About IO

Interventional oncology (IO) therapies use image-guided, minimally invasive procedures to target cancer and cancer-related diseases deep inside the body. Therapies are delivered through incisions in the skin as small as pinholes, reducing time, pain, and risk to cancer patients. As the fastest growing pillar of modern oncology care, IO is driven by technological innovation and focused on three main areas of cancer intervention: diagnosis, therapy and symptom management.

Cancer Diagnosis: IO practitioners use image guidance to obtain tissue for cancer diagnosis and individualized care.

Cancer Treatment: IO precisely delivers therapeutic agents into tumors through the use of intravascular catheters and direct intratumoral injection. It targets tumors using image guided delivery of devices and agents to eradicate tumor cells or for combination therapy. For certain early stage cancers, the use of minimally-invasive ablative techniques using specialized probes can completely eradicate the tumor.

Cancer Symptom and Pain Management: IO symptom relief techniques includes techniques that reduce pain in patients suffering from cancer, improving their quality of life and ability to manage additional cancer treatments.

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An interesting problem in the medical field is, ‘How do we get rid of bad cells without getting rid of good cells?’ IO allows us to use tools to precisely target locations where cancer is present and deliver solutions that can make this distinction, between healthy and non-healthy, cancer and not cancer.
– Isabel G. Newton, MD, PhD, 2024 Annual Scientific Meeting Workshops Chair

IO Research

Research in interventional oncology is essential to bolstering the level of evidence demonstrating favorable patient outcomes from IO procedures. Hundreds of clinical studies have been completed in the field or are underway. SIO’s physician community is leading the way for this important research to continue.

We’ve seen tremendous progress in interventional oncology. Now we have IO procedures and techniques incorporated in the NCCN guidelines for multiple cancer types. We must continue to expand the concept of imaging guidance to provide precision in cancer therapy for multiple organ systems and allow more patients to benefit from these techniques. High quality data and the importance of clinical trials must become fundamental in what we do, and this is part of the overall educational efforts SIO is providing, to include the importance of research in clinical trials in the overall education for IO practitioners.
– William Rilling, MD, FSIR, Industry Advisor, SIO Board of Directors

How is research in IO impacting cancer care?

IO and Immunotherapy

Interventional oncology is a subspecialty field of interventional radiology that addresses the diagnosis and treatment of cancer and cancer-related problems by using targeted minimally invasive procedures performed with image guidance. Immuno-oncology is an innovative area of cancer research and practice that seeks to help the patient’s own immune system fight cancer. Both interventional oncology and immuno-oncology can potentially play a pivotal role in cancer management plans when used alongside medical, surgical, and radiation oncology in the care of cancer patients. (1)

To learn more about the future of immunotherapy in IO, read Immunotherapy and the Interventional Oncologist: Challenges and Opportunities—A Society of Interventional Oncology White Paper.

IO Therapies


This is a minimally invasive treatment that delivers radiation directly to the liver to treat liver tumors. These procedures target cancer tumors in the liver while limiting side effects to the healthy parts of the organ. 


This treatment directly delivers chemotherapy into the blood vessels that feed cancerous tumors without exposing the rest of the body to the chemotherapy drug. These procedures use image guidance to direct catheters and intratumoral injections. 

Ablation procedures (Cryoablation, Microwave, Radiofrequency)

These treatments use the direct application of heat (microwave and radiofrequency) or cold (cryoablation) to eradicate tumor cells while preserving the healthy portions of the affected organ. These procedures have been shown to be just as effective as surgery in some tumor types. 

History of IO

While interventional oncology (IO) is a relatively young field, its history spans many decades. Born out of the specialty of interventional radiology, interventional oncology (IO) encompasses the rapid growth in the use of minimally invasive techniques to treat cancer and manage its symptoms. Early IO studies were published in the 1950’s and 1960’s, assessing blood supply to tumors (1) and preliminary data on the value of angiographic techniques to deliver these precise treatments to cancer cells (2).

In the 1970’s, catheter embolization, an interventional technique used to stop blood flow to tumors, demonstrated the ability of these procedures to treat solid tumors in the liver, kidney, skeleton, and other organs (3,4) in patients who may not have been optimal candidates for surgical procedures. In the 1980’s, chemoembolization and other therapeutic agents were adopted for treatment for hepatocellular carcinoma (HCC).

Over the last four decades, the combination of research and increasingly sophisticated technology have made it possible for multiple IO therapies to emerge and demonstrate effectiveness in treating many cancer types. Together with its sister pillars in cancer treatment – medical, surgical, and radiation – interventional oncologists play a critical role on the cancer care team, treating patients in clinics, hospitals, and serving on tumor boards and multi-disciplinary treatment teams (5).  In 2017, the Board of Directors established the Society of Interventional Oncology as the only membership-based organization wholly dedicated to the emerging field of IO. Today, the society continues to provide research and education opportunities to practitioners in IO worldwide.


  1. Bierman HR, et al. (1951) Apr;11(5):891-905.  Studies on the blood supply of tumors in man. II. Intra-arterial nitrogen mustard therapy of cutaneous lesions. J Natl Cancer Inst.
    Deitrich RS, Cope C, et al. (1962) Oct;23:31-8. Clinical trial with alanine mustard. Cancer Chemother Rep. 

  2. Baum S, Kuroda K, Roy (1965) Dec;3(3):583-99. The value of special angiographic techniques in the management of patients with abdominal neoplasms.

  3. Am J Roentgenol (1975) 123: 57-562. Transcatheter embolization of renal cell carcinoma.  

  4. Doyon D, Mouzon A, Jourde AM, Regensberg C, Frileux C. (1974) 17(6):593-603. Hepatic, arterial embolization in patients with malignant liver tumours (author’s transl). Ann Radiol (Paris).

  5. Erinjeri J. et al. (2019) Vol. 292, No. 1. Immunotherapy and the Interventional Oncologist: Challenges and Opportunities - A Society of Interventional Oncology White Paper. Radiology.