I'm so sorry to hear about your pup's diagnosis. I don't have experience with prostrate cancer in a dog, but we lost our Ivy several years ago to bladder cancer. She was diagnosed after a biopsy that was taken when she didn't respond to treatment for what we thought was a bladder infection.
Ivy was also 10 at the time. My vet offered me several options: chemo and radiation were included, but I know how tough they can be on dogs, which he confirmed, so we opted to treat her with medication instead, which I gave her daily. It did make her more comfortable, and other than having to go out more often, she was quite herself for more than six months.
I know that doesn't seem like a long time, but it was preferable to us to have her happy and normal for six months than to have her undergo treatments that would make her sicker to keep her for a bit longer. When it became clear that she was uncomfortable, we said goodbye to her. It is never easy to make this decision, and each pet owner has to decide what is right for them and their beloved pet. Be sure to ask your vet to describe all the available options to you so you can make an informed decision.
If we can help you through this difficult journey, we're here. Sending you hugs and special pats to your boy.
