I saw the attached exchange on the Cyberknife support group board and thought it might be of interest on this board as the poster asks some very good questions about radiosurgery. It also highlights how important it is to make the effort to get opinions from experienced docs of both treatment options. It is very true that virtually every AN patient is diagnosed by an ENT and immediately referred to a surgeon. I also believe that few surgeons provide new patients with a fair representation of the radiosurgery option either a) because they truly do not understand it or b) it's not in their best interest ( financially) to suggest it. Taking control of your healthcare choices and not accepting any one doctors opinion is critical in this process. There are docs with bias to their specialty and you need to determine which option gives you the best option. Whichever choice you make, sort the fact from the fiction. The exchange below certainly provides an illustration
Mark
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PATIENT
I am 37 and have a recently diagnosed right-side 4mm x 8mm AN. I noticed dizziness and then fullness in my ear, followed by tinnitus - otherwise very few symptoms to date. I have met with a Gamma Knife MD and a otolaryngologist to get opinions this week. I heard some troubling info and want to run it by the Dr's on this site:
The Gamma Knife MD said the 1 mm "error rate" of the CyberKnife could make an enormous difference with ANs and that the CyberKnife would be better for a non-brain tumor (the Gamma Knife was the "gold standard" for ANs). He also said that if I want to have children I might not want radiation.
I was told by the Oto MD that radiation (CK or GK) on a patient my age should be considered "unethical" and could result in 1) high AN recurrence rates, 2) fusing of my tumor to nerve tissue making almost unavoidable future surgeries complex 3) a likelihood of radiation causing future cancerous brain tumors (sarcomas) and 4) possible "explosion" in teh growth of the tumor from the radiation.
This was from a reputable doctors in a major metropolitan area. Are these facts true? I was extremely shaken following the appts and feel very lost. I need some objective facts.
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DOCTOR"S RESPONSE
Quite a lot of nonsense.
Dr. Change has previoiusly reviewed the accuracy of CyberKnife and GammaKnife. Suffice it to say, there is general agreement, based on very good data, that the accuracy of the CyberKnife is about 0.9 mm from start to finish of the treatment process. The accuracy of the Gamma Knife is a little harder to determine. The mechanical accuracy of the beam pointing is about 0.5 mm. However, there are several other sources of inaccuracy, including the inherent lesser accuracy of MRI compared to CT, frame torsion effects, and manual or automatic positioning. It is reasonable to consider the accuracy to be about 1-2 mm. For all intents and purposes, it is probably best to consider the systems equally accurate. THe only otehr possible advantage of one system over the other is that there is a possibility that fractionated treatment, such as is possible on the CK, may be better for preserving hearing. This subject remains ccontroversial and unproven. We hope soon to start a randomized trial.
The otolaryngologist was employing classic scare techniques. THese guys make me nuts. I don't mind opposing opinions, but scaring patients like this with falsehoods IS unethical in my opinion. I don't know of another physician, regardless of specialty, who considers it unethical to treat AN's with radiosurgery, although some disagree as to whether it is best. Recurrence rates have always been reported in the 2-5% range, equally as good as surgery and without the immediate complications. It is true that surgery following radiosurgery would be more difficult, but our surgeons have done it successfully. With the usual success rate reported to be 98%, why would you want to accept the immediate complications to avoid a 2% chance that your surgeon might have to work harder at your operation in the future? As for future malignancies and explosive growth, these are the goonies under the bed at night. There have been isolated cases of rapid tumor growth following any kind of treatment. There have been rare malignant transformations of the AN's following any kind of treatment (including surgery). Sarcomas and so forth following radiosurgery appear to be extremely rare, even more than after external beam radiation. I can find only one reported case in all the world literature. Compare that with a 13% risk of CSF leak through the scalp wound (with 2.5% requiring re-operation), 9% meningitis, only 80% preservation of facial nerve, 3% permanent epilepsy, and 7% leakage of CSF through the nose (requiring re-operation in 2.5%) as reported in a large series from 2001, therefore with modern techniques.
Clinton A. Medbery, III, M.D.
St. Anthony Hospital Cyberknife Center
Southwest Radiation Oncology
1011 N. Dewey Ave.
Oklahoma City, OK 73102
