Hi, Laleh, and welcome to the forum.
Whatever type symptoms you have at the time of CK, there is a chance they will be exacerbated by the treatment (this is according to esteemed Stanford-based doctor, Dr. Steven Chang). You may not have any symptoms worsen, but it's possible. If they do worsen, it's most likely going to be transitory, lasting up to several months but possibly only a day.
If you have vertigo prior to CK, it could possibly worsen after treatment. If you don't have vertigo prior to CK (and even if you once had vertigo but no longer do at the time of treatment), it is highly unlikely that you will have vertigo after treatment. So, to summarize, it's only the
pre-existing symptoms that could possibly worsen temporarily post-CK.
The worsening of symptoms (if they occur) is due to the cranial nerves becoming irritated or damaged by the radiation itself or by the tumor swelling in reaction to the radiation and creating irritating inflammatory compounds. Once the swelling goes down, dizziness and vertigo should decrease. And if the symptoms are due to damage to the vestibular nerve, your brain will eventually compensate and learn how to ignore the aberrant balance signals the damaged side is sending.
Now for my story, in brief, to illustrate one person's experience:
I had severe vertigo, oscillopsia and disequilibrium 9-1/2 years ago at the onset of AN symptoms. Due to years of misdiagnosis, I only received CK 19 months ago. At the time of treatment, I hadn't had vertigo or oscillopsia in over 8 years. Immediately after CK, my disequilibrium worsened by, subjectively, about 15 to 20% and stayed like that for six months. But I had no return of vertigo or oscillopsia. My MRI at the 5-month mark showed my tumor had swelled in volume 33%. At the six-month mark post-CK, my balance began to improve dramatically. Now I feel my balance is actually around 60 to 65% better than it was right before getting CK! According to Dr. Chang, about 25% of patients experience improving balance after treatment. My 11-month MRI showed my tumor had shrunk 59% in volume from its peak size and was smaller than it was before treatment. So there is some validity to the belief that a shrinking tumor could possibly cause less severity of symptoms. This is thought to be due to the fact that a shrinking tumor puts less pressure on the affected cranial nerves.
Please note that having surgery, in lieu of radiotherapy, can cause just as bad of an increase in balance problems as CK or GK. Scraping a tumor off a cranial nerve can damage or irritate the nerve as much or more than radiation. In fact, in many cases, radiotherapy is the only treatment that holds the potential for preserving hearing; this is because, for medium- and large-size tumors, surgery is often more traumatic to the hearing nerve. In your case, however, since your tumor is small, surgery may not be any riskier than CK vis-a-vis your hearing preservation. Bottom line: CK and GK are definitely not contra-indicated for patients with balance symptoms. But you might notice an increase in those symptoms, though they would most likely be transient in duration. Nobody can guarantee results, though, and there are serious risks with any type of treatment for an AN. See my post comparing the benefits and risks of surgery vs CK vs GK here:
http://anausa.org/forum/index.php?topic=6670.0I hope that helps. Good luck!!
Best wishes,
TW