Oligometastases refer to a state of disease where cancer has spread beyond the primary site, but is not yet widely metastatic, often defined as 1–3 or 1–5 metastases in number. Stereotactic ablative radiotherapy (SABR) is an emerging radiotherapy technique to treat oligometastases that require further prospective populationbased toxicity estimates. | Population-based phase II trial of stereotactic ablative radiotherapy SABR for up to 5 oligometastases SABR-5