Which radiotherapy plan best eases bone metastasis symptoms?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age 18 or older * Able to provide informed consent * Clinical diagnosis of cancer with bone metastases (biopsy not required) * Currently being managed with palliative intent RT to 1-3 RT fields for bone metastases, at least one RT field (PTV) must (at least) partly lie within T11-L5 or pelvis. * ECOG Performance Status 0-3 * Patient has been determined to potentially benefit from 8 Gy or 20 Gy * Radiation Oncologist is comfortable prescribing 8 Gy in 1 fraction or 20 Gy in 5 fractions RT for bone metastases * Negative pregnancy test result for women of child-bearing potential * The baseline assessment must be completed within required timelines, prior to randomization. * Patients must be accessible for treatment and follow-up. Investigators must assure themselves the patients randomized on this trial will be available for complete documentation of the treatment, adverse events, and follow-up. * For simplicity of planning, expected GTV should be less than 20 cm based on radiological or clinical evidence * Patient must be prescribed a 5-HT3 receptor antagonist (e.g. Ondansetron) as antiemetic prophylaxis prior to RT start. * Patient is able and willing to complete the quality of life questionnaires, and other assessments that are a part of this study, via paper or using PatientPortals.ca or REDCap if they provide their email address on the informed consent Exclusion Criteria: * Serious medical co-morbidities precluding radiotherapy * Clinical evidence of spinal cord compression * Spinal cord in treatment field has already received at least \>30 Gy EQD2 * Whole brain radiotherapy (WBRT) within 4 weeks of RT start or planned WBRT in the first 4 weeks after last RT * Solitary plasmacytoma * Pregnant or lactating women * Target volume cannot be encompassed by a single VMAT isocentre * Custom mould room requirements (shells and other immobilization that is standard-of-care is acceptable) * Greater than two organs-at-risk requiring optimization. * Patients requiring treatments outside standard clinical hours * Implanted electronic device within 10 cm of the RT fields * Prostheses in the axial plane of the target, or within 1 cm of the PTV out-of-plane * Previous RT that requires an analysis of cumulative dose (i.e. sum plans or EQD2 calculations) * Oral or IV contrast if the local standard-of-care requires compensation for this in planning.