Low-dose radiation therapy in dogs with elbow osteoarthritis

About the trial

Osteoarthritis (OA), degeneration of the joint cartilage, causes pain in people and animals. It is one of the leading causes of reduced mobility in both species. Numerous treatment options are available for the treatment of OA-associated pain, yet few of these treatments have been researched sufficiently. At this point, we simply don’t know which treatment works best, which is why we are performing this research. The goal of this study is to compare the efficacy of a wide range of canine OA interventions. This portion of the study evaluates low-dose radiation therapy in dogs with elbow osteoarthritis.

We perform local radiation to a single elbow affected with osteoarthritis, similar to dogs undergoing radiation treatment for cancer. This can be done as a three- or six-treatment session that would occur over one to two weeks. The outcome measures will include objective gait analysis (OGA; which measures your dog’s degree of lameness), physical activity monitoring (with an activity monitor attached to your dog’s collar), our veterinary exam, and questionnaires that you will have to fill out.

What is radiation therapy?

Low-dose radiation therapy (LDRT) has been used in people and dogs to treat osteoarthritis because of its anti-inflammatory nature. There are two articles that have investigated LDRT for dogs with osteoarthritis. One study reported improvement in all 23 dogs that presented for follow-up and no adverse effects were observed. However, in this study no objective outcome measures were used, and treatment efficacy was based on owner and veterinarian’s assessment. Another study reported decreased lameness (assessed objectively via objective gait analysis) in a very small group of five dogs.

What are the risks?

Radiation therapy has to be administered under general anesthesia, since the patient can not move during treatment. Besides the risk associated with anesthesia, there is very little risk associated with LDRT given the low dose administered. In the available studies in dogs, no side effects were reported. There is some concern about developing secondary cancers years down the road in both dogs and humans; however, this occurs in less than one percent of cases.

What does CSU’s protocol look like?

At CSU, we are currently recommending two protocols: three treatments of two grays over the course of approximately seven days, or six treatments of 0.5 grays over the course of two weeks. The first protocol resembles the most recent publication in veterinary medicine, the second protocol is based on the current standard of care in people. Treatments can be started on Mondays, Wednesdays, or Fridays. The anesthesia is very short; your dog will go home the same day of the treatment and should recover from the anesthesia within 24 hours. Treatments can be repeated if they wear off after a few months.

For more information about arthritis and radiation therapy, please visit these websites:

• What is radiation therapy?, CSU Flint Animal Cancer Center
• More information about canine arthritis, CSU Small Animal Orthopedic Medicine and Mobility (OMM)

Commitment

• Adhere to the study schedule
• Six visits with OMM clinical trials over 1.5 years at specific time points
• Three to six radiation treatments
• Have the ability to complete multiple required questionnaires in person at specified time points
• Have the ability to respond to email requests and phone calls within two business days