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Selective Internal Radiation Therapy

Selective Internal Radiation Therapy (SIRT) is a treatment for advanced liver cancer that uses new technologies to deliver radiation directly to tumors. Conventional radiotherapy is only applied to limited areas of the body and can adversely affect nearby tissues. SIRT delivers millions of microscopic radioactive spheres, called SIR-Spheres®, directly to the liver tumors, where they selectively irradiate the tumors.

Because SIRT is highly targeted, doctors can deliver up to 40 times more radiation to the liver tumors than with conventional radiotherapy. 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.

How It Works

A catheter is inserted into the femoral artery and threaded through the major blood vessel of the liver (hepatic artery) to the tumor site. The SIR-Spheres are delivered through the catheter and trapped in the tumor, reducing its blood supply and radiating the cancer cells. The radiation is delivered over two weeks, at which point the microspheres are no longer radioactive.

Healthy liver tissue receives most of its blood from the portal vein, while tumors receive most of their blood supply from the hepatic artery. Inserting the catheter through the hepatic artery allows targeted administration of radiation to liver cancer.

Unlike chemotherapy, which is given in cycles, SIRT is typically administered to the patient in two separate treatments. One treatment is given to the right lobe of the liver and one to the left lobe, with the treatments occurring at least one month apart. The treatment is considered outpatient, and patients normally go home within 24 hours.

Patient Outcomes

SIRT is generally not considered to be a cure but has been shown to shrink liver cancer more when combined with chemotherapy than chemotherapy alone. This can increase a patient’s life expectancy and improve quality of life.

Occasionally, SIRT patients have a reduction in tumor size significant enough that the cancer can be surgically removed at a later date. This has resulted in a long-term cure for some patients.

Patients who are good candidates for SIRT, generally:

  • Have inoperable secondary (from colorectal primary) liver cancer.
  • Have the liver as the major site of the disease.
  • Have sufficient remaining healthy liver still functioning
  • Are well enough to tolerate the implant.
  • Meet the pre-selection criteria, as determined by their doctors’ pre-treatment testing.

SIRT is not suitable for patients who have:

  • Had previous external beam radiation therapy to the liver.
  • Ascites (fluid in the abdomen) or are in clinical liver failure.
  • Markedly abnormal synthetic and excretory liver function tests.
  • Tumors responsive to surgical resection for cure.
  • Greater than 20% lung shunting (determined by the nuclear medicine breakthrough scan).
  • Pre-assessment angiograms and MAA nuclear scans that demonstrate significant reflux of hepatic arterial blood to the stomach, pancreas or bowel.
  • Widely spread or extra-hepatic disease.
  • Been treated with oral chemotherapy within the previous two months, or who will be treated with it at any time following SIRT treatment.

What to Expect

Prior to appointments, patients are asked to come in for routine lab work. It is preferred that patients have their lab work performed at the hospital so the radiology nurses have access to the results. Our radiology nurses call each patient shortly after the procedure is scheduled to obtain a health history and provide instructions.

For most interventional radiology exams, patients need to arrive in admissions two hours before their scheduled procedure time on the day of the exam. Patients will check in at admissions before being taken to the Imaging Nursing Unit, where an interventional radiologist will come to talk with the patient before the procedure. The patient will then be prepped for the exam and taken to the Interventional Radiology Suite for the procedure. Following the procedure, the patient will return to the Imaging Nursing Unit for recovery. The recovery time varies based on the procedure. After the patient is then discharged, he or she will receive a follow-up call the next day.

Call 678-312-3444 to schedule an appointment at one of our convenient locations.