How long a dog can survive with cancer depends on the disease’s stage (how far advanced it is), its grade (how aggressive the cancer is) and how soon the veterinarian is able to intervene in the disease process, says Dr. Lachowicz.“Depending on how aggressive the cancer is and how aggressively we choose to treat it, some dogs can be cured,” he says. “In other cases, it might not have as good of an outcome. So it really is variable across the board.”