Radioactive isotopes, also known as radioisotopes, are used in cancer treatment because they emit radiation that can kill cancer cells by damaging their DNA. This targeted approach allows doctors to deliver radiation directly to cancer cells while minimizing harm to surrounding healthy tissue. Several types of cancer can be treated effectively with radioactive isotopes, often through a method called radiopharmaceutical therapy or targeted radionuclide therapy.
One of the most common uses of radioactive isotopes is in **prostate cancer**, especially when it has spread to the bones or is metastatic. For prostate cancer that has metastasized to the bones, a radioactive isotope called Radium-223 (marketed as Xofigo) is used. Radium-223 mimics calcium and naturally targets bone tissue, particularly areas damaged by cancer, delivering alpha particle radiation that kills cancer cells in the bone while sparing most healthy tissue. Another treatment for metastatic prostate cancer uses Lutetium-177 linked to a molecule that targets a protein called PSMA (prostate-specific membrane antigen) found on prostate cancer cells. This treatment, known as Pluvicto, delivers beta radiation directly to the cancer cells, helping to control the disease when other treatments have failed.
**Neuroendocrine tumors** are another group of cancers treated with radioactive isotopes. These tumors often have receptors for a hormone-like substance called somatostatin. Lutetium-177 dotatate (Lutathera) is a radiopharmaceutical that binds to these somatostatin receptors, delivering targeted radiation to the tumor cells. This therapy is used for advanced neuroendocrine tumors, including those originating in the pancreas and gastrointestinal tract.
**Lymphomas**, which are cancers of the lymphatic system, can also be treated with radioactive isotopes. Yttrium-90, a beta-emitting isotope, is used in combination with a monoclonal antibody called ibritumomab tiuxetan (Zevalin). This antibody targets the CD20 protein on lymphoma cells, delivering radiation directly to them and sparing most normal cells. This approach is particularly useful for certain types of non-Hodgkin lymphoma.
**Thyroid cancer** and some thyroid conditions like hyperthyroidism are treated with radioactive iodine (Iodine-131). The thyroid gland naturally absorbs iodine, so when radioactive iodine is administered, it concentrates in thyroid cells, including cancerous ones, and destroys them with beta radiation. This treatment has been a standard for decades and is highly effective for many thyroid cancers.
Beyond these established uses, research and clinical trials are expanding the role of radioactive isotopes in treating other cancers. For example, theranostics—a combination of therapy and diagnostics—uses radioactive isotopes attached to molecules that seek out specific targets on cancer cells. This approach is being explored for cancers such as breast cancer, brain tumors, kidney cancer, melanoma, pancreatic cancer, and more. New targets like the DLL3 protein found in some aggressive neuroendocrine cancers are being investigated, with promising early results.
Different types of radiation emitted by isotopes—such as alpha particles, beta particles, and sometimes gamma rays—have varying properties. Alpha particles have high energy but travel only a short distance, making them ideal for killing cancer cells with minimal damage to nearby healthy tissue. Beta particles travel farther and can be useful for treating larger or more diffuse tumors. The choice of isotope and radiation type depends on the cancer type, location, and treatment goals.
In summary, radioactive isotopes are used to treat a variety of cancers, including:
– Prostate cancer (especially metastatic and bone-involved)
– Neuroendocrine tumors
– Lymphomas
– Thyroid cancer and hyperthyroidism
Emerging research is expanding their use to other cancers, leveraging the precision of targeted radiopharmaceuticals to improve outcomes while reducing side effects. This fiel
