Earlier this month, researchers at the University of Southern California announced an important discovery. The scientists found a simple way to make certain kinds of tumors much more vulnerable to radiation therapy, in turn making treatment easier and more effective.
Glioblastoma multiforme, a kind of glioma, is the most common type of brain tumor. Half of all patients diagnosed with glioma survive less than two years. GBM strikes in star-shaped cells called astrocytes, and the tumors are marked by rapid growth. It is the most invasive type of glioma, generally spreading to different parts of the brain and sometimes even to other parts of the body.
Unfortunately, when gliomas appear at multiple locations, the already low long-term survival rates plummet. In one study, patients with multisite tumors survived an average of just six months. Indeed, sometimes the prognosis is so brief that state-of-the-art treatments cannot be used because there’s simply no time. There’s some evidence that these multisite tumors are resistant to treatment; it seems that the mechanisms by which they invade multiple sites also protect the tumors from medical attack.
Treatment for glioma usually starts with surgery, to remove the major portion of the tumor. In some cases, surgery is either deemed unnecessary or regarded as too dangerous. Whether or not surgery is indicated, radiation treatments and chemotherapy are used to shrink and eliminate tumors. The drug temozolomide has been used for almost 15 years in conjunction with radiation to treat several kinds of cancer, including glioma, with some success and with fewer adverse effects than older therapies.
One thing that makes radiation therapy more effective, the UC researchers discovered, is a brief period of controlled fasting immediately before the radiation. Mice with brain tumors who were not fed up to 48 hours before therapeutic doses of radiation had more than double the survival rate of mice fed normally. Studies have not been undertaken in humans but the researchers have suggested that it may be helpful as a last-ditch effort to boost the effectiveness of treatment.