Selective Internal Radiation Therapy
Selective Internal Radiation Therapy (SIRT) is a revolutionary treatment for advanced liver cancer that utilizes new technologies to deliver radiation directly to the site of tumors.
Conventional radiotherapy can only be applied to limited areas of the body, and it adversely affects nearby tissues. The liver can only tolerate small doses of external radiotherapy. SIRT, on the other hand, involves the delivery of millions of microscopic radioactive spheres, called SIR-Spheres®, directly to the site of the liver tumors, where they selectively irradiate the tumors. The targeted nature of SIRT enables doctors to deliver up to 40 times more radiation to the liver tumors than would be possible using conventional radiotherapy. Although normal liver tissue will be radiated to some extent, the radiation dose is well below the limit the tissue can tolerate without serious damage.
The anti-cancer effect is concentrated in the liver and there is little effect on cancer at other sites such as the lungs or bones.
Frequently Asked Questions
What are Sir-Spheres microspheres?
SIR-Spheres microspheres are microscopic resin beads that contain the radioactive isotope Yttrium-90 (Y-90) and emit radiation to kill cancer cells. Due to their small size (1/3 the width of a human hair) and similar density to blood cells, the microspheres travel easily with the bloodstream directly to the liver tumors. The microspheres become lodged inside the tumor and kill the cancer cells through radiation. Selective Internal Radiation Therapy (SIRT) with SIR-Spheres microspheres is considered a well-tolerated and effective method of using radiation to treat colorectal cancer that has spread to the liver and is often used in conjunction with chemotherapy
Who Is eligible to receive treatment?
SIR-Spheres microspheres are the only fully FDA PMA-approved Y-90 microspheres for colorectal cancer that has spread to the liver.4 The treatment offers hope for patients who have one or more colorectal liver tumors which cannot be treated by surgical resection or ablation.
Can you describe the procedure?
Using the liver’s unique blood supply, millions of tiny resin microspheres loaded with Yttrium-90 (Y-90) are released into the liver blood circulation. The radioactive microspheres lodge in the blood supply of the tumor, where they emit radiation for about two weeks.The treatment normally takes about 60 to 90 minutes, with most patients returning home four to six hours later. Patients are carefully monitored throughout and after the procedure. The most commonly reported side effects are flu-like symptoms over one to three weeks. The procedure can be performed in combination with chemotherapy or by itself.
Where is the procedure performed?
The procedure is performed at a hospital or clinic on an outpatient basis by highly trained physicians called interventional radiologists.
How effective is it?
Clinical studies have shown that SIRT with SIR-Spheres microspheres increases the length of time that the cancer is stable and not growing without adversely affecting the patient’s quality of life. In clinical studies, the SIRT procedure has been combined with chemotherapy, given as a single procedure during a chemotherapy holiday or after chemotherapy options have failed.