Green Tea Extract May Fight Leukemia
But the research is very preliminary, experts caution
FRIDAY, Dec. 23, 2005 (HealthDay News) -- A green tea extract called epigallocatechin gallate (EGCG) may benefit people with chronic lymphocytic leukemia (CLL), according to preliminary evidence in a Mayo Clinic case study of four patients.
The patients appeared to have an improvement in the clinical state of their disease after they starting taking over-the-counter products that contained EGCG, the study said. Three of the four patients met the standard criteria used to define treatment response in clinical trials. The findings were published online in Leukemia Research.
The same Mayo Clinic team previously found that, in test tubes, EGCG kills leukemia cells taken from patients with CLL by interrupting the communication signals the leukemia cells need to survive. That research was published in Blood in 2004.
"The experience of these individuals provides some suggestion that our previously published laboratory findings may actually translate into clinical effects for patients with the disease," study author and hematologist Dr. Tait Shanafelt said in a prepared statement.
However, he urged caution in interpreting the seemingly encouraging preliminary findings from this latest research.
"We do not know how many patients were taking similar products and failed to have any benefit. We also do not yet know the optimal dose that should be used, the frequency with which patients should take the medication, and what side effects will be observed with long-term administration," Shanafelt said.
More studies are needed to answer these questions. Shanafelt is lead investigator in an ongoing clinical trial examining doses of EGCG in pill form for CLL patients. The study is sponsored by the U.S. National Cancer Institute.
There is no known cure for CLL.
The U.S. National Cancer Institute has more about CLL.