Radio-embolization is very similar to chemoembolization but with the use of radioactive microspheres. This therapy is used to treat both primary and metastatic tumors. This treatment incorporates the radioactive isotope Yttrium-90 into the embolic spheres to deliver radiation directly to the tumor. Each sphere is about the size of five red blood cells in width. These beads are injected through a catheter from the groin into the artery supplying the tumor. The beads become lodged within the tumor vessels where they exert their local radiation that causes cell death. This technique allows for a higher, local dose of radiation to be used, without subjecting healthy tissue in the body to the radiation. The Yttrium-90 radiates from within and it can be viewed as 'internal' radiation. Radio-embolization is a palliative, not a curative, treatment. However, patients benefit by extending their lives and improving their quality of life. It is performed as an outpatient treatment. There are fewer side effects from this treatment compared to other cancer treatments. The main side effect being fatigue for 7-10 days.
What are Yttrium-90 Microspheres?
Microscopic radioactive polymer ‘beads’ are about 1/3 the size of a human hair. Millions of spheres, implanted via catheter, are delivered directly to the artery supplying blood to the tumor. Spheres become trapped in the tumor's vascular bed. The radio-isotope that emits beta radiation decreases over 14 days. The Interventional Radiologist typically treats one lobe at a time; the second lobe is treated 4-6 weeks after the first treatment.
Patient Benefits of Yttrium-90
• Improved quality of life and possibility of increased life expectancy
• Treats both primary and secondary liver cancers
• Minimally invasive outpatient procedure
• More potent dose delivered to tumor than traditional radiation therapy
• Regional treatment targets the tumors, leaving the healthy liver tissue relatively unaffected
• Radiation does not affect body's other organs
• Short recovery time
• Number and size of tumors in liver does not preclude treatment option
• Treats all tumors, including undetected tumors
• Results of a recent study of the overall survival of metastatic colorectal cancer cases show:
o 5.4 months without treatment
o 19.1 months with treatment
Patients who are candidates for Yttrium-90
• Inoperable metastatic colorectal cancer with liver as major disease site
• Evaluation by Interventional Radiologist to determine if patient meets selection criteria including:
o Sufficient remaining healthy liver with satisfactory function
o Rule out significant extrahepatic disease
o Liver's vasculature is acceptable to receive microspheres
Although it is not considered a cure, Yttrium-90 therapy has been shown to improve quality of life and prolong survival.