At this time, there is no true cure (100% remission) for brain tumors in dogs (or any species for that matter.) In practice, brain tumors are generally considered to be malignant due to the delicate and poorly regenerative nature of neurons and restriction of the brain to the finite space of the cranium which does not allow tumor growth devoid of collateral damage to brain parenchyma. Therefore, general long-term prognosis for canine brain tumors is poor. Current treatment of brain tumors revolves around four main modalities: surgery, radiation, chemotherapy, and palliative (pain relieving) care. Depending on the type, extent, and location of the cancer, any one or combination of these techniques may be employed. For instance, the first line treatment for meningiomas is surgery but may be coupled with chemotherapy in an attempt to improve survival time. Intracranial tumors (such as glioblastoma) more commonly rely on radiation therapy as surgical access to the tumor may be prohibitively dangerous.  Palliative care tends to include corticosteroids to help reduce swelling and edema around tumors as well as anti-convulsant medications to control seizures.
While brain tumors in cats remain fairly uncommon, it is an issue that occurs, and that can sometimes be treated effectively. A tumor is defined as an abnormal growth of cells, and may be classified as primary or secondary. A primary brain tumor originates from cells normally found within the brain and its membranes. A secondary brain tumor, on the other hand, is one that has metastasized to the brain from a primary tumor elsewhere in the body, or that is affecting the brain by extending into brain tissue from an adjacent non-nervous system tissue, such as bone. A tumor may be either malignant (cancerous), or benign .
Changes in general behavior is another indicator of a tumor. Brain tumors may cause an overall reversal in behavior, according to , with typically gentle dogs acting aggressively or aggressive dogs becoming extremely docile. A brain tumor can cause unusual behavior, such as refusal to eat, extreme apathy to the dog's surroundings, or a loss of learned habits like not using the bathroom in the house. Dogs may become disinterested in favorite activities, such as playing or exercising. In the case of a pain-causing tumor, a normally placid dog could undergo a change in temperament and become abnormally hostile to regular human interaction.