Osteosarcoma is the most common primary bone tumor in dogs and while amputation followed by systemic chemotherapy is the standard of care, it may not be the most appropriate treatment option for all dogs or it may not meet the goals of individual owners. Palliative radiation therapy can provide significant pain relief for dogs who present with lameness and pain caused by osteosarcoma; however, the addition of bisphosphonates to radiation therapy is frequently recommended but without concrete evidence that it provides additional benefit. Anecdotally, improvement in pain response has been reported in children and young adults that receive chemotherapy for osteosarcoma. Similar effects have also been reported in dogs. In the veterinary literature, there are limited studies that support an improvement in onset to response of pain relief, improvement in duration of pain relief, and improvement in survival time when chemotherapy is combined with palliative radiation therapy. With this trial we aim to answer the questions of whether the addition of bisphosphonates or carboplatin chemotherapy provides improved pain relief from bone tumors compared to palliative radiation alone.

When patients undergo fractionated radiation therapy, maintaining appetite, consistent stools, and body weight are incredibly important for patient well-being and quality of life. The most common non-radiation complications in dogs undergoing these longer radiation protocols include diarrhea, vomiting or regurgitation, and decreased appetite. When these complications happen in patients, both owners and clinicians attempt to offer a multitude of foods, home cooked diets, probiotics, appetite stimulants, anti-nausea medications, or antibiotics. Recently nutritionists and veterinarians at a well-known pet food manufacturer developed a prescription diet designed to specifically help nourish and support dogs that are fighting cancer. This diet is highly digestible and contains a proprietary blend of prebiotic fibers to help support a healthy gastrointestinal microbiome to provide consistent stool quality. The goal of this study is to evaluate the acceptance of the novel diet through food intake and eating enthusiasm data by dogs undergoing daily, definitive intent radiation therapy, and to examine the differences in body weight changes, muscle condition scoring, body condition scoring, body fat index, quality of life, and stool consistency over time in dogs receiving the novel vs control diet.If your dog participates in this study, he/she will have blood work, urine panel, fecal analysis, and will be randomized to receive one of the two study foods during radiation therapy. Blood work and fecal analysis will be performed prior to starting radiation therapy, half way through radiation, at the end of the radiation protocol and two weeks after completing radiation. Urine panel will be performed prior to starting radiation, at the final radiation dose, and at the two week recheck. We will assess intake of the diet and enthusiasm of the diet twice weekly. We ask that you also record food intake and eating enthusiasm twice a week, fecal scores at each defecation, and quality of life weekly with provided guides and questionnaires. You and your clinical team will be blinded to which diet your dog is receiving, but this will be revealed at the conclusion of the study period.

Osteosarcoma is the most common primary bone tumor in dogs and, while amputation followed by systemic chemotherapy is the standard of care, it may not be the most appropriate treatment option for all dogs or it may not meet the goals of individual owners. Stereotactic body radiation therapy (SBRT) has been utilized to kill tumor cells while leaving the affected limb intact showing good primary tumor control rates. The biggest risk with using SBRT in this setting is the potential for pathologic fracture of the affected limb. Here we plan to use a dual energy CT for radiation planning and to quantify bone mineral density (BMD) both before and after SBRT to assess changes that happen with SBRT treatment. BMD measures calcium and other minerals. In theory, the more mineral, the denser and stronger the bone is and less likely it is to break. In addition, we will measure bone breakdown markers before and after treatment to determine how these are correlated with the BMD and response to treatment.Once enrolled, dogs will have blood and urine collected for bone breakdown markers followed by 3 doses (or fractions) of SBRT. On the third and final fraction, dogs will receive the first dose of standard of care chemotherapy (carboplatin). Two weeks after chemotherapy, your dog will need to have a complete blood count performed to assess response to chemotherapy as well as blood and urine collected for the bone breakdown markers. At each dose of chemotherapy, a total of 6, blood and urine will be collected to assess trends in these markers. At the time of the final chemotherapy treatment, an additional dual energy CT will be performed to assess the changes that happen to the bone after treatment. Once chemotherapy is complete, it is recommended that your dog return every 8 weeks for chest x-rays; blood and urine will be collected for the study at the 1st 3 visits post-chemotherapy. At any change in lameness or concern for progression of disease, it is expected that your dog will return to CSU for assessment and evaluation of the bone markers.