Aug. 26, 2002 -- Caffeine may protect against a common form of
Aug. 26, 2002 -- Caffeine may protect against a common form of skin cancer. Mouse studies suggest that caffeine might prevent youthful sunburns from causing tumors in older age.
"We may have found a safe and effective way of preventing skin cancer," says study leader Allan H. Conney, PhD, director of the laboratory for cancer research at Rutgers University College of Pharmacy.
The study, reported in the current early edition of the Proceedings of the National Academy of Sciences, used caffeine applied directly to the skin. The effect on mice exposed to ultraviolet radiation was dramatic. Treatment with caffeine reduced cancerous tumors by 72%. It reduced noncancerous tumors by 44%.
"What needs to be done now is a clinical research study to see if caffeine or [other] tea extracts can prevent cancer in humans," Conney tells WebMD. "We are very interested in looking in humans to see whether caffeine can have a protective effect in people who have already had squamous-cell carcinomas removed. These people are at high risk of having additional skin cancers."
The treatment would prevent squamous-cell carcinoma. These common skin cancers often appear in older people who spent too much time in the sun in their youth. If caught in time, surgery is nearly always successful. The caffeine study does not address the more serious issue of melanoma, the most dangerous kind of skin cancer.
Conney found that another chemical from green tea -- epigallocatechin gallate or EGCG -- prevented cancer. It didn't work quite as well as caffeine. As EGCG isn't a very stable compound, it would be more difficult to make into a topical treatment.
Much more work still needs to be done. Conney isn't yet sure how large a dose would be needed for an effect in humans. And he still needs to invent a formulation that people can use. However, he's pretty sure that just drinking more tea or coffee to prevent cancer isn't a good idea. The doses needed for an anticancer effect would be too large.
Why did caffeine kill the cancer cells? Conney and colleagues found evidence that caffeine somehow triggers tumor cells' built-in self-destruct mechanism. That makes a lot of sense to Joel S Bedford, PhD, professor of radiological health science at Colorado State University, Fort Collins. Bedford has studied interactions between caffeine and radiation.
"If caffeine enhanced the body's own killing effect, then you could reduce the tumor-development process," Bedford tells WebMD.
Adil Daud, MD, is a skin-cancer expert at Moffitt Cancer Center in Tampa, Fla. He reviewed the Conney team's study for WebMD. Daud notes that caffeine treatment did not completely prevent skin cancers in mice.
"It is not a really super good preventative," Daud says. "A problem with skin cancer is that it is hard to convince people that they have to both put on sun block and avoid sun exposure. It is not a good thing for people to think that if they drink tea they can be out in the sun more. I think the point of this study is that caffeine may work against a kind of skin cancer that is not as deadly as melanoma. Squamous-cell cancers are bad, but as long as we can take them out, they will not recur. Melanomas are the real problem."
