September Spotlight — Radiology: Selective Internal Radiation Therapy (SIRT): Advanced Treatments for Patients with Hepatocellular Carcinoma and Metastatic Colorectal Carcinoma


Submitted by Peter Villas, MD. PhD, Interventional Radiology, Main Line Health System.

Selective Internal Radiation Therapy (SIRT) is a treatment for primary liver cancers or certain tumors that have spread to the liver such as colon cancer.  The treatment delivers millions of tiny radioactive microspheres or beads directly to the liver tumors. There are two products: SIR-Spheres® and TheraSphere®.


Both products are about one third the diameter of a strand of hair in size and they release a type of radiation energy called ‘Beta’ radiation. Beta radiation is a common type of radiation used in other nuclear medicine therapy and diagnostic procedures.  These products are approved for the treatment of liver tumors that cannot be removed by surgery or treated percutaneously using ablative techniques such as microwave, cryo and/or radiofrequency ablation.


To perform SIRT, a small incision is made in the groin and a small thin catheter is placed in the artery and guided into the liver. The beads are delivered through the catheter and are then carried by the bloodstream directly to the tumor(s) in the liver.  The majority of beads are lodged in the tumors.  The radiation has a direct destructive effect on the tumor itself, destroying the tumor cells from within, with minimal impact to the surrounding healthy liver tissue.  Additional damage to the vessels feeding the tumor results in blocking nutrients in the bloodstream from reaching the tumor. Most patients after SIRT will see a reduction or stabilization of their liver tumor(s).


For most patients, treatment will result in increased survival time, but not a permanent cure.  In those patients with primary liver cancer the goal is to not only control of the tumor, but facilitation of the liver transplant process.


There are two questions patients often ask when discussing treatment options for their cancer. One is, “how bad are the side effects?” The other is, “will I need to be hospitalized for the procedure?” Both products are administered as an outpatient. Patients remain conscious throughout the procedure and almost always go home the same day. The radioactive microspheres continue to emit radiation over the course of several weeks after treatment and radiation levels will decrease to insignificant levels. Typical reported side effects are mild to moderate. These include abdominal pain and fatigue similar to having the flu, and symptoms usually dissipate within 48-72 hours.


Main Line Health System (MLHS) is proud to offer TheraSphere® and SIR-Sphere® treatment options. For more information, please contact a campus MLHS Interventional Radiologist.  My contact information is: Peter A. Villas, MD PhD // // 484-476-2826.


Example of Selective Internal Radiation Therapy Utilizing Therasphere.

– Patient with a large hepatocellular cancer demonstrating significant tumor response.


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