Selective internal radiotherapy (SIRT) is a treatment option for patients with primary and secondary liver malignancies. This technique involves the injection of radionuclides directly into the liver artery. If yttrium-90 is used, small particles the so called microspheres are used to deliver the radioactive substance. Two yttrium-90 products are commercially available: resin-microspheres (SIR-Spheres®) and glass microspheres (TheraSphere®). Due to differing blood supply of healthy liver tissue and tumour, the microspheres lodge directly in the tumour and can deliver radiation predominantly to the tumour.
In this review, the efficacy and safety of SIRT was assessed for the treatment of hepatocellular carcinoma (HCC) and for liver metastases of colorectal carcinomas (mCRC), the two most common indications.
2 studies, both reporting on TheraSphere®, were included for efficacy of SIRT for the treatment of HCC. The overall quality of evidence was, according to the GRADE approach, ranked as “very low”. For efficacy of SIRT for mCRC, 3 randomized controlled trials, all using SIR-Spheres®, were included but a judgment on efficacy was hampered as results deviated, different comparators were used and additional therapies were allowed.
Data on safety was considered in 8 studies overall. It seems that careful patient selection is crucial for a safe treatment with SIRT. Overall, the safety profile of this intervention is acceptable.
Based on the evidence identified, the inclusion of TheraSphere® for the treatment of HCC in the catalogue of benefits was not currently recommended. The evidence for the treatment of mCRC with SIR-Spheres® indicated that is more efficacious and as safe as other treatment options. An inclusion in the catalogue of benefits was therefore recommended with restrictions.