There are 3 basic options for the treatment of tumours:
Option 1 – Medication alone
There are very few chemotherapy options for brain tumours in dogs and cats because the brain is a very protected site and most drugs cannot penetrate it. However, treatment may help to reduce some of the signs seen in a patient with a brain tumour. A combination of anti-inflammatory medication (corticosteroids) to reduce the swelling and pressure caused by the tumour, and drugs to reduce the severity and frequency of seizures can be prescribed. In some cases this may relieve a lot of the symptoms and make the animal feel a lot better. However, animals on this combination of drugs are often very thirsty and hungry and may need to go to the toilet more often – occasionally this can cause problems with wetting in the house. The drugs used to control seizures may initially make your pet more sleepy, but most dogs get used to the drugs after a couple of weeks. This approach does not cost much and there is little risk of making your pet worse, however, in some cases this may only provide relief for a couple of months.
Option 2 – Medication and radiation therapy
While many brain tumours in dogs and cats are relatively benign and amenable to surgery, some are deep seated and therefore pose significant surgical risks. Radiation therapy can result in dramatic and rapid improvement of signs. The benefits of this treatment far outweigh the risks in most pets. It is not common for animals to suffer side-effects from the radiation treatment but these might include; occasional nausea, mouth ulcers, ear infection or, rarely, blindness. Most of the side-effects of radiation can be controlled with additional medication. The advantage of using radiation treatment, in addition to medication, is that it can provide a longer period of good quality of life than with medication alone. Unfortunately, radiation rarely completely destroys the tumour and average remission times are 8 to 14 months before the tumour recurs.
Option 3 – Medication, radiation therapy and surgery
The ultimate goal of cancer surgery is to remove the tumour completely. Unfortunately, this is rarely possible with brain tumours and there are nearly always tumour cells left behind which cause the tumour to regrow. However, by removing as much of the tumour as possible during surgery, the remaining cells may become more ‘sensitive’ to radiation. The polytherapy approach (combination of medication, surgery and radiation) is the mainstay of treatment for most brain tumours in man. The aim of treatment is to remove the bulk of the tumour by surgery to give other therapies a better chance of success.
Surgery also allows the vet to obtain a sample of the mass and identify its nature, which may make it easier to give a more accurate prediction of how well the patient is likely to do. Not all brain tumours in dogs and cats can be removed surgically, practicality depends on their position within in the brain. Tumours that are on the brain surface are more likely to be amenable to surgery. To reach a tumour deep within the brain, the surgeon would have to cut through a large area of healthy brain tissue and this could have devastating effects for the recovery of the patient.
Surgery is the most invasive and costly option. Although many dogs recover well and without complication, brain surgery can occasionally cause irreversible damage to the brain. Some owners report that their pet’s personality and behaviour has changed after surgery. Brain surgery does carry a risk, particularly if the patient has other health problems as a lengthy anaesthetic is needed. Occasionally the patient may not recover from the surgery. The benefits of this option are that it potentially offers the longest period of quality of life for your pet.