May 27/London/Press Association Newsfile -- Green tea extract could prove to be a life-saver for leukemia patients, new research suggests.
Patients given high doses of the supplement saw significant improvements, including a 50% reduction in the size of swollen lymph glands. Researchers hope the active ingredient in green tea may increase the survival chances of leukemia patients with an aggressive form of the disease.
In an early-stage clinical trial, 33 patients with chronic lymphocytic leukemia (CLL) received eight different doses of a commercially produced green tea extract known as Polyphenon E. Lymphocyte count -- a measurement of numbers of white blood cells -- was lowered in one third of the participants, indicating cancer regression.
The supplement's primary active ingredient is a plant chemical called epigallocatechin gallate (EGCG), a powerful antioxidant. Tests have shown that EGCG can combat cancer in the laboratory, but there has been conflicting evidence from studies of its effects on patients.
Dr. Tait Shanafelt, from the Mayo Clinic in Rochester, Minn., who led the U.S. team conducting the latest trial, said, "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.
"The majority of individuals who entered the study with enlarged lymph nodes saw a 50% or greater decline in their lymph node size."
The findings were published in the Journal of Clinical Oncology.
CLL is the most common type of adult leukemia, affecting around 2,350 of the 7,200 patients diagnosed with the cancer each year in the United Kingdom. About half the patients with early stage diseases have an aggressive form of CLL that leads to early death.
The Mayo Clinic researchers hope EGCG may prevent rapid progression of the disease in these patients or improve the effectiveness of treatment when combined with other therapies. Patients taking part in the trial were given doses of Polyphenon E ranging from 400-2,000mg administered twice a day. The researchers found that even 2,000mg twice daily was not the maximum dose patients could tolerate.
A follow-up trial involving about the same number of patients is now under way. For this study, all patients will be given the maximum dose used in the first trial.
Ken Campbell, clinical information associate at the charity Leukemia Research, said, "These are interesting results, and it is unusual to see any patient benefit in these very early stage clinical trials.
"The authors do make it clear that further studies over a period of years will be needed to establish whether this will become a standard treatment for CLL.
"It should also be noted that it would not be possible to achieve these levels by drinking green tea; the study was carried out using a concentrated form of an active ingredient from green tea."
From the June 8, 2009, Prepared Foods E-dition