How To Treat Rhabdoid Tumours Of The Brain In Childrens?

My grandson has a rabdoid tumour of the brain. He has been in remssion for 5 years. He is 10 years old. during his regular MRI they found a thickening in the upper jaw bone. They say it might be dental but it could be a tumor. Emergency surgery is scheduled for tommorrow. How likely is it another type of cancer caused by the chemo and stem cell transplate he had before.