Hi, Frank:
Unless there are very special circumstances in your case that indicate otherwise, radiation most certainly has at least as good potential for preserving your hearing as microsurgery, and possibly better. CK and GK are both generally excellent options for AN patients with a small tumor such as yours.
Ask your doctor to perform an ABR (auditory brainstem response) test. An ABR test gauges the functional integrity of your hearing nerve at five points by measuring the amplitude of signals sent along it. (It's a fast and painless procedure.) Dr. Derald E. Brackmann (famed neurosurgeon at House Ear Institute) relies in part on the ABR test to predict the likelihood that microsurgery will cause total loss of hearing on the AN side. The idea is that if your hearing nerve's function is hanging on by a thread (low amplitude measurements at most or all of the five measured points), your hearing is not likely to survive the trauma of microsurgery.
The reason why fractionated radiotherapy (such as CyberKnife, or CK) is thought to offer a slightly better chance of preserving hearing than non-fractionated radiosurgery (such as GammaKnife, or GK) is that the tumor is more sensitive to the radiation than the healthy nerve tissue in the hearing nerve. The lower dose, applied three or more times, gives the hearing nerve a chance to rebound, whereas the tumor rebounds slower and therefore doesn't have a chance to recover before the next dose of radiation zaps it again.
It's important to realize that "hearing preservation" is not inferred to be total preservation of hearing, by AN specialists. It merely means the "preservation of some serviceable hearing." You could lose 80% of your hearing and still be regarded as having had your hearing preserved on the AN side! Also, when doctors talk about their success rate with preventing hearing loss in their patients, they usually mean that those patients who didn't lose any hearing remained in the same hearing Class. A hearing Class is a range of hearing within which your average hearing ability across all frequencies falls. So, if your average hearing ability worsens, say, 15%, it may nevertheless still fall within the same range of hearing or Class. In such a case, your doctor may regard your case as one in which hearing function did not degrade after treatment. Keep these points in mind when talking with your doctors, as they will not likely elaborate and you might otherwise see a rosier picture than what they mean to give in their prognosis.
For your size tumor, generally speaking, all three options (W&W, microsurgery and radiation) are tenable. Medium-size tumors (i.e., ones larger than yours) in concert with poor ABR test results often present more difficulty in preserving hearing with microsurgery; in that case, the non-invasive radiosurgery (one dose) and radiotherapy (multiple, fractionated doses) options generally improve your chances of preserving your hearing. Tumors over 3 cm in size along the oblique transverse axis (more or less horizontal axis) of measurement normally require microsurgery; radiation is usually ruled out for such large tumors.
But you're in the "small AN" category. All three options are open to you. Take your time, do your research, let it digest and then see what feels right to you. Inform yourself and then trust your gut, and you'll come out fine.
Best wishes,
TW
