Toxicity of sequential immune therapy and radiation for cervical and thoracic spine metastases.

130Background: Palliative radiation is an effective treatment modality for spinal metastases. Expanding use of immune therapy in metastatic cancer raises concern that side effects from treatment may be exaggerated, particularly to sensitive organs such as the esophagus. This retrospective review evaluates the toxicity of combined radiation and immune therapy in patients with cervical or thoracic spine metastases. Methods: Patients receiving radiation for cervical or thoracic spine metastases from 2012-2017 were selected based on (1) concurrent use of immune therapy and radiation (within 7 days) OR radiation within 30 days following immune therapy, (2) 3D conformal or simpler treatment technique, and (3) minimum 30 days follow up from end of treatment. Patient demographics, radiation treatment parameters, immune therapy agent(s), and maximum toxicity were extracted from the medical record. Isoeffective dose was calculated using the EQD2 model, assuming α/β of 3. Statistical analyses included t tests. Resul...