My dog has bone cancer (but next month it'll be a year since her diagnosis!), and she was due for her rabies shot 2 months ago. The vet and oncologist didn't think it was a good idea to give her the shot due to her immune system, and they do say vaccinations are for healthy pets. There's no way of knowing if she still has cancer, bone cancer is pretty aggressive (she's made it as far as she had due to amputating her leg and doing 5 chemo treatments). Some live for 1 year, with 20% living 2 years and some are lucky to go past that. I've read that the shot can actually make things worse for a dog with cancer. I'm just not sure is it allowed if a dog is sick to not get the vacc? I was going to ask to have a titer done to see if it's still in her system too. She's almost 8 y/o so she's had many rabies shots throughout her life...I know I've read it actually stays longer in their system than what they say.