Clinical trials of interventional oncology

Interventional oncology has great potential to be a good treatment modality in the field of oncology, because its procedures are minimally invasive and fairly quick. However, except for a few procedures such as percutaneous radiofrequency ablation and trans-catheter arterial chemo-embolization that have been recognized as standard treatments for hepatocellular carcinoma, most procedures have not been established as the standard treatment modality due to the limited number of clinical trials with compelling evidence. There are several common problems when performing clinical trials of interventional oncology. The first is that the outcomes of clinical trials are greatly influenced by the level of technical skill of the physicians. The second is that equipment and devices vary widely in countries and regions, and they also influence the outcomes. The third is that the methodology of clinical trials for techniques such as interventional oncology has not yet been established. The fourth is the difficulty of setting appropriate endpoints; quality of life is suitable for evaluating interventional oncology in palliative care, but it is not easy to set as the endpoint. The fifth is the difficulty of employing a blinded design, because the procedure cannot be performed without the physician's awareness. Despite such difficult situations, many multi-institutional clinical trials of interventional oncology have been carried out in Japan, with some challenging results. Establishing evidence is critical to making interventional oncology the standard treatment. Interventional radiologists should know the importance of clinical trials, and should move ahead in this direction in a step-by-step manner.