Cancer is the leading cause of death in Canada, comprising 30% of all death events. In 2017, an estimated 206,200 new cancer cases and 80,800 deaths occurred. The development of metastases is a potential, and sometimes frequent, complication among patients with localized cancer. Metastases occurs when cancer cells originating from one part of the body moves from the place of origin (primary tumor) and spreads to another location to form one or more tumors. The extent of systemic disease and the number, size, and location(s) of lesions can affect the overall prognosis of a patient. In 1995, Hellman and Weichselbaum first introduced the term oligometastatic state, which acknowledges that the process of cancer metastasis occurs along a continuum – from locally confined cancers to widespread metastatic disease. Oligometastatic state is believed to be curative in select patients. Since the publication of this seminal paper, the concept of oligometastasis has been well accepted but the specific criteria of what defines oligometastatic state, such as what is considered ‘metastases limited number’, is still an ongoing process. Currently, the National Cancer Institute, part of the National Institutes of Health, defines oligometastasis as “a type of metastasis in which cancer cells from the original (primary) tumor travel through the body and form a small number of new tumors (metastatic tumors) in one or two other parts of the body.” However, other factors may also play an important role in establishing criteria for oligometastatic state such as volume, histology, genetics and location of tumor(s). Nevertheless, treatment options for patients presenting with oligometastatic cancer may include, but are not limited to, surgery or stereotactic body radiotherapy. Though surgery (i.e., surgical resection) is considered the gold standard for the treatment of certain oligometastases (e.g., hepatic, colorectal), stereotactic body radiotherapy may be a non-invasive alternative to achieve local control. Stereotactic body radiotherapy, also known as stereotactic ablative radiotherapy, is a type of external radiation therapy that helps spare normal tissue by precisely delivering radiation to tumors in the body (except the brain); the total dose of radiation is divided into smaller doses given over several days. Ultimately, the feasibility of stereotactic body radiotherapy as a standard of care will depend on its clinical and cost-effectiveness compared to other cancer treatments. Thus, this report aims to summarize the evidence regarding the clinical effectiveness and cost-effectiveness of stereotactic body (ablative) radiotherapy for patients with oligometastatic cancer.