Cancer: Radioembolization (Yttrium 90)


If you or a loved one has been diagnosed with primary liver cancer or cancer that has spread (metastasized) to the liver, it is important to learn the facts and evaluate your treatment options.

Yttrium-90® microspheres and Theraspheres®, offered at VISOC, are a targeted radiation therapy that delivers a dose of internal radiation up to 40 times higher than conventional external beam therapy while sparing healthy tissue. This maximizes the treatment’s effectiveness and reduces the risk of injury to the liver. The treatment is typically administered as an outpatient procedure. Yttrium-90 SIR-Spheres® microspheres are the only fully FDA-approved microspheres for patients with inoperable metastatic colorectal cancer to the liver. Theraspheres® is approved by the U.S. Food and Drug Administration (FDA) under a Humanitarian Device Exemption (HDE).

Directly treating a liver tumor with yttrium-90 kills tumor cells while preserving healthy liver tissue Yttrium-90 microspheres are designed to treat liver tumors with beta radiation.

How is Yttrium-90 administered?

Yttrium-90 microspheres are administered through a process called Selective Internal Radiation Therapy (SIRT). During the procedure, an interventional radiologist makes a small puncture, usually into the femoral artery near the groin. A small flexible tube, known as a catheter is then guided through the artery into the liver and millions of microscopic spheres (about a third of the width of a human hair), are delivered directly into the tumor. The entire procedure takes about 90 minutes. Patients will be sleepy during the procedure but able to communicate with the doctor and the team. Most patients return home four to six hours following treatment.

The interventional radiologist makes a small puncture, usually into the femoral artery near the groin. A small flexible tube, known as a catheter is then guided through the artery into the liver.

  1. Liver anatomy, with presence of inoperable tumors
  2. Normal liver tissue is highlighted – this tissue receives its blood supply from the portal vein
  3. Tumors receive their blood supply from the hepatic arteries
  1. Tumors can be selectively irradiated leaving normal tissue unaffected
  2. A micro-catheter is advanced into the hepatic artery
  3. SIR-Spheres microspheres are released into the arterial blood supply

How do Yttrium-90 microspheres work?

The SIRT procedure delivers radiation, which is often used to treat cancer, directly into the liver tumors by using the tumor’s own blood supply. Normal liver tissue takes about 90 percent of its blood supply from the veins, while liver tumors receive about 90 percent of their blood supply from arteries. This allows Yttrium-90 microspheres to target the liver tumors with a tumor-killing dose of radiation via the hepatic artery, while sparing surrounding healthy liver tissue. This typically isn’t possible with conventional external beam radiation.

How are Yttrium-90 microspheres different from other radiation treatments for cancers of the liver?

Yttrium-90 microspheres usually either reduce or eliminate liver tumors after just one treatment. The targeted nature of Yttrium-90 microspheres therapy enables doctors to deliver more radiation to the liver tumors than would be possible using conventional radiotherapy. Also, because traditional radiation is delivered to a general area of the body where cancer exists, it is less exact than Yttrium-90 microspheres. Another limitation of conventional radiotherapy is that it can only be applied to certain areas of the body, often not including the liver. Yttrium-90 microspheres, however, are designed specifically for delivery directly to the liver.

What are the goals of treatment using Yttrium-90 microspheres?

Clinical trials have shown SIRT increases the time-to-disease progression and overall survival without adversely affecting the patient’s quality of life. In clinical studies, Yttrium-90 microspheres have been combined with modern chemotherapy or administered as a monotherapy during a chemotherapy holiday and have been proven to:

  • Decrease the tumor burden in the liver
  • Increase time-to-disease progression
  • Increase survival time
  • Potentially downsize tumors to liver resection or ablation
  • Provide palliation of symptoms

What side effects and complications can I expect?

When properly administered, most side effects are typically mild and subside within several days. Post treatment side effects can include abdominal pain and/or nausea which normally subside after a short time and/or with routine medication. Patients may also develop a mild fever that may last up to a week and fatigue which may last for several weeks. As a precaution, we may recommend additional medications with the aim of preventing or minimizing these side effects.

In rare instances there is a possibility that a small number of microspheres may inadvertently reach other organs in the body, such as the gall bladder, stomach, intestine or pancreas. If Yttrium-90 microspheres reach these organs, they may cause inflammation of the gall bladder (cholecystitis), stomach (gastritis) or intestine (duodenitis). These complications are rare, but if one of these occurs, they will require additional treatment. Your treatment team will have received special training to minimize these risks and to prevent them from happening.

Patient Information Video