New Treatment Option for Vertebral Cancer Metastases

Injecting radioactive bone cement into the vertebral body could offer a better treatment option than radiation therapy for breast cancer patients with metastasizes to their spines, according to a new study.

Researchers at the University of California Irvine (UCI, USA) and the St. Jude Heritage Medical Group (Fullerton, CA, USA) attempted to combine the two conventional treatment phases--surgery and external beam radiation therapy (EBRT)--for spinal cancer metastases into one procedure by mixing a radioactive compound with the injected cement. A single procedure using this radioactive bone cement would provide structural reinforcement to the bone while simultaneously irradiating the tumor from within (known as vertebral brachytherapy). Results of the study showed that a therapeutic dose of radiation would reach the intended bone without undue risk to tissue beyond a certain range, such as the spinal cord. Once the results have been validated, the researchers mean to refine the choice of radioisotopes, the amount of activity and geographic distribution of the cement, and define the sensitivity of the radiation dose distribution to variations in bone size, density, and tumor type, differences in bone cement formulations, and other factors associated with a potential clinical application. The study was presented at the 55th annual meeting of the Orthopedic Research Society, held during February 2009 in Las Vegas (NV, USA).

"With further development, this technology may yield a clinically feasible procedure that would eliminate the need for 10 radiation therapy sessions, making it more convenient for the patient,” said study presenter Joyce Keyak, Ph.D., an associate professor in the UCI department of orthopedic surgery. "This procedure would also deliver a higher dose to the bone metastases and a lower dose to the spinal cord and other normal tissues than conventional external beam radiation therapy, potentially improving the clinical outcome. The negligible dose to the spinal cord would also make it possible to treat recurrent spinal tumors in patients who have already received the maximum allowable radiation dose to the spinal cord.”

Spinal metastases can cause pain and vertebral collapse; and, due to the proximity of the spinal cord and nerves, those tumors can also lead to serious neurological complications. Conventional treatment often occurs in two phases: a surgical procedure--vertebroplasty or kyphoplasty--in which bone cement is injected into the body to stabilize the bone; and a subsequent EBRT to control tumor growth. The effectiveness of EBRT for spinal metastases is limited because the spinal cord restricts the dose of radiation that can be safely delivered. In addition, EBRT is typically provided in multiple sessions to reduce toxicity to the spinal cord, making treatment inconvenient for the patient.

Related Links:
University of California Irvine
St. Jude Heritage Medical Group