Interventional oncology is an evolving branch of interventional radiology, which relies on rapidly evolving, highly sophisticated treatment tools and precise imaging guidance to target and destroy malignant tumours. The development of this field has important potential benefits for patients and the health-care system, but as a new discipline, interventional oncology has not yet fully established its place in the wider field of oncology; its application does not have a comprehensive evidence base, or a clinical or quality-assurance framework within which to operate. In this regard, radiation oncology, a cornerstone of modern cancer care, has a lot of important information to offer to interventional oncologists. A strong collaboration between radiation oncology and interventional oncology, both of which aim to cure or control tumours or to relieve symptoms with as little collateral damage to normal tissue as possible, will have substantial advantages for both disciplines. A close relationship with radiation oncology will help facilitate the development of a robust quality-assurance framework and accumulation of evidence to support the integration of interventional oncology into multidisciplinary care. Furthermore, collaboration between interventional oncology and radiation oncology fields will have great benefits to practitioners, people affected by cancer, and to the wider field of oncology.