Well, those were our doctors words, I remain cautiously optimistic. He has also said he "has no reason to believe the tumor will return". I think he is basing this on the degree of how complete my wife's resection was, the radiation/chemo treatments she has had so far, and the details of her pathology, which was AAIII, malignant but less aggressive than GBM. Or, it could be that he is just projecting a positive take on my wife's chances. Just like every patients story is different, I think every doctor has their own way of interpreting medicine and their own way of communicating to the caregivers and patients what they believe. Your doctor is just being upfront with you about what he/she believes, I think that is to be respected, but any outcome is possible. I am glad your son has not shown any signs of re-growth. It sounds like he is responding to his treatment so far. My wife has a year more of Temodar (chemo) to go, but it's working for her to date. I believe that youth is a powerful weapon against this cancer. All the best to you and your son.