New Radiotherapy Technique for Brain Cancer

Of the about 12,000 individuals who are diagnosed with glioblastoma multiforme (GBM), a type of brain cancer, yearly in the United States, 50% will die within one year, and the remainder within three years. Because of this, scientists are searching to find better therapies to stop or slow GBM.

At present, the only treatments that lengthen survival rates are very invasive surgeries to remove the tumor and radiation treatment with the maximum tolerated dose--all of which leads to a devastatingly low quality of life. In the January 1, 2006, issue of the journal Clinical Cancer Research, Dr. Gelsomina De Stasio, professor of physics at the University of Wisconsin-Madison (USA) and coworkers, reported on their study utilizing a new radiotherapy technique for combating GBM with the element gadolinium. This application may soon lead to less-invasive treatment and even possibly a cure of this disease.

"It's the most lethal cancer there is. The only good thing about it is that, if left untreated, death is relatively quick and pain-free, since this tumor does not form painful metastases in other parts of the body,” stated Dr. De Stasio. The therapy, called gadolinium synchrotron stereotactic radiotherapy (GdSSR), requires a gadolinium compound to find tumor cells and infiltrate them, down into their nuclei, while sparing the normal brain. Then, the patient's head is irradiated with x-rays. For these x-ray photons the whole brain is transparent, while gadolinium is opaque. Then, where gadolinium is localized--in the nuclei of the cancer cells only--what is known as "the photoelectric effect” occurs.

"Exactly 100 years after Einstein first explained this effect, we have found a way to make it useful in medicine,” Dr. De Stasio reported. "In this effect, atoms absorb photons and emit electrons. The emitted electrons are very destructive for DNA, but have a very short range of action. Therefore, to induce DNA damage that the cancer cells cannot repair, and consequently cell death, gadolinium atoms must be localized in the nuclei of cancer cells.”

Dr. De Stasio, the first to introduce this technique into the biologic and medical fields, is working to develop the therapy to treat GBM. In the current study, she and coworkers established that gadolinium reaches more than 90% of the cancer cell nuclei, using four different kinds of human glioblastoma cells in culture.

Dr. De Stasio developed and oversees the X-ray PhotoElectron Emission SpectroMicroscopy (X-PEEM) program at UW Madison's SRC, where she also serves as interim scientific director. The technology needed for eventual treatment would involve miniature synchrotron light sources, which could be similar in size and cost to an MRI machine.




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