Senior dog tumor, high ALP, lethargy, joint pain. Is it cancer?
I suggest your vet take a fine needle aspirate (FNA) biopsy of the tumor to find out what kind of a tumor this is. He would be taking a little bit of tissue from the tumor painlessly with a fine needle which helps determine what kind of a tumor this is.
As for the elevated Alkaline Phosphatase level: this could be a sign of liver disease/gall bladder disease or bone cancer in your dog. However, if your dog had bone cancer, it would likely have some bone pain somewhere. 51% of dogs over 8 years have a high ALP. Because there are so many causes of a high ALP, many of which are benign (harmless) processes, determining the cause of an individual dog's high ALP is difficult.
Your vet may want to refer you to a veterinary internal specialist.
Joint pain can also be caused by arthritis, and the lethargy could be caused by pain or disease
Updated on September 23rd, 2025