Green tea may slow prostate tumor growth
Antioxidant compounds in green tea may help slow the growth and progression of prostate cancer, a preliminary study suggests.
Researchers found that among 26 men with prostate cancer, short-term treatment with the green tea compound epigallocatechin-3-gallate (EGCG) lowered the patients’ blood levels of several proteins linked to prostate cancer progression.
EGCG is the main polyphenol in green tea; polyphenols are antioxidant compounds that, research suggests, may help prevent the cell damage that promotes cancer development and progression.
The current study, which appears in the journal Cancer Prevention Research, does not prove that green tea compounds arrest prostate tumors’ spread.
But it does suggest that EGCG should be studied in larger clinical trials as a potential additional therapy for the disease, according to Dr. James R. Cardelli and colleagues at Louisiana State University Health Sciences Center in Shreveport.
A recent clinical trial in Italy found that men with a pre-cancerous condition called high-grade prostate intraepithelial neoplasia were less likely to develop prostate cancer over one year when they consumed green tea polyphenols.
“These studies are just the beginning and a lot of work remains to be done, however, we think that the use of tea polyphenols alone or in combination with other compounds currently used for cancer therapy should be explored as an approach to prevent cancer progression and recurrence,” Cardelli said in prepared statement from the American Association for Cancer Research.
The study included 26 men recently diagnosed with prostate cancer who were scheduled to have surgery to remove the tumor. Cardelli’s team had all of the patients consume four EGCG-containing capsules every day, up until the day before their surgery—typically for about one month.
The daily EGCG dose was equivalent to about a dozen cups of green tea.
Overall, the researchers found, the men’s levels of several blood proteins—including hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and prostate-specific antigen (PSA)—fell during the study period.
HGF and VEGF are both thought to play a role in cancer cells’ growth and spread. PSA, a protein produced by the prostate gland, tends to rise when prostate cancer develops or recurs.
The findings, according to the researchers, lay the groundwork for further randomized, placebo-controlled trials—the “gold standard” in medical research, where patients are randomly assigned to take the study drug or an inactive substance for comparison.
Pharmaceutical company Polyphenon Pharma supplied the EGCG capsules used in the study. None of the researchers involved in the study reports any financial interest in the product.
SOURCE: Cancer Prevention Research, July 2009.
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