Radioisotope therapy involves the administration of radioactive compounds into the blood stream the target a patient’s cancer. This is usually achieved by attaching a radioactive compound to another compound that is capable of ‘seeking out’ the cancer cell. This allows for the delivery of the radioactive compound to exactly where the cancer cell is in the body. A considerable amount of research is being done to allow us to target radiation in this fashion. The most recent work is on the use of antibodies directed against cancer cells and ‘tagging’ these antibodies with a radioisotope.
Zevalin (ibritumomab tiuxetan) is one such agent used in the treatment of some patients with particular types of lymphomas. Zevalin binds yttrium-90 (Y-90) to an antibody against CD-20 (a protein commonly found on the surface of lymphoma cells) to target and kill the lymphoma cells.
Quadramet (Samarium Sm-153 lexidronam) is another agent that tags a radioisotope (Sm-153) to a molecule which preferentially goes to areas of bone turnover. This is a commonly used radioisotope therapy for patients with many painful areas of cancer in their bones.
Radioisotopes used in clinical practice are often very well tolerated and very effective. They are usually removed by the body via the kidneys pose no harm to people around the patient after they are administered.
Prior to the administration of a radioisotope therapy, you will meet with a radiation oncologist to discuss if you are a candidate for the treatment, what other tests or scans you may need prior to the therapy and what the risks and benefits of the treatment may be.