So sorry it wasn't better news furbaby. 
Our girl is almost 13 and a half.
We know she has osteosarcoma in her hind leg and it's incurable. Prognosis even with amputation, radiation and chemo is only a few months. Tomorrow's xray is to check for lung mets, but she's been coughing this week, so we think we know what the answer will be. Lung mets are already there at diagnosis in over 90% of cases of osteosarcoma, but we want to know how big/bad they are to help us make quality of life choices for her, iyswim.
They don't want to risk a general anaesthetic this time, so they're just going to give her a little sedation and I'm going to wait at the surgery for her while they do it. At least it's at 9.00 am, so I won't have to wait long to know.
She's on tramadol and anti-inflammatories and they seem to be keeping her comfortable, but she gets restless, whiny and pacey about an hour before her next dose is due.
The problem is, she is still eating well, asking to go out, bringing us her toys and coming for cuddles. She's slowed a lot and is very different than she was even back in the Autumn, but she's still her and just not the picture of a terminally ill dog that you would expect. I have never had this before, she is our sixth dog and we've always known the right time with all our others. This time it's a case of trying to choose a time that is right, but not leave it too late so that she is suffering, but the vet said she is a strong and stoic dog and could well be masking her suffering in an attempt to please us - which makes it even harder. 
We are into three weeks of this now and the longer it goes on, the harder it gets. I've spent such a lot of time crying and poor old dh had to walk out of his office today because he felt like he was going to cry.
I hope the meds and diet work and your boy is more comfortable.