A Randomized Controlled Trial of Green Tea Extract Supplementation and Mammographic Density in Postmenopausal Women at Increased Risk of Breast Cancer

Epidemiological and animal studies suggest a protective role of green tea against breast cancer. However the underlying mechanism is not understood. We conducted a randomized, double-blinded, placebo-controlled phase II clinical trial to investigate whether supplementation with green tea extract (GTE) modifies mammographic density (MD), as a potential mechanism, involving 1,075 healthy postmenopausal women. Women assigned to the treatment arm consumed daily 4 decaffeinated GTE capsules containing 1315 mg total catechins including 843 mg epigallocatechin-3-gallate (EGCG) for 12 months. A computer-assisted method (Madena) was used to assess MD in digital mammograms at baseline and month 12 time points in 932 completers (462 in GTE and 470 in placebo). GTE supplementation for 12 months did not significantly change percent MD (PMD) or absolute MD in all women. In younger women (50-55 years), GTE supplementation significantly reduced PMD by 4.40% as compared to the placebo with a 1.02% PMD increase from pre- to post-intervention (P = 0.05), but had no effect in older women (P-interaction = 0.07). GTE supplementation did not induce MD change in other subgroups of women stratified by catechol-O-methyltransferase (COMT) genotype or level of body mass index. In conclusion, one-year supplementation with a high dose of EGCG did not have significant effect on MD measures in all women, but reduced PMD in younger women, an age-dependent effect similar to those of tamoxifen. Further investigation of the potential chemopreventive effect of green tea intake on breast cancer risk in younger women is warranted.

from # All Medicine by Alexandros G. Sfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2jrhmc8
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