Active_comparator: Arm 1 - Standard of Care

Participants on Arm 1 - SOC will be treated as per standard of care by their treating Oncologist. In most instances, it is anticipated participants will undergo a change in Systemic Therapy (ST) (including best supportive care). The ST will be at the discretion of the Oncologist and patient, according to best practices for the patient's diagnosis and clinical scenario. Patients can receive palliative radiotherapy for standard indications at any time.

Experimental: Arm 2 - Experimental

Participants on Arm 2 - Experimental will receive standard of care SBRT to oligoprogressive sites according to institutional standards while remaining on the systemic treatment prescribed by the treating oncologist.