Botox Tested on Stomach Cancer in Mice
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Researchers working with mice are using Botox to try to combat stomach cancer by silencing nerves that connect to tumors. The work is still in its very early stages, and a prominent cancer expert cautioned that the approach is far from ready for prime time.
While the study findings are intriguing and worth pursing, "it would be inappropriate to pursue this treatment outside of a clinical trial," said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. "Remember that this is a mouse experiment. These types of experiments have been done for decades, and the actual translation into benefiting patients is uncommon."
Stomach cancer, also known as gastric cancer, will kill an estimated 11,000 people in the United States this year, according to the National Cancer Institute.
It creates special challenges for treatment because it's generally "silent," Lichtenfeld said, explaining stomach cancer doesn't become noticeable until it's so advanced that patents require extensive surgery or chemotherapy.
While not one of the most common cancers in the United States, rising rates of obesity and reflux disease have boosted certain types of stomach cancer, Lichtenfeld said. Rates of stomach cancer are much higher in Southeast Asia and Japan.
Scientists think nerves are crucial to tumor growth, but the role they play isn't clear. In the new study, published in the Aug. 20 issue of Science Translational Medicine, researchers try to silence the nerves that connect to the stomach and seem to support tumors.
In mice with a rough equivalent of human stomach cancer, the researchers tried several approaches, including cutting nerves to the stomach or paralyzing them with injections of Botox.
"The nerves are silenced or muted, unable to signal to the stem cells and cancer stem cells in the stomach," said study co-author Dr. Timothy Wang, professor of medicine and chief of digestive and liver diseases at Columbia University Medical Center in New York City.
According to the study, the two treatments reduced the number of tumors and their progression while boosting survival and the effects of chemotherapy.
The findings show that "nerves are very important in the development and formation of many organ systems and likely play a very important role in the early growth and spread of tumors," Wang said.
Botox is made from a toxin produced by the bacterium Clostridium botulinum. It is best known for temporarily smoothing wrinkles by paralyzing facial muscles. Doctors also use it to correct crossed eyes, control excessive underarm sweating and overactive bladder, and to treat migraine headaches, according to the National Institutes of Health.
Wang acknowledged there are many caveats to the study. For one thing, silencing the nerves could hurt the functioning of the stomach, although some issues could be fixed. "In the setting of cancer all of these effects are probably minor," Wang said. Also, the treatment wouldn't help with cancer that has spread beyond the stomach, he said.
It's also not clear how much a possible Botox treatment would cost, although the toxin in Botox is fairly cheap compared to the cost of many cancer drugs, he said, and has few side effects. The Botox would be administered through gastroscopy, a noninvasive procedure, and require a hospital stay of a few hours, the researchers said.
Wang said researchers are now testing their approaches in patients in clinical trials. However, Lichtenfeld cautioned that the approach's "impact on cancer treatment remains far from certain."
Results obtained from animal studies are not necessarily replicated in humans. "This would have to be applied in patients before anyone could make any claim about the benefit," Lichtenfeld said.
SOURCES: Timothy Wang, M.D., professor, medicine, and chief, digestive and liver diseases, Columbia University Medical Center, New York City; Len Lichtenfeld, M.D., deputy chief medical officer, American Cancer Society, Atlanta, Ga.; Aug. 20, 2014, Science Translational Medicine