02 Jan Radiology advance points way to non-invasive brain-cancer treatment
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. 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 January 1, 2006, issue of the journal Clinical Cancer Research, Gelsomina “Pupa” De Stasio, professor of physics at the University of Wisconsin-Madison, and colleagues report on research into using a new radiotherapy technique for fighting GBM with the element gadolinium. The approach might lead to less invasive treatments that offer greater promise of alleviating the 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. To X-rays, 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.”
Because of the deadly nature of GBM, De Stasio says an alternative is desperately needed to current therapies. De Stasio says it will be a year before it is known whether the treatment works in animal models, and likely another five to ten years before any clinical trials and available treatments would emerge.
While the human health payoff seems far away, De Stasio says she is committed to the timetable needed for success. “(Fighting cancer) is the type of work that makes you feel good about being a scientist,” she says. “If you can really contribute to humanity and do something that’s useful for people, for sick people, it’s really incredibly gratifying.”