A controlled fasting period lasting no more than 48 hours improved the effectiveness of chemotherapy and radiation therapy in mice with gliomas.
Gliomas, including anaplastic astrocytoma and glioblastoma multiforme (GBM), account for more than 50% of all primary brain tumors, noted Valter D. Longo, director of the Longevity Institute at the University of Southern California, Davis, School of Gerontology, and colleagues in PLoS One. GBM, the most common malignant brain tumor in adults, is highly invasive and angiogenic; it is associated with a median survival of 12 to 15 months.
In previous research, Longo’s team showed that short-term fasting made cancer cells vulnerable to the toxic effects of chemotherapy while protecting healthy cells. In the new study, the investigators tested the effect of starvation on glioma cells by depriving mice of food for 48 hours prior to radiotherapy or prior to chemotherapy with temozolomide, the standard therapeutic agent used after attempted surgical resection of glioma.
The 48-hour fast caused a significant reduction in blood glucose and circulating insulin-like growth factor 1 (IGF-1) levels, and sensitized both subcutaneous and intracranial glioma models to radiotherapy and chemotherapy. Compared with mice that underwent fasting alone or radiation alone, more than twice as many mice receiving both interventions survived to the end of the trial period. In terms of chemotherapy, the greatest effect in decreasing tumor progression was observed when starvation was combined with temozolomide therapy for two consecutive treatment cycles.