Technical Giants But Biologic Infants: Defining a More Sophisticated Role for Local Therapy in Metastatic Disease

The role of radiation therapy in metastatic cancer is rapidly evolving with increased understanding of the oligometastatic state and improved technologies to deliver higher doses of radiation with greater precision and avoidance of normal tissues than before. Recent data have demonstrated that the use of stereotactic ablative radiotherapy (SABR) in oligometastatic disease confers a survival benefit. Yet, the current enthusiasm must be balanced with caution. Here we summarize the evidence in favor of SABR for oligometastatic patients as well as the concerns regarding rapid adoption into clinical practice and outline broad principles to guide clinical trials evaluating the role of SABR in oligometastatic disease. As oncologists, we must exercise due diligence and gather the appropriate evidence necessary to 1) understand the oligometastatic disease state and 2) optimize benefit in those patients before broadly offering SABR to all. Any alternative path forward will do our field and our patients a great injustice.