Selective internal radiation therapy

What is Selective Internal Radiation Therapy (SIRT)?

SIRT is a treatment for liver tumours that delivers millions of tiny radioactive microspheres or beads called SIR-Spheres® directly to the liver tumours.

SIR-Spheres® microspheres 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.

SIR-Spheres® are approved for the treatment of liver tumours that cannot be removed by surgery. These may be tumours that start in the liver (also known as primary liver cancer), or they may be tumours that have spread to the liver from another part of the body (also known as secondary liver cancer metastases).

What is involved with SIRT

You will normally have two procedures where you will be conscious (awake) but have some anaesthetic or sedation so you feel comfortable.

The first procedure for SIR-Spheres® is the preparation for the treatment commonly known as the “work up” that includes a radiology procedure known as an angiogram. The purpose of the angiogram or mapping is to prepare your liver for SIR-Spheres®. You do not need any special preparation for the angiogram. During the mapping procedure your interventional radiologist will block (embolise) specific vessels to minimise the potential for the SIR-Spheres® to travel to areas outside your liver (e.g. the stomach or intestine).

To perform the angiogram a small nick in the groin is made and the catheter is then inserted into the femoral artery (a large vessel in your leg). The catheter is then advanced into the specific area in the liver targeting the vessels supplying the liver tumours. During the positioning of the catheter a small amount of dye or contrast is infused through the catheter. The dye travels down the catheter into the liver and “lights” up the vessels. Images are taken throughout the procedure and it is painless. The procedure takes place in an angiography lab at the Mater Private Hospital Brisbane CardioVascular Unit. A local anaesthetic is given so that the discomfort from the procedure is minimal around the puncture wound. Spheres similar in size to SIR-Spheres® are then injected through the catheter. These Spheres are albumin (egg based) particles similar in size to the SIR-Spheres®. The purpose of injecting these spheres is to imitate the effect of the real SIR-Spheres® to determine their distribution in the liver and to minimise the possibility of the microspheres travelling to the lungs or other sites outside of the liver.

The second procedure for SIRT is identical to the “work up” except that SIR-Spheres® are infused rather than the Albumin particles in the first procedure. Depending on your recovery, you are usually in hospital for 1–2 days after your procedure.

Am I radioactive to other people?

SIR-Spheres give liver tumors a local dose of radiotherapy. The Beta radiation travels on average only 2.5 mm from the microspheres therefore very little radiation will be omitted from your body. In addition the half life (time that the dose reduces to half its value) is very short only 64 hours. After two weeks only around 2.5% of the original dose remains.

We do advise:

• not to sleep next to your partner in the first week after the SIR-Spheres procedure
• not to travel next to an individual for more than two hours in the first week after SIR-Spheres
• not to have close contact with children and pregnant women in the first week after your SIR-Spheres® treatment
• that adults can safely approach the patient for short periods of time. For prolonged periods they should be at least six feet away at all times for the first week.

What are the complications and side effects?

You may experience some or all of the following side effects or you may not experience any side effects at all.

Angiograms may cause:

• some discomfort at the groin is very common, even when local anaesthetic is used
• bruising
• bleeding
• trauma to artery in the groin
• false aneurysm, rupture and dissection are very rare buy may require surgery
• allergic reactions to the contrast dye.

Potential complications from SIR-Spheres® may include:

• pain in the abdomen that may last for a few hours. This can be well controlled with pain control medication
• nausea—this may be caused by the angiography dye that is injected into the vessels or as a result of the SIR-Spheres® infusion into the liver. This is a short term effect which can be well controlled with anti-nausea medication
• reduced appetite—some patients may feel a loss of appetite
• tiredness—this may be caused by the effect of the radiation on the liver tumours
• fever—the destruction of the liver tumours and the by products of this destruction may cause a short term fever. This can be well controlled with paracetamol or similar over the counter analgesics
• damage to other tissues. Gastritis (inflammation of the stomach), enteritis (inflammation of the bowel), hepatitis (liver inflammation), pancreatitis (inflammation of the pancrease) are uncommon but may occur and maybe severe.

Serious complications are uncommon. You may experience some pain and fever, but it is unlikely that you will experience a severe or life threatening complication.Most patients require a single night in hospital after treatment and you should be able to resume your normal daily activities within a few days.

What you may need to tell your doctor or nursing staff looking after you

• if you are pregnant
• If you have blood clotting problems
• If you are taking blood thinning medication (warfarin, aspirin, clopidogrel, anti-inflammatory).

You will be required to sign a consent form to say that the procedure has been explained to you fully, including risks and benefits. If you need any clarification please ask your doctor for more information before you sign.

Location and contact details

Mater Private CardioVascular Unit

Mater Private Hospital Brisbane
Level 6, 301 Vulture Street, South Brisbane, Queensland 4101

Telephone: 07 3163 6700
Bookings: 07 3163 1146 or 07 3163 1147
Facsimilie: 07 3163 6720

www.mater.org.au

© 2010 Mater Misericordiae Ltd. ACN 096 708 922

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