Mar. 2--Arizona Cancer Center researchers will study women with cervical infections to look for evidence that green tea plays a role in cancer prevention.

The clinical study, sponsored by the National Cancer Institute's Division of Cancer Prevention, will examine the effects of green tea extract on women with various persistent cervical infections, including human papillomavirus -- HPV, which can cause cervical cancer.

Researchers are in the midst of recruiting 160 women in Arizona, California and North Carolina and expect to have some results in about a year.

Ideally, the study would help in the development of a drug for such women to clear the disease and prevent them from developing cervical cancer, said Dr. Francisco Garcia, an associate professor of obstetrics and gynecology at the University of Arizona's College of Medicine and one of the study's principal investigators.

"Because HPV is such a common infection and because a significant number of reproductive-age women develop precancerous infection, we hope we can come up with a drug to prevent us from taking off a piece of their cervix to cure them," Garcia said.

"The HPV vaccine is really a positive thing. However, if you are already sexually active and been exposed, it's not going to do anything for you. We want to do something for that group of women that is already sexually active and not young enough to receive the vaccine."

Researchers say green tea could have the effect of making HPV-infected cells self-destruct.

"Our basic science work, at least in the laboratory, is very interesting and compelling," Garcia said. "Green tea has been tried for other advanced cancers to help keep it at bay, so all the information together makes this very intriguing."

Green tea is often touted as a way of reducing and preventing cancer in humans, but researchers say more scientific studies are needed to determine whether that's true.

The Arizona Cancer Center study will investigate the effects of the decaffeinated, catechin-enriched green tea extract Polyphenon E. Catechins are plant chemicals that are considered powerful anti-oxidants, and researchers say they have multiple beneficial biological effects that could lead to cancer prevention.

The study will recruit women who have had a diagnosis of persistent cervical infection for at least six to 12 months. Eligible participants will take either 800 mg capsules of Polyphenon E (green tea extract) -- the equivalent of about 16 cups of green tea -- or a matched placebo for four months.

Monthly clinic visits will include review of compliance and any side effects, and blood tests for liver function. The final evaluation will include a tissue sample from the cervix.

Approximately 20 million Americans are currently infected with HPV, and another 6.2 million become newly infected each year.

The American Cancer Society estimates that about 11,070 women were diagnosed with cervical cancer in the United States in 2008.

volunteers still needed

Women over the age of 18 who have a cervical infection are invited to call 626-8539 to enroll in the study.

Green Tea Facts

Made from the steamed and dried leaves of the camellia sinesis plant, which is a shrub native to Asia. Black tea is also made from this plant, but unlike green tea it is made from leaves that have been fermented. Fermentation may reduce the levels of some compounds, such as anti-oxidants.

History: The Chinese have been drinking green tea for at least 3,000 years. In recent years, scientists have begun to study its health effects in lab animals and in observational human studies.

Possible health effects: Some reports indicate green tea may have the ability to help prevent cancers of the skin, esophagus, stomach, colon, pancreas, lung, bladder, prostate and breast.

Evidence: Many lab studies in cell cultures and animals have shown green tea has activity against cancer cells. Studies in humans, however, have been mixed. At this time, the consensus of available scientific evidence does not support claims that green tea can help prevent or treat any specific type of cancer in humans. Controlled, randomized clinical trials are needed to determine its effectiveness.

Source: The American Cancer Society

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