With an equal rate of incidence and mortality-the number of those who get it, and the number of those who die from it-Glioblastoma Multiforme (GBM) is a brain cancer death sentence.
Of the approximately 12,000 people who are diagnosed with GBM annually in the U.S., half will die within a year, and the rest within 3 years. Currently, the only treatments that stretch survival limits are exceptionally invasive surgeries to remove the tumor and radiation treatment with the maximum tolerated dose - all of which leads to a painfully low quality of life. Because of this, researchers are racing to find better therapies to stop or slow GBM.
In the Jan. 1, 2006 issue of the journal Clinical Cancer Research, Gelsomina "Pupa" De Stasio, professor of physics at the University of Wisconsin-Madison, and her colleagues report on research into using a new radiotherapy technique for fighting GBM with the element gadolinium. The approach might some day lead to less invasive treatment and 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," says De Stasio. The therapy, called Gadolinium Synchrotron Stereotactic Radiotherapy (GdSSR), requires a gadolinium compound to find tumor cells and penetrate 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's known as "the photoelectric effect" takes place.
"Exactly 100 years after Einstein first explained this effect, we have found a way to make it useful in medicine," De Stasio says. "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."
De Stasio adds that, for the treatment to be effective, gadolinium must be absent from normal cells and be present in the majority of the cancer cell nuclei. The first condition is well demonstrated by MRI, while the second was recently demonstrated using microscopy techniques at the Synchrotron Radiation Center (SRC) in Stoughton.
De Stasio, the first to introduce this technique into the biological and medical fields, is working to develop the therapy to treat GBM. In the current article, she and her colleagues prove that gadolinium reaches more than 90 percent of the cancer cell nuclei, using four different kinds of human glioblastoma cells in culture.