Selective Internal Radiation Therapy (SIRT) using Yttrium-90 Microspheres (SIR-spheres)
Patient information by SIRTEX
Clinician information by SIRTEX
Your oncologist has recommended that you have treatment with SIR-Spheres. Please read this and the SIRTex pamphlet and discuss with your family. Bring this along with you when you come to see us to discuss further queries.
Please ring 9473 8728, ask to book an appointment for “SIR-sphere consult”.
Please bring with you the relevant scans, especially the latest CT scan of your liver.
What is SIRT?
Selective Internal Radiation Therapy (SIRT) is a therapy targeting the cancers in the liver.It uses SIR-Spheres, an Australian innovation which combine radioactive isotope (Y-90) with tiny particles (approximately 1/3 diameter of hair). These particles are lodged in the small blood vessels of your liver especially inside the tumour, and the isotope delivers localized high dose radiotherapy to kill the cancer cells.
This treatment can be used when liver tumours are not suitable for surgery or ablation, and chemotherapy alone might not be effective.
Usually a single treatment is given. Multiple therapies can be used if required. The treatment is used to control liver tumours and is rarely curative.
What is involved in SIRT?
The work-up session. This is a day procedure in the radiology department. You will need to have a liver angiogram to work out the road-map, to block-off potential escape pathways to gut vessels, and to work-out correct SIR-Sphere dose. The interventional radiologist will place a catheter (small tube) into an artery in the groin, under local anaesthetic. This catheter will be advanced inside the artery up into the liver. Detailed angiograms (road-maps) of the liver are obtained. Unwanted non-target arteries branching towards the stomach and duodenum are embolised (blocked off) with tiny metallic coils. This is done to prevent radioactive particles damaging the stomach and duodenum. Then you will receive an injection of 99mTc-MAA (a dummy radioactive tracer) into the catheter, to work out shunting to the lungs. When the catheter is removed from your groin, firm pressure will be applied for approximately 10 minutes. For approximately 2-4 hours, you will be asked to lie flat to avoid bleeding from the groin. In this time, we will take some pictures of your chest and abdomen with a gamma camera, which can measure the distribution of the dummy radioactive tracer. You will be able to go home on the same day. We will contact you regarding the date and time of the SIR-sphere implantation session. This usually occurs within the next 3 weeks.
Approximately 1 week before the SIR-Sphere implantation, we will ask you to commence Somac (proton pump inhibitor) to help protect your stomach. This should be continued for 5 weeks post-implantation.
The actual SIR-sphere implantation session. You will be admitted to SAN radiology to have the procedure, and then transferred to a ward for 1-2 night post-procedure observation.
The procedure is very similar to the work-up angiogram, but you will be given SIR-Spheres rather than the dummy tracer.
Am I radioactive to other people?
SIR-Sphere particles give the liver tumour a local dose of radiotherapy. The radiation travels less than 2.5mm inside liver; therefore very little radiation will leave your body. It has a half-life of 64 hours and effectively gone after 2 weeks. In the first week you should not to have prolonged close contact with children and pregnant women.
What are the complications and side effects?
Angiograms: some discomfort at the groin is very common, even when local anaesthetic is used. There may be bleeding from the groin or bruising after the procedure. Occasionally, these bruises can be large and can cause problems. Serious damage to the main leg vessel, or other blood vessels (eg false aneurysm, dissection, rupture) is very rare. Allergic reactions to the dye (iodinated contrast medium) or other agents used (eg local anaesthetic, antibiotics and other drugs) are uncommon but can be serious.Please let us know if you are allergic to iodine or any other substance.
Potential complications from the SIR-Spheres include:
Fever. Very common and can last for a week.
Fatigue and loss of appetite for 4 – 6 weeks are common (about ⅓ of patients).
Abdominal pain. May occur at the time of injection, and can be severe, requiring medications (eg morphine). This usually subsides over an hour or so, but some pain relief may be needed for several days.
Nausea and vomiting. Common, and may require medication.
Damage to other tissues. Gastritis (inflammation of the stomach), enteritis (inflammation of the bowel), hepatitis (liver inflammation) and liver failure , pnemonitis (lung inflammation) or pancreatitis (inflammation of the pancreas), are uncommon but may occur and maybe severe.
Serious complications are uncommon. You might experience some pain and fever, but it is unlikely that you will experience a severe or life-threatening complication.
Other forms of treatment such as radiotherapy or chemotherapy can also cause a range of mild, moderate, severe or life threatening complications.