New Radiation Treats Prostate Cancer

[Angel]

Exposing cancer patients to unnecessary radiation is one of the drawbacks of using the therapy to treat tumors. Now, prostate cancer patients can choose a treatment that exposes them to less radiation.

A new isotope -- a radiation-emitting form of a chemical element -- is now available to treat prostate cancer. Cesium-131 was developed by IsoRay, a company based out of Richland, Washington. This isotope delivers more radiation in a shorter amount of time than other available isotopes.

Cesium-131 is packed into tiny titanium capsules that are about the size of a grain of rice. About 100 of these tiny seeds are implanted around the prostate tumor where they deliver radiation and destroy cancer cells. The radioactive seed technique is called brachytherapy and has been around for many years.

"The beauty of this technique for the prostate cancer patient -- they get their implant in a 45-minute procedure, they leave the clinic that day, and the next day can get back to a normal life," said David Swanberg, the executive vice president of IsoRay, today at the 48th Annual Meeting of The American Association of Physicists in Medicine.

Swanberg said new research has shown tumors respond to radiation treatment within the first 30 or 40 days, and that's why this treatment is even better with Cesium-131. Its half life is just 9.7 days, which means in 9.7 days, its radiation output is cut in half. That output is cut by half again every 9.7 days. In fact, 90 percent of the radiation dose is delivered in 33 days. So, the radiation leaves the patient's body quicker than with the radioactive isotopes used before now -- Palladium-103 and Iodine-125. Iodine-125 takes 204 days to deliver 90 percent of its radiation while Palladium-103 takes 58 days.

Right now, Cesium-131 is only available to treat prostate cancer. However, Swanberg said it could be used to treat cancers of the head, neck, breast, prostate and other organs. The company has not yet tested the treatment on those cancers in humans, however. "We need to make sure we can deliver this appropriately, and those are all things we are looking at right now," Lori Woods, vice president of IsoRay, said.