Isotope astatine-211 To Prolong Lives Of Brain Tumor Patients

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In a study to determine safe dosages of the isotope astatine-211 for treating patients with recurring brain tumors, researchers were pleasantly surprised to find that not only was the isotope's potency sufficient to kill residual cancer cells without damaging sensitive healthy brain cells, but the patients experienced longer survival rates.

"Astatine-211 has as much as five times or more cell-killing efficiency than the standard treatments of external beam radiation or beta-particle injection," said Michael R. Zalutsky, professor of radiology and biomedical engineering at Duke University Medical Center in Durham, N.C. The ability to deliver such a potent cancer killer without causing neurotoxicity (damage to the delicate neurological system that controls brain function) would be a tremendous step forward in combating this lethal disease, he said.

In the past, surgeons have been able to remove the tumor bulk, Zalutsky added, but were unable to see and thereby identify any residual cancerous cells that had escaped into the margins of the healthy tissue surrounding the tumor. It is these cells, however, that continue to grow into new tumors and eventually kill the patient. Scientists have long believed that radioimmunotherapy (RIT) could be the best way to destroy these cells, but demonstrating the feasibility of delivering a sufficiently potent radioactive isotope without harming healthy brain tissue has been heretofore impossible.