Starving mice for a few days before chemotherapy protected their healthy cells from damaging side effects, offering a possible way to shield cancer patients from the debilitating hair loss, nausea and anemia that now plagues the treatments, researchers reported this week.
The study, published Tuesday in Proceedings of the National Academy of Sciences, could also allow the use of more potent chemotherapy doses without endangering patients.
Valter Longo, of the University of Southern California, who led the research, said healthy cells deprived of nourishment stop dividing and become more resistant to stress. That makes them less vulnerable to chemotherapy, which targets cells that are dividing.
Because cancer cells do not respond to their environment in a normal way, starvation does not protect them from the drugs, said Longo, who conducted the research with scientists at USC and Giannina Gaslini Institute in Genoa, Italy.
The experiment looked at how healthy and cancerous cells reacted when they were exposed to toxins after being denied glucose, a simple sugar. Yeast cells, for example, were 1,000 times more resistant to damage from chemotherapy than yeast cells containing a tumor gene.
An experiment in mice confirmed the protective effects of fasting. Of the 28 mice that received only water for 48 to 60 hours before chemotherapy, one died. By contrast, 20 of the 37 mice that did not fast died from treatment. All mice were given an amount of the cancer drug etoposide equivalent to three times the maximum human dose.
Fasting mice that survived treatment had no visible side effects, researchers said, compared with the second group of mice, which became sluggish and developed ruffled hair because of the drug.
Longo said colleagues at USC/Norris Comprehensive Cancer Center are planning a clinical trial to study the benefits of fasting in cancer patients taking chemotherapy drugs. The trial is expected to begin later in 2008, he said.
But Longo warned people with cancer that they should not fast before chemotherapy treatment without consulting their doctors because lack of food could be harmful to some patients.