A Study of Radiation Therapy to Treat Solid Tumor Cancer That Has Spread to Soft Tissue

Inclusion Criteria: * Patients with biopsy confirmed advanced/metastatic solid tumors of the following types: invasive ductal or lobular breast carcinoma (all histological and intrinsic subtypes), non-small cell lung cancer (NSCLC, all subtypes), gastrointestinal squamous cell or adenocarcinomas (including pancreatic cancer), bladder cancer, renal cell carcinoma, melanoma, and soft tissue sarcoma (all subtypes), who require and are being planned for palliative radiation therapy to at least one site of extracranial metastatic disease measuring at least 5 cm in a single axis. If a patient, requires palliative radiotherapy to additional sites, these can be treated with standard of care SBRT per departmental guidelines. * Age ≥ 18 years * ECOG Performance Status of 0 or 1. Exclusion Criteria: * Patients who are pregnant or breastfeeding * Prior radiation therapy to the candidate metastatic sites under consideration for treatment ("re-irradiation" is disallowed). * Medical condition such as uncontrolled infection (including HIV), uncontrolled diabetes mellitus, or connective tissue diseases (lupus, systemic sclerosis, or other collagen vascular diseases) that, in the opinion of the treating physician, would make this protocol unreasonably hazardous for the patient. * Patients with a "currently active" metastatic second malignancy. * Patients on oral or parental corticosteroids. Physiological doses of steroids are permitted (eg for patients with adrenal insufficiency). If patients are on supraphysiological doses of steroids, these must be discontinued and held during the period of the study. * Concomitant anti-neoplastic treatment is not allowed during the days of radiation treatment delivery and should be completed or held for 3 days prior to commencement of protocol treatment and for 3 days following completion of radiotherapy, or with resolution of associated acute toxicities. * Unwilling or unable to participate in all required study evaluations and procedures. * Unable to understand the purpose and risks of the study and to provide a signed and dated informed consent form (ICF) and authorization to use protected health information (in accordance with national and local patient privacy regulations).