First Use of Cesium-131 to Treat Prostate Cancer

In the first major innovation in brachytherapy in more than 15 years, physicians have for the first time implanted a new kind of radioactive seed in a prostate cancer patient.

The cesium-131 (Cs-131) brachytherapy implant seed was developed by IsoRay (Richland, WA, USA; www.isoray.com) and provides another practical alternative for men with prostate cancer. "The Cs-131 seed developed by IsoRay offers a shorter half-life and faster delivery of the total radiation dose than the other types of seeds currently on the market. We believe it will be an effective option for men choosing brachytherapy to treat their prostate cancer,” said Dr. Leroy Korb, assistant professor of radiation oncology at the University of Washington Medical Center (Seattle, WA, USA; www.uwmedicine.org), where the implantation procedure was performed.

The Cs-131 seed has a half-life of 9.7 days, compared to 60 days for the iodine-125 seed. It delivers more than 90% of its total radiation dose in less than 33 days. "The new Cs-131 seed has a significantly higher dose rate than iodine, allowing for the delivery of more radiation in a shorter period of time to maximize its effectiveness. The treatment is over in one-sixth the time of iodine seeds and leaves the body 500 days faster,” said Dr. Korb.

The investigators will implant the first Cs-131 seeds in a 74-year-old man; the procedure takes about 45 to 60 minutes. Needles are used to implant the seeds, which are smaller than a grain of rice. No incision or suturing is necessary, and it is typically an outpatient procedure. The patient is usually back to work and daily activities within two to three days. Because of the shorter duration of treatment with Cs-131, side effects may be lessened, such as urinary urgency, incontinence, or pain. In the University of Washington prostate cancer program, approximately 50% have chosen radiation treatment and the other 50% have chosen surgery. Out of the group that chose radiation, approximately 30% had external beam radiation and 20% had implanted seeds.

"We are very pleased to be the first to offer this new type of treatment at UV Medical Center, and to partner with IsoRay, a Washington-based company,” concluded Dr. Korb.





Related Links:
University of Washington Medical Center
IsoRay