Patient safety and clinical follow-up

Clinical Safety

Over 40,000 patient treatments of SIR-Spheres microspheres have been delivered worldwide. Within clinical studies conducted in more than 6,000 patients, SIR-Spheres microspheres have shown to have an acceptable safety profile.

This was confirmed in UK NICE Guidance issued on SIRT in July 2011, which stated that the "current evidence on the safety of selective internal radiation therapy (SIRT) for non-resectable colorectal metastases in the liver is adequate."¹ This was further reinforced by UK NICE Guidance issued on SIRT in July 2013 which stated that "current evidence on the efficacy and safety of selective internal radiation therapy (SIRT) for primary hepatocellular carcinoma is adequate for use..."²

Common Side effects

Patients may experience side effects from the procedure, but not all patients will get all of these.

The most common side effects are:

• Fatigue - this is the commonest side effect. It is usually mild, but it can last for 4-6 weeks.
• Mild fever - can last from a few days to a week and usually does not cause concern.
• Abdominal pain for a few hours after the procedure and sometimes several days. This will be controlled with simple painkillers.
• Nausea, usually mild and easily controlled with tablets.
• Diarrhoea, usually mild and not requiring treatment.
• Side Effects (less than 1 in 10 patients treated)

If a few microspheres reach the stomach or intestine, they may cause symptoms of indigestion, gastritis or abdominal discomfort similar to having a peptic ulcer. To prevent this from happening, patients are asked to take an anti-ulcer treatment once daily from the day of the the liver angiogram for a minimum of 8 weeks. Despite that, any symptoms of indigestion, reflux or upper abdominal pain developing up to 8 weeks from the SIRT procedure must be investigated in case there may be an underlying ulcer that requires treatment.

Rare Side Effects (less than 1 in 100 patients treated)

• Lung - if a few of the microspheres reach the lungs, patients may experience some shortness of breath and a cough 4-12 weeks after the treatment. This is very rare, but if it occurs, it may be treated with steroid tablets.
• Liver - radiation treatment to the liver may cause abnormalities in blood tests of liver function. This may appear 4-8 weeks after the treatment. Patients require regular blood tests to monitor liver function since this complication, 'radiation induced liver disease(RILD)', requires urgent intervention with high dose steroids. This rare side effect can be fatal in a small number of cases if it is not treated early enough. There is a guidance document from the FOXFIRE clinical trial which outlines what signs and blood results to look out for to detect this complication as early as possible, and how to treat it.
• Cholecystitis - inflammation of the gallbladder can result from the radiation, although this is a very rare complication. Normally this will resolve without treatment, but if it persists, it is may be necessary to remove the gall bladder in an operation 2-3 months after the microsphere treatment.

The potential long-term risk from these radiation doses is uncertain. However, as long as the radiation is confined to the liver, the side effects are usually mild. Any exposure to radiation has the potential for long-term damage, such as scarring of the liver or fluid accumulation within the abdomen. There is a theoretical risk of other malignancies developing many years later as a result of exposure to radiation, but this risk is small and cannot be quantified.

Clinical follow-up

On account of the risk of radiation complications, which are commonest 4-8 weeks from the treatment, patients should be seen in clinic regularly until 12 weeks from the SIRT procedure. Patients treated in the NHS Commissioning through Evaluation programme must be monitored every 3 months for clinical review and completion of quality of life questionnaires.

References:
^1. NICE. Guidance IPG401. Last updated May 2013.
^2. NICE. Guidance IPG460. July 2013.