Retrospective Evaluation of Outcome in Dogs With Appendicular Osteosarcoma Following Hypofractionated Palliative Radiation Therapy With or Without Bisphosphonates: 165 Cases (2010–2019)

Abstract

ObjectiveTo report the survival times in dogs that received a standardized palliative-intent radiation therapy (RT) protocol for the treatment of canine appendicular osteosarcoma (OSA), alone or in combination with bisphosphonates (BPs), and to determine whether the addition of BPs affects survival. A secondary objective was to identify prognostic features that may influence outcome in dogs undergoing treatment.DesignRetrospective case series.Materials and MethodsDogs with presumed or confirmed OSA of the appendicular limb treated with daily hypofractionated RT (8 Gy x 2) at the Flint Animal Cancer Center between 2010 and 2019 were evaluated retrospectively. Clinical data were abstracted from the medical records, and adjuvant therapies were noted. Outcome was assessed using medical records and electronic follow up.ResultsOne hundred and sixty-five dogs were included. Sixty-eight dogs received BPs as a part of their palliative-intent treatment. The median survival time from first RT treatment to death was not significantly different between groups (119 vs. 109 days for BP and non-BP groups, respectively, p = 0.758). Only age (>9 years) was found to be prognostic in this population (p = 0.031). Factors that were not found to be associated with survival time included BP drug type, timing of BP administration, tumor location, weight, breed, sex, time to treatment, concurrent administration of chemotherapy, and salvage amputation.ConclusionsThis study suggests no difference in outcome for dogs treated with and without BPs in addition to hypofractionated RT. Prospective studies are needed to determine if the addition of BPs to hypofractionated RT leads to an improved quality of life in dogs undergoing palliative-intent treatment for OSA.

Nanocarriers in Veterinary Medicine: A Challenge for Improving Osteosarcoma Conventional Treatments

“…Even if the aesthetic result might be shocking at first, the functional result is good even in large breed dogs in which this neoplasia is frequently diagnosed [59,60]. Each case should be carefully and globally evaluated to understand if a dog might be a good candidate for surgery: amputations can be contra-indicated by severe obesity, concurrent orthopedic or neurological conditions, metastatic disease, and non-compliance of owners [61]. In these cases (or when owners refuse amputation), a limb sparing surgery can be performed or radiation could be applied, alone or in combination with analgesics administration, with the final aim to promote a good quality of life and reducing tumor-related clinical signs [57,61,62].…”

“…Bisphosphonates have also been tested alone or in association with palliative-intent radiotherapy: bisphosphonates are synthetic analogs of pyrophosphate with a high affinity for bone material and are able to inhibit osteoclast activity, limiting osteolysis and primary bone lesions [66]. Data reported in a retrospective study suggested that no difference could be found in dogs treated with radiotherapy, with or without the concomitant administration of bisphosphonate [61].…”