Green Tea - New Hope For Leukemia Patients

By Margarita Nahapetyan

According to Mayo Clinic scientists, drinking green tea could be a new hope for thousands of leukemia patients. The experts claim that they have established a positive link between the chemical epigallocatechin gallate (EGCG), an active antioxidant ingredient in green tea, and a potential treatment of the disease.

Researchers have been examining the anti-cancer properties of green tea since the 70s, when one study found that those countries where green tea was consumed in large amounts, were likely to have lower levels of chronic lymphocytic leukemia (CLL) - the most common form of the disease. Currently, CLL has no cure. The disease starts with a mutation in a single blood cell called a lymphocyte. After some time, the altered cells multiply and replace normal lymphocytes in the bone marrow and lymph nodes, organs that are found all over the body and work by filtering foreign particles. As a result, the lymph nodes get larger in size. Statistics show that about half of patients with the disease at an early stage have an aggressive form of CLL that results in early death. Researchers hope the green tea extract can stabilize early stage patients or perhaps work in combination with other therapies in order to improve the effectiveness of treatment.

For the new study, the early stage clinical trial involved 33 patients with chronic lymphocytic leukemia who received variations of 8 different oral doses of Polyphenon E, a commercially produced green tea extract whose primary active ingredient is EGCG. Doses that ranged from 400 milligrams to 2,000 milligrams were given to patients two times a day. Scientists determined that the participants had not reached a maximum tolerated dose, even at 2,000 mg twice a day.

The trial revealed that participants with chronic lymphocytic leukemia could tolerate the chemical fairly well when high doses were given to them in a capsule form. And what is even more, lymphocyte count - a measurement that counts a number of white blood cells - was decreased in 30 per cent of the patients, indicating cancer regression.

"We found not only that patients tolerated the green tea extract at very high doses, but that many of them saw regression to some degree of their chronic lymphocytic leukemia," said Dr. Tait Shanafelt, M.D., hematologist at Mayo Clinic and a main investigator of the research. Dr. Shanafelt added that most patients who were enrolled in the trial with enlarged lymph nodes, demonstrated a 50 per cent or even more decline in the sizes of their lymph nodes.

The study has now moved to another phase of clinical testing in a follow-up second trial, which will include exactly the same number of participants. At this time, all individuals will be receiving the highest dose of Polyphenon E administered from the previous trial.

These clinical trials are the latest steps in a multiyear research that started with experiments that looked at the effect of the green tea extract on cancer cells in the laboratory of Mayo hematologist Dr. Neil Kay, M.D., a co-author of this report. After the lab study demonstrated dramatic effectiveness in killing leukemia cells, the findings were applied to studies on animal tissues and then on human cells in the laboratory.

The new findings are published on May 26, in the online issue of the Journal of Clinical Oncology.