Interventional oncology (IO) is a rapidly growing subspecialty of interventional radiology that focuses on using minimally invasive image-guided procedures to diagnose and treat cancer. It has become an established and important part of modern cancer care, alongside surgery, radiation therapy, and medical oncology, and is often referred to as the “fourth pillar” of cancer treatment. IO procedures are performed using thin catheters inserted through the skin or blood vessels. This means they cause less pain, scarring, and bleeding than traditional open surgery.