Trial to Test Radiation-Emitting Microspheres Against Inoperable Liver Cancer

The therapy entails injecting tiny beads that emit small amounts of radiation into the liver's main artery while also blocking the blood supply feeding the tumor's growth.

The technique, called radioembolization, has been approved by the U.S. Food and Drug Administration (FDA) for use in advanced liver cancer. This is the first time that the particular technology, called SIR- (selective internal radiation)-Spheres microspheres, which is FDA-approved for treating colon cancer that has metastasized to the liver, is being evaluated in patients with hepatocellular carcinoma, or primary liver cancer (one that originates in the liver). The trial led by Brian Carr, M.D., FRCP, Ph.D., professor of medical oncology at Jefferson Medical College of Thomas Jefferson University (Philadelphia, PA, USA) includes patients from the University of Texas' M.D. Anderson Cancer Center (Houston, TX, USA) and the University of Pittsburgh (PA, USA).

According to Dr. Carr, who is chief of the liver tumor program at the Kimmel Cancer Center and Thomas Jefferson University Hospital, the technique uses approximately 30-times more beads than other types or radioembolization. The teams plan to enroll 10 patients initially, and possibly as many as 40. "No one knows if radioembolization will be better than just radiation, even though there are theoretical grounds for it,” he noted.

In the form of radioembolization being assessed, millions of tiny beads or "microspheres” containing the radioactive isotope yttrium-90 are injected through a catheter directly into the liver's hepatic artery, which also supplies blood to tumors. The microspheres, in addition to blocking blood flow to the tumor, emit targeted radiation directly to the cancer, sparing healthy tissue.

Dr. Carr and his colleagues are encouraged by results from a recent clinical trial demonstrating the effectiveness of a similar technique against advanced liver cancer. Dr. Carr and physicians at Northwestern University (Chicago, IL, USA) recently discovered that injecting another type of yttrium-90-containing beads (TheraSphere) was effective in treating inoperable liver cancer even in patients whose portal vein was blocked by tumor. The treatment, according to Dr. Carr, was as good as or better than using the current standard called chemoembolization, which involves directly injecting chemotherapy drugs into the liver through the hepatic artery. Because it involves harmful, cell-killing drugs, he noted, doctors have looked for liver cancer treatments that have fewer toxic effects.

The treatment does not cure the cancer, but it has been shown to frequently shrink tumors and help patients live longer. The treatment can also be used for patients who have previously failed chemotherapy. "This extends the numbers of patients who can be treated with this, much safer treatment,” Dr. Car stated. "Using TheraSphere is just as safe with or without portal vein thrombosis, so it looks like it's a wonderful new treatment. It's much safer because these patients don't get chemotherapy side effects, such as nausea, hair loss, and they generally don't need to be in the hospital except for the day of treatment, which is usually every three months. The immediate objective is to get patients to live longer and ultimately, a cure. Right now, the choices are surgery and or transplant. Ideally, if the radioembolization trial were successful, many of these patients would have their liver tumors shrunken to the point where surgery is possible. Some may be able to have a transplant. It would be a significant contribution to the field if we could downstage the tumors so we could do more transplants, which is the only cure.”

TheraSphere was developed by MDS Nordion (Ottawa, Canada).


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Thomas Jefferson University
MDS Nordion