A Comparative Study on Radiosensitivity of Canine Osteosarcoma Cell Lines Subjected to Spatially Fractionated Radiotherapy.

Canine appendicular osteosarcoma (OSCA) is a highly aggressive cancer, constituting 85% of all bone tumors in dogs, predominantly affecting larger breeds and exhibiting a high metastatic rate. This disease also shares many genomic similarities with human osteosarcomas, making it an ideal comparative model for treatment discovery. In this study, we characterized the radiobiological properties of several OSCA cell lines when subjected to spatially fractionated radiation therapy (SFRT) and chemotherapy. Specifically, we focused on lower (peak) doses from SFRT ranging from 1 to 10 Gy. These canine OSCA cell lines serve as useful models for osteosarcoma research that can be utilized to find translational treatments for both canine and human patients. This study reaffirms established clinical wisdom regarding the notoriously radioresistant profile of osteosarcomas but additionally offers compelling evidence supporting SFRT as a promising treatment option that could be used in conjunction with other cytotoxic agents.