Imaging’s role in cancer diagnosis and treatment continues to grow in importance. At the forefront of this development is interventional oncology (IO), a rapidly expanding subspecialty of interventional radiology.
“IO’s minimally invasive nature makes it particularly advantageous, enabling a cancer to be treated with an entry point the size of a needle instead of the large cutdown or lengthy recovery of surgery,” said Nadine Abi-Jaoudeh, MD, a radiologist and director of clinical research at the University of California, Irvine.
Abi-Jaoudeh
Unlike systemic therapies, IO delivers therapies in a locoregional manner, which minimizes toxicity to other organs and even normal tissue in the affected organ. Common examples include thermal ablation, which kills a tumor by either heating or cooling it to extreme temperatures emitted from the tip of a needle introduced into the tumor, and radioembolization, which uses tiny radioactive beads deposited into the tumor to produce lethal tumoral cell damage.
Promising Results on the Use of Combination Therapies
Speaking at a Sunday educational session, Dr. Abi-Jaoudeh noted that IO is a field full of new developments and exciting discoveries. Take for example locoregional therapies’ effect on the tumor microenvironment and immune system modulation.
“Locoregional therapies produce changes in the tumor microenvironment that can induce a small immune reaction to the tumor,” she explained. “When locoregional therapies are combined with systemic immunotherapy, this immune reaction can be amplified, resulting in the immune system recognizing tumor antigens, mounting an attack and destroying the tumors.”
Dr. Abi-Jaoudeh noted the results of several pre-clinical and human trials using combination therapies to treat liver cancer and colorectal carcinoma. “Patients with widespread tumors in multiple organs who undergo combination therapy focused on one tumor in the liver may display a response in all the tumors in their body,” she said. “This is particularly exciting because immunotherapies alone have had mixed results, with great success in lung and skin cancers but very disappointing results in, for example, colorectal cancer.”
A Robust IO Pipeline
While combination strategies may have the ability to overcome the shortcomings of immunotherapy, they are just one example of the progress currently happening in interventional oncology. “There are a lot of exciting developments coming down the IO pipeline, with many new agents being explored,” said Dr. Abi-Jaoudeh.
Take for example Tirapazamine, a new type of agent that could improve the results of chemoembolization. “Unlike doxorubicin, the most common agent used with chemoembolization of primary liver cancer, Tirapazamine becomes activated in a hypoxic environment, meaning it can leverage the physiological consequences of embolization,” Dr. Abi-Jaoudeh noted.
In a phase I clinical trial, Tirapazamine embolization demonstrated very encouraging results in the treatment of primary liver cancer.
Dr. Abi-Jaoudeh also highlighted a new ablation technology called histotripsy, which is in early phase I clinical trials. “While individual ultrasound waves aren’t harmful, when they merge at the desired location their combination is lethal,” she explained. “Histotripsy focuses ultrasound waves from multiple angles onto one point, thus ensuring a very precise killing of the tumor area while sparing the adjacent tissue.”
Questions Remain Unanswered
Despite these very exciting developments, Dr. Abi-Jaoudeh notes that many questions remain unanswered. “Much of the exact pathophysiological changes in the microenvironment and immune stimulation caused by locoregional therapies remains unknown, and it appears that these changes are unique to each locoregional therapy,” she said.
However, with continued research in IO, Dr. Abi-Jaoudeh is confident that imaging guidance’s role in treating cancers will only continue to grow.
Access the presentation, “Interventional Oncology: What’s New?” (S3-CIR02) on demand at Meeting.RSNA.org.
