Finding minimally invasive ways to treat liver cancer and being able to customize that treatment individually to patients is a hallmark of interventional radiologists. New research is focused on the recent advances in yttrium-90 (Y-90) radioembolization for liver cancer, a leading cause of cancer death worldwide.

The new studies were reported in the October 2011 issue of the Journal of Vascular and Interventional Radiology (JVIR). “Results of these two new studies may be beneficial to patients with liver tumors that cannot be surgically removed,” said Daniel Sze, MD, PhD, FSIR, professor of interventional radiology at Stanford University Medical Center (Stanford, CA, USA). “These studies address methods to modify the blood vessels of the liver in order to maximize delivery of tumor-killing material to the targets and to make treatment simpler and safer.”

“Blood supply to tumors can be complex and can present challenges for interventional radiologists,” said Riad Salem, MD, MBA, FSIR, who wrote an accompanying commentary in JVIR. “This research advances the field and provides information that is immediately applicable to all interventional radiologists when treating their cancer patients,” said Dr. Salem, professor of radiology, medicine, and surgery and director of interventional oncology, division of interventional radiology, in the department of radiology at Northwestern University (Chicago, IL, USA). “Such research allows interventional radiologists to tailor treatments to help even the sickest patients achieve a better quality of life,” he explained.

Worldwide, primary liver cancer accounts for an estimated 600,000 deaths annually. Moreover, about 10 times as many patients succumb to liver cancers that metastasize from other areas. Many of these patients may be treated with Y-90 radioembolization. With Y-90 radioembolization treatment, radioactive microspheres are injected through a catheter from the groin into the liver artery supplying the tumor. The beads become lodged within the tumor vessels, where they emit radiation locally that causes tumor cells to die. This technique allows for a very high local dose of radiation to be delivered, with little hazard from radiation to the healthy tissues in the body, according to Dr. Salem.

Whereas radioembolization is palliative, the treatment benefits patients by extending lives and by improving symptoms and is tied to fewer side effects than conventional treatments for cancer. Interventional radiologists have long examined the use of intra-arterial therapies for cancer and developed yttrium-90 radioembolization since its introduction in 2000 to treat liver cancer.

One study showed promising results in a group of 35 patients in whom the “thirsty tumors” had recruited blood vessels from outside the liver, a situation that interferes with complete delivery of Y-90 microspheres to the tumors, explained Dr. Sze. “These ‘parasitized’ blood vessels were successfully embolized, before administration of Y-90 microspheres, reestablishing the blood supply from within the liver to enable the successful delivery of the microspheres to the targeted tumors,” said Dr. Sze, senior author of the study.

“While large, multicenter studies will be necessary to further confirm the proof of the concept, it is notable because the Stanford University researchers investigated the idea of simplifying blood supply in order to permit a direct injection of microspheres into the tumor,” said Dr. Salem.

In a related report, the same team was able to make treatment simpler and safer by blocking extra (variant) arteries that almost half of normal people have and utilizing collateral (detour) vessels inside the liver to assist in microsphere delivery. “After blocking these variant arteries, we were able to treat nearly 100% of tumors through the main hepatic artery--taking advantage of the networks of blood vessels within the liver,” reported Dr. Sze.

“By embolizing small, less important vessels to the tumors, one main arterial channel was created that could treat the entire area in a technically simple and practical way,” Dr. Salem explained. He also noted that these principles might be applicable to other embolization procedures, such as drug-eluting bead chemoembolization using microspheres that have been impregnated with a chemotherapy agent instead of radioactivity. “Based on this research, more people who are not good candidates for surgery will benefit in several ways,” he explained. “Whenever we can administer chemotherapy directly to a tumor, we limit the drug’s entrance into the patient’s bloodstream and thus lessen the spread throughout the body and the associated consequences and side effects. This method of delivering chemotherapy provides an additional advantage by releasing the drug slowly, destroying the tumor over a greater period of time. The new techniques applied to radioembolization may also be applied to chemoembolization,” noted Dr. Dr. Salem.

In another study, Thomas Jefferson University (Philadelphia, PA, USA) researchers examined the results of liver function tests from 29-571 days following treatment in 81 patients who received 122 Y-90 infusions to treat primary or metastatic liver tumors. “Radioembolization with resin microspheres is a safe treatment for patients with unresectable, or inoperable, hepatic malignancies,” concluded Daniel B. Brown, MD, FSIR, an interventional radiologist and chief of interventional radiology and interventional oncology at Jefferson. “More than 90% of the individuals in our study who received infusions showed no, or few, changes in liver function. And, generally speaking, almost all patients receiving Y-90 infusions to treat primary or metastatic liver tumors were asymptomatic after treatment,” he added.

“JVIR is committed to publishing important research that could be practice-changing,” noted JVIR editor-in-chief Ziv J Haskal, MD, FSIR. “Studies such as these allow interventional radiologists, whose hallmark is minimally invasive, targeted treatment of disease, to tailor treatments to help even those who are not candidates for surgery live longer and achieve a better quality of life,” added Dr. Haskal, who is also professor of radiology and surgery at the University of Maryland School of Medicine and vice chair of strategic development and chief of vascular and interventional radiology, image-guided therapy and interventional oncology at the University of Maryland Medical Center, both in Baltimore (MD, USA).
 

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