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Cancer Prev Res (Phila). 2017 Dec;10(12):710-718. doi: 10.1158/1940-6207.CAPR-17-0187. Epub 2017 Sep 13.

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

Author information

1
Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota.
2
Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania.
3
Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania.
4
Cancer Registry of Norway, Oslo, Norway.
5
Department of Nutrition, University of Oslo, Oslo, Norway.
6
Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, California.
7
Department of Radiology, University of Minnesota Medical School, Minneapolis, Minnesota.
8
Department of Family Medicine and Community Health, University of Minnesota Medical School, Minneapolis, Minnesota.
9
Department of Medicine, Division of Gastroenterology, Hepatology, & Nutrition, University of Minnesota, Minneapolis, Minnesota.
10
Virginia Piper Cancer Institute, Allina Health System, Minneapolis, Minnesota.
11
Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, Minnesota.
12
Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota.
13
Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, New Jersey.
14
Department of Medicine, University of Minnesota, Minneapolis, Minnesota.
15
Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota.
16
Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota. mkurzer@umn.edu.

Abstract

Epidemiologic 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 1,315 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 with the placebo with a 1.02% PMD increase from pre- to postintervention (P = 0.05), but had no effect in older women (Pinteraction = 0.07). GTE supplementation did not induce MD change in other subgroups of women stratified by catechol-O-methyltransferase genotype or level of body mass index. In conclusion, 1-year supplementation with a high dose of EGCG did not have a 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. Cancer Prev Res; 10(12); 710-8. ©2017 AACR.

PMID:
28904061
DOI:
10.1158/1940-6207.CAPR-17-0187
[Indexed for MEDLINE]
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