Fasting Makes Brain Tumors More Susceptible to Radiation Therapy

A new study is the first to show that controlled fasting improves the effectiveness of radiation therapy in cancer treatments, increasing life expectancy in mice with aggressive brain tumors.

Earlier research conducted by University of Southern California (USC; Los Angeles, USA) professor of gerontology and biological sciences Dr. Valter Longo, corresponding author on the study and director of the Longevity Institute at the USC Davis School of Gerontology, has shown that short-term fasting protects healthy cells while leaving cancer cells vulnerable to the toxic effects of chemotherapy.

The latest study, which was published September 2012 in the online journal PLoS ONE, is the first to demonstrate that periods of fasting appear to have the same boosting effect on radiation therapy in treating gliomas, the most typically diagnosed brain tumor. Gliomas have a median survival of less than two years.

“With our initial research on chemotherapy, we looked at how to protect patients against toxicity. With this research on radiation, we’re asking, what are the conditions that make cancer most susceptible to treatment? How can we replicate the conditions that are least hospitable to cancer?” Dr. Longo questioned.

Dr. Longo and his coinvestigators, including Dr. Thomas Chen, codirector of the USC Norris neuro-oncology program, examined the combination of fasting with radiation therapy and with the chemotherapy drug Temozolomide, currently the standard treatment for the treatment of brain tumors in adults after an attempt at surgical removal.

The researchers discovered that controlled short-term fasting in mice, no more than 48 hours each cycle, improved the effectiveness of radiation and chemotherapy in treating gliomas. In spite of the extremely aggressive growth of the type of brain tumor studied, more than twice as many mice that fasted and received radiation therapy survived to the end of the trial period than survived with radiation alone or fasting alone.

“The results demonstrate the beneficial role of fasting in gliomas and their treatment with standard chemotherapy and radiotherapy,” the researchers wrote in their article. They noted that the findings indicated the benefits of short-term, controlled fasting for humans receiving treatment for brain tumors.

Dr. Longo cautioned that patients should consult with their oncologist before undertaking any fasting. “You want to balance the risks. You have to do it right. But if the conditions are such that you’ve run out of options, short-term fasting may represent an important possibility for patients.”

USC Norris Cancer Center, Mayo Clinic (Rochester, MN, USA), and Leiden University Hospital (The Netherlands) are all conducting clinical trials on fasting and chemotherapy. A clinical trial on glioma, fasting, and radiotherapy is being considered at USC.

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