Selective Internal Radiation Therapy (SIRT)

Selective Internal Radiation Therapy (SIRT) Now Available at Meridian Cancer Care

If you or a loved one has been diagnosed with colorectal cancer that has spread (metastasized) to the liver, it is important to learn the facts and evaluate treatment options. Of the nearly 140,000 Americans diagnosed with colorectal cancer every year, at least 60 percent will see their cancer spread to the liver, and many will die of this disease.1, 2 A diagnosis of liver cancer can be overwhelming, but there is hope.

SIR-Spheres® microspheres treatment, offered at Meridian Cancer Care, is 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. SIR-Spheres microspheres are approved for patients with inoperable liver cancer. *

Who is a candidate for the treatment? 

This treatment is approved for patients with inoperable live cancer.


How are SIR-Spheres microspheres administered? 

SIR-Spheres 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.


How do SIR-Spheres 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 SIR-Spheres 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 SIR-Spheres microspheres different from other radiation treatments for cancers of the liver?

SIR-Spheres microspheres usually reduce liver tumors after just one treatment. The targeted nature of SIR-Spheres 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 SIR-Spheres microspheres. Another limitation of conventional radiotherapy is that it can only be applied to certain areas of the body, often not including the liver. SIR-Spheres microspheres, however, are designed specifically for delivery directly to the liver.


What are the goals of treatment using SIR-Spheres microspheres?

Clinical trials have shown SIRT increases the time-to-disease progression and overall survival without adversely affecting the patient’s quality of life. 3 In clinical studies, SIR-Spheres microspheres have been combined with modern chemotherapy or administered as a monotherapy during a chemotherapy holiday and have been proven to: 4, 5-11

  • Decrease the tumor burden in the liver 4, 5-9
  • Increase time-to-disease progression 5, 6
  • Increase survival time 3
  • Potentially downsize tumors to liver resection or ablation 5, 7,10,11 
  • 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 SIR-Spheres 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.

SIR-Spheres microspheres are only for the treatment of cancer which has spread to the liver.12 are the ONLY fully FDA-approved microsphere radiation therapy for the treatment of colorectal liver metastases.



1 Landis SH, Murray T, Bolden S, et al. Cancer Statistics. CA Cancer J Clin. 1999;49:8-31.

2 American Cancer Society. Cancer Facts & Figures, 2013. Atlanta, ACS, 2013: 5.

3 Seidensticker R, Denecke T, Kraus P, et al. Matched-pair comparison of radioembolization plus best supportive care versus best supportive care alone for chemotherapy refractory liver-dominant colorectal metastases. Cardiovasc Intervent Radiol. 2011 July 29. [Epub ahead of print]

4 Jakobs TF, Hoffman RT, Dehm K, et al. Hepatic yttrium-90 radioembolization of chemotherapy-refractory colorectal cancer liver metastases. J Vasc Interv Radiol. 2008;19(8):1187-1195.

5 Gray B, van Hazel G, Hope M, et al. Randomised trial of SIR-Spheres plus chemotherapy vs. chemotherapy alone for treating patients with liver metastases from primary large bowel cancer. Ann Oncol. 2001;12(12):1711–1720.

6 van Hazel G, Blackwell A, Anderson J, et al. Randomised phase 2 trial of SIR-Spheres plus fluorouracil/leucovorin chemotherapy versus fluorouracil/leucovorin chemotherapy alone in advanced colorectal cancer. J Surg Oncol. 2004;88(2):78–85.

7 Sharma R, van Hazel G, Morgan B, et al. Radioembolization of liver metastases from colorectal cancer using yttrium-90 microspheres with concomitant systemic oxaliplatin, fluorouracil, and leucovorin chemotherapy. J Clin Oncol. 2007;25(9):1099–1106.

8 van Hazel GA, Pavlakis N, Goldstein D, et al. Treatment of fluorouracil-refractory patients with liver metastases from colorectal cancer by using yttrium-90 resin microspheres plus concomitant systemic irinotecan chemotherapy. J Clin Oncol. 2009;27(25):4089–4095.

9 Kennedy A, Coldwell D, Nutting C, et al. Resin 90Y-microsphere brachytherapy for unresectable colorectal liver metastases: modern USA experience. International Journal of Radiation Oncology, Biology, and Physics. 2006;65(2):412-425.

10 Hoffman RT, Jakobs TF, Kubisch C, et al. Radiofrequency ablation after selective internal radiation therapy with Yttrium90 microspheres in metastatic liver disease—Is it feasible?. Eur J Radiol. 2010;74:199-205.

11 Whitney R, Tatum C, Hahl M, et al. Safety of hepatic resection in metastatic disease to the liver after yttrium-90 therapy. J Surg Res. 2011;166:236-240.

12 SIR-Spheres microspheres are indicated for the treatment of unresectable metastatic liver tumors from primary colorectal cancer with adjuvant intra-hepatic artery chemotherapy (IHAC) of FUDR (Floxuridine).

Wellness Resources

    • Cancer Health Library

      Cancer Health Library

      With information on everything from nutrition to genetics, a wealth of information awaits patients, survivors and their families here.

      Learn More
    • Take a Vacation from Cancer

      Take a Vacation from Cancer

      From time to time, you may benefit from taking a respite from your cancer diagnosis, even if you can't leave your illness completely behind.

      Learn More
    • Nutrition and Cancer Quiz

      Nutrition and Cancer Quiz

      What effect does diet have on your risk for cancer? Find out by taking this quiz, based in part on information from the American Cancer Society.

      Learn More

Related Services

    • CyberKnife

      CyberKnife Center

      The precision of the CyberKnife treatments reduce patients' radiation therapy sessions from as many as 40 to 5 or less.

      Learn More
    • Diagnostic Imaging

      Diagnostic Imaging

      Our imaging procedures use advanced imaging technology subject to stringent regulatory standards.

      Learn More
    • Surgery


      Meridian Health’s surgical teams of anesthesiologists, registered nurses and board certified, fellowship-trained surgeons work in state-of-the-art operating rooms.

      Learn More