. Other issues such as software standard used, planning protocols adopted and so on, whilst of academic and professional interest are beyond the average patient to assess. And, at the end of the day, if Centre "A" produces excellent results with (say) the 2001 release of software those results are more important than the fact that Centre "B" has the 2004 release software but can't provide its statistics.
The one thing that can be understood by patients however, is "total dose". It is a general rule of thumb that a lower total dose results in (statistically) lower side effects. Many people therefore conclude that if the control rates of two GK centres are similar, then the one with the lowest total dose will be the one with the lowest side effects. There are however two things to beware of when using this logic:
Fractionated Stereotactic Radio-Treatments (FSR)
FSR divides into two basic types:
Hypo-fractionation has several advantages over simple FSR. These are:
At an even lower level of detail, the issue of time between fractions is debated. Radiological theory says that as long as there are 18 hours between fractions, the healthy tissue can recover and any longer gap offers no advantage. However experience now suggest that the theory is inadequate in some way.
Dr Gil Lederman's pioneering FSR treatments were originally offered on the basis of fractions given on a daily basis or with a greater gap if it suited the patient's circumstances better. For example, some of his patients opted for one treatment a week to suit their working patterns. An analysis of the outcome for the first 200 patients treated revealed that those who had 48 hours or more between fractions had far better hearing outcomes than those who were treated on a daily basis. Now Dr Lederman treats everyone on the basis that they should have at least 48 hours between fractions. Whist Dr Lederman has demonstrated by far the best hearing preservation results of any AN treatment in the world, many experts do not accept that it is the bigger gap between fractions which gives this advantage.
Cyber-knife treatments all fall into the "Hypo-Fractionated" category. However, as alluded to elsewhere, in other respects the treatment is more like GK. This is because the robot arm moves the Linac to a particular position; gives a dose whilst stationary; moves to a new position, gives a second dose and so on.
Proponents of Cyber-knife will claim that this is an advantage, others quote it as a drawback. Once again, our advice is to ignore this debate and look at the results achieved at the centre you are considering. If they appear to be good, then that is the important fact.
Proton Beam (PB)
Whilst offering the theoretical advantages outlined above, experience with this treatment is so limited that we are unable to offer any further detailed information. Should any reader either have such information or have personal experience of PB treatment for their own AN, the authors would be delighted to hear from them in order to update this section in due course.
The Accuracy Debate
Sometimes, treatment centres will claim that their treatment machine (Gamma Knife, Linac, Cyber-Knife) is "more accurate" than the others. We have seen "evidence" that shows each of these three common machines to be the most accurate!
It is our opinion that such a debate is meaningless. Why is this? Well, we also see evidence of excellent results from experts using each of the machines (and less good results from the less expert) and at the end of the day, it is the results which count. Once again our advice is find the centre/treatment provider whose results look best for you and not to worry too much about how that is achieved.
After all, if you are buying a painting, you don't worry that the artist may have chosen the wrong sort of brush; you judge what is on the canvas! (And I can't produce a Leonardo, even if you give me the very brushes used to paint the Mona Lisa!)
The Great Terminology Debate
As mentioned in the introduction, there is a great debate over the correct name for Radio-Treatment. Whilst to we patients this is of less importance than "will it work for me", curiosity makes most people want to learn a little about it. To do this, we need a short medical history lesson.
Over 50 years ago now, radio-therapy was used for non-invasive treatment for many conditions. This involved irradiating a lot of the body in addition to whatever was being treated. For some conditions, this was actually beneficial, for many however, it caused more problems than it cured.
In the 1950's a Swedish Surgeon turned his considerable intellect to finding a way to use Radiation in a focussed and controlled manner with surgical precision to treat lesions in the same way as a knife, but without the need to cut the patient open. This was Dr Leksell and his machine became the prototype Gamma Knife. He coined the term "Radio-Surgery" to describe the treatments he gave using it and to differentiate this treatment from the crude radio-therapy treatments offered up to that date.
More recently, with the invention of the Linac and its adoption as a medical instrument, people have offered "radio-surgery" using these machines rather than GK machines. The GK machine makers (and by extension, the Doctors who use such machines) have tried to claim at various times that Radio-surgery is:
As patients we consider this to be an attempt to retain a competitive advantage for selling the GK machine, rather than a substantive issue. Our view is that if there is precision, it is reasonable to call it "radio-surgery", but at the end of the day, we don't mind what you call it as long as it works!
Other situations that involve radiation
Short term and long term outcomes
www.anausa.org The Acoustic Neuroma Association (USA). There is a lot of useful information on this site and a guest book as well as a very active mailing list for patients.
www.ANSeattle.org The Seattle (WA) Acoustic Neuroma Group - SANG.
www.anarchive.org The AN Patient Archive site, full of information and patients' stories.
1 Facial paresis is the medical term for facial paralysis, usually partial, often temporary, which results in a lopsided face and/or difficulty in closing the eye.
2 Meningitis is an infection of the fluid of a person's spinal cord and the fluid that surrounds the brain. It can be fatal, especially in the young. Go to http://www.meningitis.org/ or http://www.musa.org/ for more information.
3 Tinnitus is a constant buzzing or ringing in the ear, often experienced by AN patients (and many non-AN patients for various reasons).
4 Dry eye is a condition where the surface of the eye is insufficiently lubricated with tears. Often the result of the eyelid failing to close completely.
5 Hydrocephalus is pressure on the brain caused by a problem with the flow of cerebrospinal fluid (CSF). This can be due to blockage of the ventricles or to a thickening of the fluid.