Hello, Raja ~
I offer you my experience in the hope that it may assist you in making a treatment decision.
I was diagnosed with a large AN (4.5 cm) that was pressing hard on my brain stem although my symptoms were not excessive. Surgery was indicated, as quickly as possible. However, I was concerned about post-op complications, primarily facial nerve impairment. The prominent neurosurgeon I consulted (30 years of AN removal experience) presented me with a plan to 'de-bulk' the tumor, that is, peel away layers (a very tedious, 9-hour process) that would render the remaining tumor much thinner, a bit smaller and very susceptible to the effects of the radiation he planned as 'step 2' in my treatment. He chose FSR to minimize tissue damage and lessen the probability of nerve damage. After a 90-day 'rest period' (the doctors term) I underwent 26 FSR treatments (with no negative effects). They were co-supervised by my neurosurgeon and a brilliant young oncology physician who 'mapped' the radiation pattern for maximum effect on the tumor and minimum affect on me.
I underwent the de-bulking surgery and had almost no complications, specifically, no facial nerve involvement. The FSR was uneventful and later MRI scans showed tumor necrosis and the beginnings of shrinkage. My symptoms never returned and with some work on my part, my balance was restored to approximately 80% of normal (my estimate). Unfortunately, the hearing in the AN-affected ear was permanently lost but I've adapted quite well. All this occurred over six years ago, when I was a lad of 63. Today, I'm doing great and enjoying life.
Based on my experience, my suggestion to you, following your two surgeries, is to undergo radiation of the remaining tumor. I found the FSR to be tedious (26 separate sessions over 5 weeks) yet very effective. However, the kind of radiation to use is a choice to be made by you in consult with your doctor(s). I wish you well as you approach this decision.
Jim