Fasting Before Chemo Protects Healthy Cells

Mice starved for 60 hours were exposed to even higher chemo doses. At that level, all non-starved mice died by the fifth day, at which point all the starved mice continued to survive. Again, almost all starvation weight loss was regained post treatment, and no signs of toxicity were evident.

Longo and his colleagues concluded that short-term starvation does appear to guard healthy cells and allow cancer treatment to attack only diseased cells. They said they are now organizing a human trial.

"We hope this works with patients, and we have reason to think it will," he said. "I think I'm more enthusiastic about this than anything else I've done. And you can see the potential for this being turned into something very, very useful. But we won't know until we do it."

Dwayne Stupack, an assistant professor of pathology with the Moores Cancer Center at the University of California, San Diego, described the current effort as a "reasonable" approach toward mitigating the undesirable effects of chemotherapy.

"We all know that people can go for a few days without eating, and it's not going to kill them, because the cells in our body are able to adjust and make do," he noted. "It's an intrinsic evolutionary stress response that is designed to keep those cells alive. And it turns out that this response also works to keep those healthy cells alive during chemotherapy."

"So, I think what they've done is very interesting and exciting, in the sense that the tumor they looked at is very aggressive, very lethal, and they were able to use what I would call relatively high chemotherapy without causing toxicity -- because the cells have already been conditioned to sort of shut down," Stupack said.

Stupack cautioned, however, that the starvation technique might not work for everyone. "There are certain tumors that may already be altering metabolism to normal tissue, and certain populations of cancer patients among whom an intrinsic stress response to the cancer is already under way," he noted. "In these cases, this approach might not achieve anything further. Those are the kinds of limitations that should be considered."

More information

For more on chemotherapy treatment, visit the American Cancer Society.

SOURCES: Valter D. Longo, Ph.D., associate professor, biological sciences, Leonard Davis School of Gerontology, and Norris Cancer Center, University of Southern California, Los Angeles; Dwayne Stupack, Ph.D., assistant professor, pathology, Moores Cancer Center, University of California at San Diego; March 31, 2008,Proceedings of the National Academy of Sciences, online