Treating Osteosarcoma in Dogs with Radiotherapy

Osteosarcoma in dogs is a form of bone cancer. Although it is a rare form of tumor for a dog to acquire, it is the most common bone cancer seen in dogs. A popular treatment used for this condition is radiotherapy.

Osteosarcoma in Dogs Explained

Osteosarcoma begins deep within a dog bones and becomes more painful for a dog as time and the disease progress. Essentially, a dog’s bone is destroyed from the inside out as the tumor grows and the bone affected is replaced by tumors. The cause of osteosarcoma is not known. Osteosarcoma can occur in any breed of dog, but is seen most often in middle-aged or older male dogs of large breeds that have been castrated. Symptoms of osteosarcoma include lameness in the limb affected and a mass or swelling in the affected limb. If the cancer is in the dog’s jaw, he may have difficulties eating. A tumor in the hip can cause a dog to have trouble passing stool. Osteosarcoma can also cause the affected limb to easily break with the slightest injury.

Treating Osteosarcoma in Dogs with Radiotherapy

Osteosarcoma treatment needs to be aggressive as this type of cancer is strong and can easily spread to other bones in a dog’s body, the lungs and even lymph nodes. The goals of treatment are to help manage a dog’s pain and mobility difficulties, and to rid the dog of the cancer if possible. Radiotherapy uses radiation on affected tissues so the cancerous cells cannot multiply and spread. The trick to radiotherapy is killing the cancer cells without killing too many of the good, healthy cells in a dog.

Radiotherapy is often a popular choice for dogs because surgery is often not a treatment option when it comes to osteosarcomas. Radiotherapy is also used because it does not have as many of the adverse side effects that humans may experience while undergoing this type of treatment. The most common side effects of radiotherapy for a dog are hair loss and irritation of the skin that may resemble a sun burn. Radiotherapy typically lasts about 5 weeks with a dog receiving a couple treatments per week.

There are two types of radiotherapy treatments: teletherapy and brachytherapy. Teletherapy, also called external beam therapy, is done with a special machine that is a cobalt unit, an electrical machine, a specialized x-ray machine or a megavoltage machine/linear accelerator. External beam therapy is the most popular type of radiotherapy treatment for dogs.

Brachytherapy, or interstistial therapy, is when small devices are implanted into a dog’s skin. These anodes give off small amounts of radiation at a time to kill a tumor. If a dog is undergoing this type of radiotherapy, he has to be kept in a separate room.

The prognosis for a dog with an osteosarcoma depends on his age, the size of the tumor and the spread of the disease. It is best to seek early treatment for this condition, which may include the use of radiotherapy.