What is Y90 Radioembolization (SIRT)?
Radioembolization, also known as selective internal radiation therapy (SIRT), is a form of internal radiation therapy used in selected patients who are not candidates for surgery or percutaneous ablation of their liver tumor or tumors.
Beads coated with yttrium-90 (Y90) are delivered to the tumors in the liver through the arteries supplying the liver. Y90 is a beta-emitting radionuclide that acts locally at the tumor site. The beta particles emitted travel up to 11 mm in the liver. This allows the beads to irradiate the tumor while sparing healthy liver tissue. Additionally, given the low distance it travels, there are minimal, if any, necessary radiation safety precautions following treatment.
These radioactive microspheres target liver tumors by taking advantage of the increased arterial blood flow to the tumors. Normal liver tissue, on the other hand, is predominantly fed by the portal vein.
What type of tumors are treated with SIRT?
Radioembolization is currently used by interventional radiologists to treat primary liver cancer and metastatic cancer to the liver. The most common type of cancer being treated for this is colorectal cancer; however, it may also be used for breast, pancreatic, neuroendocrine tumors, and others.
How should I prepare for the SIRT procedure?
Before the procedure, you may have blood tested to determine how well your kidneys and your blood clotting are functioning. You should inform your doctor of all medications you are taking, including any herbal supplements. Inform us of any allergies, particularly to local or general anesthetic medications or to contrast materials (sometimes called X-ray dye) or to latex gloves. Always inform your doctor if you are or may be pregnant.
Eat a light meal the evening before. You will be instructed not to eat or drink after midnight before the procedure, and if you are diabetic you should receive instructions from your doctor about adjusting medications and insulin dose on the day of the procedure. You will be asked to remove your clothing and wear a gown during the procedure. You will also need a ride home with a friend or relative.
How is SIRT performed?
The SIR-Spheres microspheres treatment is performed as an outpatient procedure by specially trained physicians called interventional radiologists. During the procedure, the radiologist inserts a catheter into the artery in the groin and guides it to the arteries supplying the liver using live X-ray. The radioactive particles are then administered to the area of the tumor.
Once the beads are administered, the therapeutic dose of radiation is delivered over a period of 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.
After the procedure, you will be placed on bed-rest for two to six hours after the procedure. Most patients are discharged home the same day.
How effective is SIRT treatment and are there any side effects?
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 several 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. These patients have demonstrated increased survival and longer time to disease progression.
Overall the treatment is very well tolerated with minimal side effects. The most common side effect is fatigue, which can last two to four weeks.
In rare instances, a small number of microspheres may inadvertently reach other organs in the body, such as the gallbladder, stomach, intestine, or pancreas. If microspheres reach these organs, they can cause inflammation or ulceration. These complications are rare, but if they do occur they will require additional medical treatment. These complications are often avoided by performing a procedure prior to radioembolization that identifies and blocks arteries to these other organs, preventing the microspheres from reaching them.
Do patients have to take special precautions and when will I recieve the results?
There are some simple precautions that patients need to take during the first 24 hours following the SIRT procedure. These precautions include: thorough hand washing after using the toilet: and cleaning up any spills of body fluids such as blood, urine or stools and disposing of them in the toilet. Otherwise, patients can resume normal contact with family members.
The interventional radiologist will be able to inform you whether the procedure was technically successful. Your oncologist will order follow-up imaging to determine the clinical success of the procedure and whether or not additional procedures or treatments may be necessary.
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