Bone Cancer In Dogs

I got the bad news this morning that my Labrador has bone cancer in his rear leg. It came from nowhere. Just a little bump 3 months ago and today, it’s this big whelp on his rear knee. The xrays show massive erosion in the bone. I say cancer, but the vet won’t know for sure until the biopsy returns on Monday. He’s pretty sure it’s cancer, though.

I have a decision to make. If I had all the money in the world, I’d nurse him along to a merry old age. But I don’t, so I cannot. I can have his leg amputated and hope the cancer didn’t spread. And in that, could hope he lives a reasonably healthy existence, otherwise, or I could have him put to sleep. It’s really a tough call for me. I could be throwing money at the problem when the dog would be better off just having been put down.

I hate to think dollars would control this decision, but it just may very well.

Thanks.
Forgot to mention his age and I know how relevant that is.

10 years. 100 lbs.

Alright some of you have already answered my question about my dog Roseanna. it was a hip dysplasia question. Well She does have hip dysplasia, but she has bone cancer in the left leg she cant bend or even use. but good news is, is it hasnt moved to her chest which im thankful for. We have an appointment for surgery on the 2nd of February, to get that left leg removed. and i was just wondering what the chance of her not making it through the surgery. Roseanna is 6 almost 7. she is a chocolate lab. Any thing will help, even Just comment if your not sure, or if your sure. Please i really want to know. Roseanna is an amazing dog. i love her to death and i just want to prepare my self.
oh im doing the surgery, trust me its best for roseanna and it needs to be done before it spreads. i just dont think my heart could take it if i loose her.