I am so sorry. Losing a best friend is just so hard, isn't it? 

Please don't beat yourself up.  It's not fair to torture yourself over what you might have missed because you clearly did all you could.  He was seeing an oncologist who had just examined him thoroughly, and who would have noted and discussed with you any obvious signs of 'ordinary' disease if he'd found them.  He'd seen him quite recently and had been given the all-clear.  How should you have been able to see what the vet did not?

However, I do know what it's like to have a dog collapse in front of you and die despite the vet's best efforts, and in the end not know why.  In Jack's case he was seeing a vet regularly to try to find out why he wasn't right, but we had not diagnosis until he died, then they said it was embolisms.  And yes, I did blame myself for not doing more, and went into an intense period of grief and depression, but looking back, that wasn't justified, as I doubt it's justified for you.  Remember, saving him from this event might have meant a protracted illness and disability with the same result a little further down the line.  Jack lived for three more days - horrible days, with no quality of life in them - while we tried to save him.

Try to look at it this way: you bought Spirit some good quality time and you loved him deeply and unreservedly, which he undoubtedly knew with absolute certainty.  And when he had to leave you, he did so quickly and without long-drawn-out suffering.  The suffering part (the cancer) was behind him and in his mind, forgotten.  All he knew was that he was with his beloved people, and loving life till the last possible moment.

Sending you some virtual hugs and sympathy from someone who has been through something very similar.    I'm still very sad about Jack four years later, but I can see now that his time had simply come, and there was nothing anyone could have done.

I'm so sorry for your loss.  I will just echo what Jay and Michelle said.  I know it's easier said than done, but don't beat yourself up.  You did everything in your power to give Spirit quality of life and I would say you did that well.  

I'm so sorry to hear of Spirit's passing.  You did the best you could for your boy.  Unfortunately, cancer does not play fair. There's no way you could've known if the professionals did not.  Spirit knows his family loved him.  Sending condolences to your family and Mia.

What a handsome boy!! I am so very sorry for your loss--cancer sucks--you did all you could do for him. Please know that we are keeping you in our thoughts and prayers.

Joan and Lily

I am saddened to hear of your loss and truely understand your pain, saddness and anger. Do not question yourself. How could you miss something that your vet did not even see? My 7 year old Lab is 1 week post of amputation for Hemangiosarcoma of her front let. I was lucky with her. I lost my 14 year old kitty with it last year and the only sign was her staring at me and weight loss which went undected for a while due to her long hair. Remember animals are masters of camoulflage...it's the way they survive.

As tragic and dramatic as it was, in time you grow to know that Spirit's sudden passing was much more dignified than the lingering ones that we sometimes subject our baby's to due to our unwillingness to let them go. Please know you provided a responsible and loving for your sweet Spirit and now she is even more so...a wonderful sweet Spirit!

Wishing you healing and peace.

Mic