The idea of treating your beloved pet with radiation therapy can sound daunting. However, new studies and findings have discovered that using radiation therapy for treating cancer in our canine and feline companions can actually make a significant difference in overall survival and quality of life. Typically, radiation therapy is used in dogs and cats after surgery, or in conjunction with chemotherapy, immunotherapy, and targeted therapies. In certain tumors, the goal of using radiation therapy is to eliminate any cancer cells that may remain following surgery. However, depending on the type of cancer and if it is localized to a certain area, Dr. Ratterree, a veterinary radiation oncologist, may recommend the use of radiation therapy alone. Radiation therapy can even be used to ease the pain of certain cancers in pets such as bone tumors (osteosarcoma). This form of therapy is called palliative (or coarse fractionated) radiation therapy and it can be delivered any location of cancer from 2 – 6 doses with minimal to no acute side effects to normal tissue.
In veterinary medicine, radiation therapy is most commonly delivered with a sophisticated machine called a linear accelerator (external beam radiation). This machine delivers ionizing radiation to the malignant cells to inhibit their ability to divide and grow. Both normal and cancer cells are affected, but the radiation treatment is designed to maximize tumor effect and minimize normal cell effect. Definitive radiation therapy is given in a series of treatments (called fractions) administered on consecutive weekdays. This schedule helps protect normal, healthy tissue by spreading out the total dose of radiation over a period of time. The total dose used and the number of fractions in which the total dose is administered depends on many factors and may be different for individual patients. These factors include the size and location of the cancer, the general health of your pet, and the type of cancer present. On the first day of radiation therapy, Dr. Ratterree and the radiation therapists work together to ensure that your pet’s treatment is delivered precisely as planned. Typically, treatments are done on weekdays (unless an emergency), patients are allowed to go home the same day, and the average actual treatment time takes approximately 15 – 30 minutes.
Radiation therapy can have side effects in animals just as it does on human patients. The side effects of radiation usually appear halfway through the prescribed dose and can last from 1 – 3 weeks, depending on the site that is being treated. There are many topical and oral medications that Dr. Ratterree can prescribe to help minimize or prevent any impact that radiation therapy has on your pet’s quality of life. As expected, hair loss at the irradiated site is most common. Other side effects are very dependent on the particular site that is being treated. Your CancerVets oncologist can discuss the potential side effects of radiation therapy that may be expected in your pet at the initial consultation or any time during the course of therapy. We are here to answer any questions that you may have in regards to your pet’s care – just ask!