Radiology advance points way to non-invasive brain cancer treatment

Glioblastoma Multiforme, GBM, is a brain cancer death sentence. It is the most lethal cancer there is.

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 treatments include highly invasive surgeries to remove the tumor and radiation treatment with the maximum tolerated dose, both leading to a very low quality of life. Hence, 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 use of a new radiotherapy technique to fight GBM with the element gadolinium. The approach might lead to less invasive treatments and that offer greater promise of alleviating the disease.

The therapy, called Gadolinium Synchrotron Stereotactic Radiotherapy (GdSSR), requires a gadolinium compound to find tumor cells and penetrate them, down to their nuclei, while sparing the normal brain. Then, the patient's head is irradiated with X-rays. The whole brain is transparent to X-rays, while gadolinium is opaque. Then, where gadolinium is localized—in the nuclei of the cancer cells only—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 highly destructive for DNA, but have a very short range of action.

Therefore, gadolinium atoms must be localized in the nuclei of cancer cells to induce DNA damage that the cancer cells cannot repair, and consequently cell death."

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.