Maximizing tumor effect is one reason that radiation treatments are given as a series of small doses rather than one large dose. Radiation therapy is used to treat localized disease. It can be used in the management of cancers which cannot be treated successfully by surgery or chemotherapy alone. Typically, it is employed following surgery when there are tumor cells remaining after excision, either because of the nature of tumor growth,or because a complete surgical removal of would involve a very extensive procedure involving vital structures. In some instances, radiation therapy may be employed before surgery or chemotherapy in an attempt to shrink down a tumor to a more manageable size.
Radiation therapy can offer, in some instances, permanent control of a tumor.
Even when a cure is not possible, radiation therapy can still bring some relief. Shrinking a large tumor with radiation therapy may improve a pet's quality of life by reducing pressure, bleeding, or pain. This is called palliative treatment. There are some risks involved with any type of cancer treatment. In addition to cancer cells, some normal cells will also be killed by the radiation.