Y-90 Radioembolization: TheraSpheres & SIR-Spheres

SIR-Spheres microspheres are an innovative means of treating liver cancer. In cases where it is not possible to surgically remove the liver tumors, SIR-Spheres microspheres can be used to deliver targeted, internal radiation therapy directly to the tumor.

This technique uses millions of tiny polymer beads or microspheres which contain a radioactive element called yttrium-90. SIR-Spheres microspheres are very small, approximately 32 microns in size, and are about one-third the diameter of a strand of hair. SIRT is usually administered as an outpatient procedure by a specially trained physician known as an interventional radiologist. A small catheter is guided into the liver and the SIR-Spheres microspheres are infused through the catheter.

The microspheres with the radioactive yttrium-90 are carried by the bloodstream directly to the tumors in the liver where they preferentially lodge in the small vessels feeding the tumor and deliver their dose of radiation. Unlike conventional external beam radiation, which can only be applied to limited areas of the body, SIR-Spheres microspheres selectively irradiate the tumors and therefore have the ability to deliver more potent doses of radiation directly to the cancer cells over a longer period of time.

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How Do I Qualify?

Patients suitable for treatment with SIR-Spheres microspheres need to establish that they:

• Have inoperable metastatic colorectal cancer, that is, cancer that originated in the bowel and has spread to the liver.
  
• Have the liver as the major site of disease
  
• Have sufficient remaining healthy liver still functioning satisfactorily (this can be determined by a simple blood test)
  
• Meet the pre-selection criteria established by the doctor's pre-treatment testing

An angiogram will be needed to determine that the liver's vasculature is acceptable to receive SIR-Spheres microspheres.

Basic testing generally includes standard blood tests and a chest X-ray or CT scan of the chest to rule out cancer in the lungs.

What Are The Side Effects?

Patients should not have any serious side effects when SIR-Spheres microspheres are correctly administered and do not lodge outside the liver. However, during the infusion of the SIR-Spheres microspheres you may experience some pain. If you do, your doctor will provide medication to help alleviate any discomfort during the infusion. Sometimes patients develop pain in the abdomen that may last for a few hours after the administration of SIR-Spheres microspheres, but this can also be treated with medication. Some patients develop a fever that may last for up to a week. Some patients may develop nausea, but this subsides with time and medication. Most frequently, many patients feel lethargic with a poor appetite for several days after the treatment, but this also subsides with time. Patients are often placed on medication for the first month after treatment with SIR-Spheres microspheres to prevent gastritis and peptic ulceration.

There is always the potential of serious side effects if the SIR-Spheres microspheres are incorrectly delivered into the artery supplying blood to the liver. In this case, the SIR-Spheres microspheres could be inadvertently supplied to the stomach, duodenum, pancreas or other organs, resulting in very severe and even fatal side effects. Radiologists delivering SIR-Spheres microspheres are given special training to inform them of this risk and to prevent this from happening. The dose of radiation is individually prescribed for each patient. If the dose is too high, some patients could develop long-term damage to the normal liver.

How soon after the procedure can I go home?

Usually, patients treated with SIR-Spheres microspheres can go home the same day of treatment and resume normal activity. However, your doctor might keep you in hospital for observations to ensure that you do not develop any complications resulting from the treatment with SIR-Spheres microspheres. Your doctor will decide what is best for you.

Will my insurance cover this procedure?

Most insurance companies generally cover the cost of SIR-Spheres microspheres. Under the terms of the 2003 Medicare Prescription Drug Improvement and Modernization Act, Medicare reimburses hospitals for the full cost of outpatient treatment with SIR-Spheres microspheres.

Download SIR-Spheres microspheres Procedure Consent Form

Y-90 TheraSphere®

The need for a new treatment

All currently used treatments for unresectable (inoperable) liver cancer that reduce the symptoms of this disease require hospitalization, and usually cause side effects that reduce the quality of life for patients. For example, chemotherapy and chemoembolization often produce nausea, vomiting and hair loss.

As a result, there is a need for new treatments that offer the convenience of outpatient therapy and fewer and milder side effects.

Localized internal radiation - Taking advantage of tumor vascularity

TheraSphere® builds upon growing medical knowledge of liver structure and function and previous experience with other types of therapy to offer a new, more convenient treatment option. TheraSphere® also builds on knowledge physicians have gained in recent years with brachytherapy, radioactive implants that are now increasingly used to treat prostate cancer.

Previous attempts to treat liver cancer with radiation from external sources (radiation beam therapy) showed some easing of symptoms, suggesting that liver cancer is sensitive to radiation. But there is a major drawback to external radiation: it cannot be tightly focused on the tumor, but instead, affects a larger area of the body that includes the tumor.

This lack of precise focus exposes healthy areas of the body to radiation and produces unpleasant side effects, including changes to healthy tissue, nausea and vomiting. Therefore, researchers began to develop ways to place radiation directly into the liver, targeted as precisely at the tumors as possible, with the least effect on healthy liver tissue or surrounding organs.

To direct TheraSphere® treatment at tumors in the liver, a physician first makes a small incision in the patient's leg and places a long, flexible plastic tube called a catheter, into the femoral artery, which is the major blood vessel in the leg. Guided by fluoroscopy (an X-ray imaging technique that projects views of the inside of the body onto a screen) the physician then moves the catheter up through the blood vessels to the hepatic artery, which is one of two blood vessels that feeds the liver. The physician guides the catheter into the branch of the hepatic artery that feeds the cancerous tumor in the liver and infuses the TheraSphere® beads through the catheter into the blood that supplies the tumor. This is usually performed in a hospital's radiology suite and patients remain conscious throughout the procedure.