The initial work-up for staging provides essential information on the patient's well-being, liver status, as well as the extent and location of disease, which are used in the assessment of a patient's suitability for treatment.
Once identified as a potential candidate for SIRT by the multi-disciplinary team, patients are invited for further assessment, which includes a pre-treatment work-up:
- Hepatic angiogram (CT angiogram)
- Technetium-99m macroaggregated human albumin (Tc-99m-MAA) nuclear medicine SPECT scan
In parallel, a triple-phase contrast computed tomography (CT) and/or gadolinium-enhanced magnetic resonance imaging (MRI) of the liver should be conducted for assessment of tumour and non-tumour volume, portal vein patency, and extent of extrahepatic disease.
These assessments are essential for:
- confirming the appropriateness of the patient for treatment
- preparing the liver for Selective Internal Radiation Therapy (SIRT)
- planning the treatment procedure itself (either a whole liver or more selective approach)
- ensuring the optimum and safe delivery of SIR-Spheres® Y-90 resin microspheres to liver tumour(s), while limiting the impact of SIRT on healthy tissue
- calculating the appropriate activity of SIR-Spheres Y-90 resin microspheres to be administered
The treatment work-up includes a thorough angiographic evaluation of the liver vasculature to detect and occlude any vessels that could carry microspheres away from the liver to the stomach, duodenum, or gallbladder and to plan for the subsequent administration of SIR-Spheres Y-90 resin microspheres.
During this arteriography, the tip of the catheter is placed in the same position where the SIR-Spheres Y-90 resin microspheres will be delivered and the Tc-99m MAA is administered into the hepatic artery as a tracer to determine the extent of arteriovenous shunting to the lungs and to confirm the absence of gastric and duodenal flow.
Once the extent of extrahepatic shunting has been evaluated and the patient deemed acceptable for treatment, SIR-Spheres Y-90 resin microspheres will be administered at a subsequent visit. Some patients, however, may have vasculature that will preclude accurate and reliable placement of the catheter and therefore prohibit the safe delivery of the microspheres. The amount of lung shunting may alter the activity that can be safely implanted commensurate with acceptable risk of radiation pneumonitis. In such cases, the decision not to treat the patient may be taken.